air quality monitoring techniques. principles and applications.

E UROPEAN UNION GOVERNMENT OF ROMANIA

SERBIAN GOVERNMENT

Structural Funds 2007 - 2013

UNIVERSITY „POLITEHNICA” f rom T IMISOARA

SUPORT DOCUMENTATION

BANATAIR SUSTAINABLE DEVELOPMENT FOR BANAT REGION BY MEANS OF ACADEMIC EDUCATION AND SCIENTIFIC RESEARCH & DEVELOPMENT IN TRANSBOUNDARY AIR QUALITY MONITORING ISSUES. http://banatair.mec.upt.ro

TECHNICAL GUIDANCE FOR STUDENTS AIR QUALITY MONITORING TECHNIQUES principles and applications

Prepared by Francisc Popescu

Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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CONTENT: 1. THE ENVIRONMENT ….....................................................................................................................................4 2. AIR QUALITY MONITORING...........................................................................................................................6 2.1. Criteria air pollutants.......................................................................................................................................6 2.1.1. Carbon monoxide (CO)................................................................................................................................6 2.1.2. Nitrogen oxides (NOx) .................................................................................................................................8 2.1.3. Sulphur oxides (SOx)....................................................................................................................................9 2.1.4. Particulate matter (PM).............................................................................................................................11 2.1.5. Non Methane Volatile Organic Compounds (NMVOC) ..........................................................................13 3. RELEVANT AIR QUALITY MONITORING TECHNIQUES.......................................................................15 3.1. Chemiluminescence (NOx)............................................................................................................................15 Horiba APNA 370 instrument. Principle and operation mode..........................................................................15 3.2. Fluorescence (SO2) .......................................................................................................................................18 Horiba APSA 370 instrument. Principle and operation mode. .........................................................................19 3.3. Non-dispersive Infrared Detection - NDIR (CO) ........................................................................................21 Horiba APMA 370 instrument. Principle and operation mode. ........................................................................22 3.4. Flame Ionization Detection - FID (CH4, NMHC and THC)......................................................................24 Horiba APHA 370 instrument. Principle and operation mode. ........................................................................25 3.5. Ultra-violet absorption (O3) .........................................................................................................................27 Horiba APOA 370 instrument. Principle and operation mode. ........................................................................28 3.6. Suspended particle measurement. PM1.0, PM2.5, PM4.0, PM10 and TSP ..............................................30 Sven Leckel LVS3. Principle and operation mode. ............................................................................................30 TSI DustTrack DRX 8533 instruments. Principle and operation mode. ...........................................................32 3.7. Differential Optical Absorption Spectroscopy (DOAS). .............................................................................34 SANOA .................................................................................................................................................................37 3.8. AIRPOINTER.................................................................................................................................................40 3.9. Meteorological data and AQM station setup...............................................................................................43 Literature:..............................................................................................................................................................44 NOTES ......................................................................................................................................................................45 Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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SUSTAINABLE DEVELOPMENT FOR BANAT REGION BY MEANS OF ACADEMIC EDUCATION AND SCIENTIFIC RESEARCH & DEVELOPMENT IN TRANSBOUNDARY AIR QUALITY MONITORING ISSUES. http://banatair.mec.upt.ro

Project Partners and team members

IOANA IONEL NICOLAE LONTI DORIN LELEA LUISA IZABEL DUNGAN GAVRIL TRIF-TORDAI GAVRIL BR TEANU VIRGIL STOICA FRANCISC POPESCU

MILAN PAVLOVIC ALEKSANDAR DJURIC MILAN NIKOLIC ALEKSANDAR PAVLOVIC ZELJKO KAMBEROVIC VESNA KELJACKI JANKOVIC SLOBODAN BRANKO DAVIDOVIC

GELU P DURE Team members of “Politehnica” University from Timisoara

Team members of Technical Faculty “Mihajlo Pupin” from Zrenjanin


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1. THE ENVIRONMENT … Environmental changes occur naturally and are a part of or the result of multiple cycles and interactions. Numerous natural cycles of the earth’s environment have been studied within the framework of three major scientific disciplines: chemistry, physics, and biology. Environmental scientists study the dynamics of cycles, such as the nitrogen and water cycles, and their relationships to soil geologic materials, surface waters, the atmosphere, and living organisms. The untrained observer may see the atmosphere as being separated from the earth’s surface. However, to the trained observer the environment is composed of integrated and interconnected cycles and domains. We now know that the environment is a continuum of physical, chemical, and biological processes that cannot be easily separated from one another. Water, for example, exists in three states and is found inside and on the surface of earth’s crust, in the atmosphere, and within living organisms. It is difficult to separate the physical, chemical, and biological processes of water within any particular environment, because water is transferred across boundaries. Humans now have a more holistic view of the environment and recognize that many factors determine its health and preservation. This in turn has led to the new term biocomplexity, which is defined as ‘‘the interdependence of elements within specific environmental systems, and the interactions between different types of systems.’’ Thus, research on the individual components of environmental systems provides limited information on the system itself. We are now also concerned with sustainable and renewable versus non-renewable natural resources as well as with biodiversity in relation to our own survival. Environmental monitoring is the observation and study of the environment. In scientific terms, we wish to collect data from which we can derive knowledge (Figure 1.1). Thus, environmental monitoring has its role defined in the first three steps of the staircase and is rooted in the scientific method. Objective observations produce sound data, which in turn produce valuable information. Information- derived knowledge usually leads to an enhanced understanding of the problem/situation, which improves the chances of making informed decisions. However, it is important to understand that other factors, including political, economic, and social factors, influence decision making. (Artiola et al. 2004) The information generated from monitoring activities can be used in a myriad of ways, ranging from understanding the short-term fate of an endangered fish species in a small stream, to defining the long-term management and preservation strategies of natural resources over vast tracts of land. Figure 1 lists some recognizable knowledge-based regulations and benefits of environmental monitoring. Although Figure 1 is not exhaustive, it does give an idea of the major role that environmental monitoring plays in our lives. Many of us are rarely aware that such regulations exist and that these are the result of ongoing monitoring activities. Nonetheless, we all receive the benefits associated with these activities. Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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Fig.1. The staircase of knowledge [1] Recently, environmental monitoring has become even more critical as human populations increase, adding ever-increasing strains on the environment. There are numerous examples of deleterious environmental changes that result from population increases and concentrated human activities. For example, in the United States or European Union states, the industrial and agricultural revolutions of the last 100 years have produced large amounts of waste by-products that, until the late 1960s, were released into the environment without regard to consequences. In many parts of the developing world, wastes are still disposed of without treatment. Through environmental monitoring we know that most surface soils, bodies of waters, and even ice caps contain trace and ultra trace levels of synthetic chemicals (e.g., dioxins) and nuclear-fallout components (e.g., radioactive cesium). Also, many surface waters, including rivers and lakes, contain trace concentrations of pesticides because of the results of agricultural runoff and rainfall tainted with atmospheric pollutants. The indirect effects of released chemicals into the environment are also a recent cause of concern. Carbon dioxide gas from automobiles and power plants and Freon (refrigerant gas) released into the atmosphere may be involved in deleterious climatic changes. (Artiola et al. 2004) Environmental monitoring is very broad and requires a multi-disciplinary scientific approach. Environmental scientists require skills in basic sciences such as chemistry, physics, biology, mathematics, statistics, and computer science. Therefore, all science-based disciplines are involved in this endeavor. This guide is composed of chapters that cover environmental monitoring from all aspects, including sampling methods, environmental characterization, and associated applications. The guide will cover both reference methods (so-called “standard methods”) and equivalent methods for air quality monitoring with a detailed explanations of principles and methodologies used. The focus of this textbook is on methods and strategies for environmental monitoring with emphasis on field methods. Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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2. AIR QUALITY MONITORING 2.1. Criteria air pollutants 2.1.1. Carbon monoxide (CO) Carbon monoxide is an odorless, colorless and toxic gas. Because it is impossible to see, taste or smell the toxic fumes, CO can kill you before you are aware it is in your home. At lower levels of exposure, CO causes mild effects that are often mistaken for the flu. These symptoms include headaches, dizziness, disorientation, nausea and fatigue. The effects of CO exposure can vary greatly from person to person depending on age, overall health and the concentration and length of exposure. Carbon monoxide is mainly produced as an intermediary product of combustion processes in piston engines and boilers. The oxidation of CO into CO2 requires a temperature of minimum 990 K and a sufficient stationary time into the combustion chamber. If the combustion temperature is not high enough or uniform inside the combustion chamber, when the exhaust gases are evacuated some CO will not oxidize. Ambient CO concentrations in metropolitan areas are orders of magnitude higher than background. These levels are primarily associated with transportation emissions and are closely related to traffic density and meteorological conditions. Highest concentrations occur along major traffic arteries during morning and evening rush hours and decrease relatively rapidly with distance from roadways. Peak levels averaged over 1 h vary from about 5 to more than 10 ppmv in some cities. Elevated CO levels tend to plague cities that have high traffic densities and are located at relatively high altitudes. (Godish, 2004) CO concentrations are significantly and more important than regulatory concerns would indicate. Carbon monoxide affects tropospheric concentrations of both hydroxyl radical (OH-) and O3 and, as a consequence, the oxidizing potential of the atmosphere. Because CO and CH4 (a major greenhouse gas) compete for OH-, CO indirectly affects tropospheric concentrations of CH4 and stratospheric H2O vapor (derived from CH4 oxidation). In figure 2 the contribution of key categories to EU-27 emissions of carbon monoxide are presented for year 2006 (EEA, 2008) and in figure 3 the sources of CO emissions, by sector, for USA in 2005 (US-EPA, 2005). A very important issue is that in the EU-27, emissions of CO decreased by just over 53 % between 1990 and 2006. Decreased emissions were reported in all Member States except Romania. The largest absolute decreases were reported by France, Germany, Italy, Poland, Spain and the United Kingdom; however, these countries remained the largest emitters of CO in absolute terms in 2006. (EEA, 2008)


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Fig. 2. EU-27 emission sources of carbon monoxide, 2006.

Fig. 3. USA emission sources of carbon monoxide, 2005. The effects of carbon monoxide on human health are caused due to the fact that CO enters the bloodstream through the lungs and attaches to hemoglobin (Hb), the body's oxygen carrier, forming carboxyhemoglobin (COHb) and thereby reducing oxygen (O2) delivery to the body's organs and tissues. High COHb concentrations are poisonous. Central nervous system (CNS) effects in individuals suffering acute CO poisoning cover a wide range, depending on severity of exposure: headache, dizziness, weakness, nausea, vomiting, disorientation, confusion, collapse, and coma. At lower concentrations, CNS effects include reduction in visual perception, manual dexterity, learning, driving performance, and attention level. Earlier work is frequently cited to justify the statement that CO exposure sufficient to produce COHb levels of ca. 5% would be sufficient to produce visual sensitivity reduction and various neurobehavioral performance Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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deficits. In a recent literature re-evaluation, however, the best estimate was that (COHb) would have to rise to 15-20% before a 10% reduction in any behavioral or visual measurement could be observed. (Raub, 2002) Carbon monoxide (CO) may be the cause of more than one-half of the fatal poisonings reported in many countries: fatal cases also are grossly under-reported or misdiagnosed by medical professionals. Therefore, the precise number of individuals who have suffered from CO intoxication is not known. In conclusion, CO poisoning occurs frequently; has severe consequences, including immediate death involves complications and often is overlooked. Efforts in prevention and in public and medical education should be encouraged. (Raub, 2002) 2.1.2. Nitrogen oxides (NOx) Nitrous oxide concentrations in the atmosphere have been increasing steadily since preindustrial times, from ~280 to ~320 ppbv today. Estimated annual emissions to the atmosphere are 13.8 Tg (tetragrams) N/year, with ~70% being produced by nitrification and denitrification processes in undisturbed terrestrial environments and the world’s oceans. About 3 Tg N/year, or ~8%, is associated with agricultural tillage, fertilizer use, and animal wastes. In case of combustion equipments the NOx are formed during the combustion process at high temperatures by the oxidation of nitrogen content of fuel and combustion air. In a first phase only NO is formed while the NO2 is mainly formed after the combustion in exhaust process when more O2 is present and into the atmosphere. The main anthropogenic sources of nitrogen oxides are road transport and public electricity and heat sector. In figure 4 the contribution of key categories to EU-27 emissions of nitrogen oxides are presented for year 2006 (EEA, 2008) and in figure 5 the sources of NOx emissions, by sector, for USA in 2005 (US-EPA, 2005).

Fig. 4. EU-27 emission sources of nitrogen oxides, 2006.


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Fig. 5. USA emission sources of nitrogen oxides, 2005.

2.1.3. Sulphur oxides (SOx) All fossil fuels contain sulphur, most of which is released as sulphur dioxide during combustion. Almost all the anthropogenic sulphur contribution is due to fossil fuel combustion. Different fuels offer a wide range of sulphur contents (Colls, 2002): Oil and its by-products contain between 0.1% sulphur (paraffin) and 3% (heavy fuel oil) in the form of sulphides and thiols. Petrol contains negligible sulphur in the context of overall mass emissions, although there can be an odor problem from conversion to hydrogen sulphide (H2S) on catalytic converters. Coal contains 0.1–4% sulphur, mainly as flakes of iron pyrites (FeS2). The average sulphur content of European coal reservoirs is 1.7%. Natural gas (mainly methane, CH4) can be up to 40% H2S when it is extracted from the well. The sulphur is taken out very efficiently at a chemical processing plant before distribution, so natural gas is effectively sulphur free. Global sulphur dioxide emissions are estimated to have increased from 4 Mt (containing 2 Mt of sulphur) in 1860 to 150 Mt in 1990. The emissions from the US and Europe increased steadily until the 1970s before coming under control. Sulphur emissions from the faster-growing Asian region have continued to increase, due largely to coal combustion. Emissions from China are now comparable to those from the US, and in 1990 emissions from China, US and Russia accounted for over half the global total. The EU-27 total SOX emissions in 2006 were 7 946 Gg. This is almost a 70 % reduction compared to the level of emissions reported in 1990. Since 1990, SO X emissions have increased in only two Member States: Romania (21.9 %) and Greece (11.9 %). Inspection of the time-series trends for Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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some Member States shows some step changes in emission reductions have occurred since 1990. For example, emissions of SO2 in Slovenia fell considerably in 2001 and again in 2005 due to the introduction of flue gas desulphurization abatement equipment in thermal power plants. In figure 6 the contribution of key categories to EU-27 emissions of sulphur oxides are presented for year 2006 (EEA, 2008) and in figure 7 the sources of SOx emissions, by sector, for USA in 2005 (US-EPA, 2005). The natural sources are now heavily outweighed by human ones, principally fossil fuel combustion. Since 90% of the biogenic emission is as dimethyl sulphide, and an even higher proportion of the human emission is as SO2, we have a clear demarcation between the source types. Since most of the dimethyl sulphide comes from oceans in the southern hemisphere, and most of the human SO2 from fossil fuel emissions in the northern hemisphere, we also have a geographical split.

Fig. 6. EU-27 emission sources of sulphur oxides, 2006.

Fig. 7. USA emission sources of sulphur oxides, 2005. Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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2.1.4. Particulate matter (PM) Particulate matter is a collective term used to describe small solid and liquid particles that are present in the atmosphere over relatively brief (minutes) to extended periods of time (days to weeks). Individual particles vary in size, geometry, mass, concentration, chemical composition, and physical properties. They may be produced naturally or as a direct or indirect result of human activities. Of major concern are particles < 10 m because they can remain suspended in the atmosphere where (depending on actual particle size) they can settle out relatively slowly. Atmospheric aerosol is characterized by these relatively small particles. The formation and increase of atmospheric aerosol by both natural and anthropogenic sources is a major air quality concern because aerosol particles may scatter light, reducing visibility, pose an inhalation hazard to humans and animals, affect climate on a regional and global scale. Particulate matter can be described as being primary or secondary, based on its origin and processes of formation. Primary particles are emitted directly into the atmosphere from a variety of natural and anthropogenic sources. The natural particle sources include volcanoes, forest fires, ocean spray, biologic sources and the anthropogenic sources of particles are transportation, fuel combustion in stationary sources, a variety of industrial processes, solid waste disposal and miscellaneous sources such as agricultural activities and fugitive emissions from roadways. Secondary particles are formed in the atmosphere as a result of chemical processes involving gases, aerosol particles, and moisture. In figure 8 the contribution of key categories to EU-27 emissions of particle matter, PM10 fraction, are presented for year 2006 (EEA, 2008) and in figure 9 the sources of particle matter, PM10 fraction, by sector, for USA in 2005 (US-EPA, 2005).

Fig. 8. EU-27 emission sources of PM10, 2006.


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Fig. 9. USA emission sources of PM10, 2005. In figure 10 the sources and diameter of representative particle matter fractions, thoracic (PM10, Respirable (PM4.0) and total suspended particles (TSP) are synthesized.

Fig. 10. Type of particles and their sources. (TSI, 2010)


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2.1.5. Non Methane Volatile Organic Compounds (NMVOC) The anthropogenic fraction of atmospheric VOCs is related to the unprecedented usage of fossil fuels for transport, the production of consumer goods and various industrial processes in the past centuries. The distinction between biogenic and anthropogenic VOCs in the atmosphere is far from straightforward because many VOC species are produced by both sources. Emissions of alkanes and alkenes, for example, are dominated by anthropogenic sources, but are also produced by soils, wetlands and oceans. (Koppmann, 2007) The larges sources of NMVOC emissions are use of fossil fuel in transportation and chemistry industry. Mobile sources can be divided into emissions from the exhaust and fugitive emissions by evaporation. Stationary emissions from the use of fossil fuel are due to industrial applications (e.g. refineries and chemical sector). Emissions related to production, storage and delivery of fossil fuels predominately occur in those regions where extensive fossil fuel drilling activities exist. However, fugitive emissions can also occur from the transport and distribution of the fuel, such as ships, road tankers and fuel stations. After their release into the atmosphere, VOCs are oxygenated by photochemical processes, which finally lead to their removal from the atmosphere. For most VOCs the process is initiated by atmospheric radicals like OH, O3, NO3 and Cl, with the OH radical being by far the most important reactant. The atmospheric lifetime of an individual VOC species is dependent on its chemical structure, the radical concentration and the intensity of solar radiation. When VOCs are degraded in polluted air masses, NO is oxygenated to NO2, which then gets photolysed and contributes to the formation of tropospheric ozone, a key issue in air pollution control. In the EU-27, NMVOC emissions declined by just under 45 % between 1990 and 2006. Twenty-three countries reported reductions (Belgium, Germany, Luxembourg the Netherlands and the United Kingdom have reduced emissions by more than 60 % during this period). The four countries that reported increased NMVOC emissions are Bulgaria, Greece, Poland and Romania.

Fig. 11. EU-27 emission sources of NMVOC, 2006.


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Fig. 12. USA emission sources of NMVOC, 2005. The ability of NMVOCs to cause health effects varies greatly from those that are highly toxic, to those with no known health effect. As with other pollutants, the extent and nature of the health effect will depend on many factors including level of exposure and length of time exposed. Eye and respiratory tract irritation, headaches, dizziness, visual disorders, and memory impairment are among the immediate symptoms that some people have experienced soon after exposure to some organics. At present, not much is known about what health effects occur from the levels of organics usually found in homes. Many organic compounds are known to cause cancer in animals; some are suspected of causing, or are known to cause, cancer in humans.


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3. RELEVANT AIR QUALITY MONITORING TECHNIQUES 3.1. Chemiluminescence (NOx) The chemiluminescence method offers the best results both in sensitivity and stability for measuring low NO concentrations in ambient air. The reaction scheme is as follows: NO NO

O3

NO2 * 2

O3

NO2*

NO NO2

* 2

NO

NO

O2 O2

hv M

The radiation emission is in the wavelength between 600 and 3000 nm with a maximum of intensity at approximately 1200 nm. This chemilumeniscence signal is detected photo electrically. When O3 is present in excess the resulted signal is proportionally with NO concentration in the sample gas. The largest NO2* returns to ground state without radiation emission, due to a collision with other molecules M. In order to enhance the light yield the pressure in the reaction chamber is reduced. Quenching is an unwanted phenomenon and the extend to witch it occurs depends on the character of the colliding molecule M. For instance water H2 O and carbon dioxide CO2 quench NO chemiluminescence more effectively than nitrogen N2 and oxygen O2. In order to measure NO2 in the sample gas it is first converted into NO into a chemical converter heated at 300 °C and the results NO is measured as NO2. If the converter, for examples, contains carbon C as reducing agent the following reaction takes place: NO2

C

NO

CO

Horiba APNA 370 instrument. Principle and operation mode. In this training session we will use an HORIBA APNA 370 Instrument. The APNA-370 continuously monitors atmospheric NOX, NO2, and NO concentrations using a cross-flow modulated semi decompression chemiluminescence method. The APNA-370 employs an independent, internal dry-method sampling device to achieve the highest levels of sensitivity and accuracy. The dry method, due to its minimal maintenance requirements and capability of continuous monitoring and instantaneous analysis of gas in its unaltered state, has been a preferred method for monitoring the atmospheric pollution. The APNA-370 uses a combination of the dual cross flow modulation type chemiluminescence principle and the referential calculation method. This gives it the advantages of the single-detector method plus the ability to do continuous measurements of NOX, NO, and NO2. The design gives great stability and extremely high


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sensitivity (0.1 ppm F.S.) Standard equipment includes a drier unit with an automatic recycle function to provide dry ambient air as the ozone source. This makes long-term continuous measurements possible. The detector uses a silicon photodiode sensor to reduce size and prolong working life. All the necessary features are built right into a single rack-sized unit, including a reference-gas generator, an ozone-source drier unit, an ozone decomposer, and a sampling pump. No supplemental gas is required. The instrument has standard ranges: 0-0.1/0.2/0.5/1.0 ppm, auto range or manual range selectable, a repeatability of ±1.0% of F.S., a linearity of ±1.0% of F.S. and a sample gas flow rate of approx. 0.8L/min

Fig. 13. Horiba APNA370 principle of operation and flow diagram

Fig. 14. HORIBA APNA370 control screens


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The instrument operates under the reference method described in EN 14211:2005. Among the multiple possibilities to setup and operate the instrument, the most relevant are the two control screens presented in figure 14. The first screen is the visualization screen. On the top the sign “O3” shows that the O3 generator in working, the label “MEAS.” shows that the instrument is in measuring mode and the middle section presents the instantaneous values for NO, NO2 and NOx. The second screen in the calibration control screen. Depending on what input the gas is introduces the mode label can be “MEAS.”, “ZERO” or “SPAN”. In case of automatic calibrations the bottles with zero air and span gas are permanently connected to the instrument and the calibration is performed automatically. In our case we will use the manual calibration method and the zero air and sample gas will be introduced thru the sample inlet. The following steps are to be taken for the calibration procedure: - start the instrument and allow to reach correct working parameters (about 30 minutes) - on the main screen (touch panel) command “Cal.” - the calibration screen will open. - manually input the span gas concentration, in our case 315 ppb NO - connect the N2 bottle to the sample input (back panel of the instrument) and make sure that the N2 gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute - the instrument reading will fall to zero, allow the instrument reading to stabilize for 5 minutes. If the NO, NO2 and NOx readings are not zero touch the panel on the “ZERO SET”. - The zero calibration in done. - disconnect the N2 bottle and connect the NO bottle to the sample input (back panel of the instrument). Make sure that the NO concentration on the bottle label is identical with one on the instrument. In our case is 315 ppb NO. - again, make sure that the NO gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute. - the instrument reading will raise to 315 ppb NO, allow the instrument reading to stabilize for 5 minutes. If the NO and NOx readings are not 315 ppb touch the panel on the “SPAN SET”. - the span calibration in done. - disconnect the NO bottle and reconnect the sample inlet. - the instrument will start to measure the ambient air (thru sample inlet) NO, NO2 and NOx concentrations - connect the instrument analog output to the PC data acquisition board and verify that the instrument readings and the PC DAQ are identical. The instrument is calibrated and ready for measurement.


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3.2. Fluorescence (SO2) The research on atmospheric air indicates that sulfur dioxide has a stronger absorption in emission lines of 218.9 nm and 220.8 nm. The sulfur dioxide (SO*) of excited state was yielded after SO2 absorbing UV light energy. When SO* retune to base state, one of mode transformed energy is releasing fluorescence. When low concentration of S02 and short absorption optical path, the fluorescence intensity, F, is given by: F

G K L I0 L ( SO2 ) K f Kq Kd

Where G is geometry constant of reaction chamber, I0 is intensity of excitation light, is the absorption coefficient of SO2, L is the optical path length, (SO2) is concentration of SO2, Kf is fluorescence constant, Kq is quenching constant of fluorescence and Kd is dissociation constant. The G, Kf, Kq, Kd, I0, , L may be consider a constant because they are depending on the system configuration and build-up solution. Sulfur dioxide in atmospheric air has three absorption regions (340-390 m, 250-320 m, and 19O23O m).The strongest absorption region is in 190-230 nm. The strongest SO2 fluorescence will be yielded if used 218.9 nm or 220.8 nm as excitation light. There are three common light sources used including line spectrum near by 218.9 nm, 220.8 nm, for instance Zn lamp include 213.8 nm, Sb lamp (217.5nm), Cd lamp (228.8) and xenon lamp has line and continuous spectrum. We should consider interfere of coexistence gases in air and influence of humidity on fluorescence quenching. The research found that influence of fluorescence quenching is differ in difference light supply and found not influence of humidity on fluorescence quenching of S0 2, and the fluorescence intensity of background gases is very weak, when used 213.8 nm line of Zn lamp as exciting light.

Fig.15: SO2 fluorescence instrument. Principle schematic. (Zolner, 1984) Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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When excitation light is irradiated and absorbed following processes take place: Process 1: S02 + hv1 -> S02* There are three ways by which the S02* loses its excitation energy. * Process 2: Fluorescence process: Excitation energy is emitted as fluorescence. SO2

kf

SO2

Kv 2

kd * SO O Process 3: Dissociation process: Excitation energy is used for dissociation. SO 2 Process 4: Quenching process: Excitation energy is lost by collision with surrounding molecules, M.

SO 2 *

M

kq

SO 2

M

Practically, the excitation energy is lost resulting from the confluence of these three processes.

Horiba APSA 370 instrument. Principle and operation mode. The instrument has standard ranges: 0-0.1/0.2/0.5/10.0 ppm, auto range or manual range selectable, a repeatability of ±1.0% of F.S., a linearity of ±1.0% of F.S. and a sample gas flow rate of approx. 0.7L/min

Fig. 16. Horiba APSA370 principle of operation and flow diagram

Fig. 17. HORIBA APSA370 control screens Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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The instrument operates under the reference method described in EN 14212:2005. Among the multiple possibilities to setup and operate the instrument, the most relevant are the two control screens presented in figure 17. The first screen is the visualization screen. The label “MEAS.” shows that the instrument is in measuring mode and the middle section presents the instantaneous values for SO 2 concentration. The second screen in the calibration control screen. Depending on what input the gas is introduces the mode label can be “MEAS.”, “ZERO” or “SPAN”. In case of automatic calibrations the bottles with zero air and span gas are permanently connected to the instrument and the calibration is performed automatically. In our case we will use the manual calibration method and the zero air and sample gas will be introduced thru the sample inlet. The following steps are to be taken for the calibration procedure: - start the instrument and allow to reach correct working parameters (about 30 minutes) - on the main screen (touch panel) command “Cal.” - the calibration screen will open. - manually input the span gas concentration, in our case 247 ppb SO2 - connect the N2 bottle to the sample input (back panel of the instrument) and make sure that the N2 gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute - the instrument reading will fall to zero, allow the instrument reading to stabilize for 5 minutes. If the SO2 readings are not zero touch the panel on the “ZERO SET”. - The zero calibration in done. - disconnect the N2 bottle and connect the SO2 bottle to the sample input (back panel of the instrument). Make sure that the SO2 concentration on the bottle label is identical with one on the instrument. In our case is 247 ppb SO2. - again, make sure that the SO2 gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute. - the instrument reading will raise to 247 ppb SO2, allow the instrument reading to stabilize for 5 minutes. If the SO2 readings are not 247 ppb touch the panel on the “SPAN SET”. - the span calibration in done. - disconnect the SO2 bottle and reconnect the sample inlet. - the instrument will start to measure the ambient air (thru sample inlet) SO2 concentrations - connect the instrument analog output to the PC data acquisition board and verify that the instrument readings and the PC DAQ are identical. The instrument is calibrated and ready for measurement.


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3.3. Non-dispersive Infrared Detection - NDIR (CO) NDIR instruments are primarily used for emission measurements; analyzers are mainly suitable for the determination of the gases CO, CO2, NO, SO2, H2O, CH4, C2H6 , and many other hydrocarbons. For CO and CO2, NDIR photometry is the most commonly used measuring technique, which is also unrivalled in its application for the measurement of these gases in the ambient air range. The instruments for CO measurements uses the modulation effect that occurs with infrared absorption of sample gas itself when sample gas and zero gas are alternately sent to its cell at a certain flow rate using a solenoid valve which is actuated at a frequency of 1 Hz. Unless the gas concentration of the measured component is changed in the cell, the output from the detector essentially becomes zero, therefore, the zero drift dose not occur. Since the instrument also uses the AS-type detector, extremely high-accuracy results are obtained without any effect of the interference component. The radiation source is an infrared radiation emitter. The radiation - modulated by a chopper - passes a chamber containing the probe and in parallels a chamber containing a reference gas. To reduce the influence of interfering gases optical filters are used. The content of the measurement cell receives periodically infrared radiation with different strength, which results in different temperature and pressure effects. The pressure effects are hence transferred to electrical signals by a sensor, and this signal correlates to the measured CO concentration. Some systems use the pressure waves for detection, while others use directly the IR receiving an optical detector to measure the CO concentration.

Fig. 18. CO/CO2 NDIR instrument. Principle schematic. (http://www.cambustion.com)


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Horiba APMA 370 instrument. Principle and operation mode. The instrument has standard ranges: 0-5/10/20/50 ppm, auto range or manual range selectable, a repeatability of ±1.0% of F.S., a linearity of ±1.0% of F.S. and a sample gas flow rate of approx. 1.5L/min

Fig. 19. Horiba APMA370 principle of operation and flow diagram

Fig. 20. HORIBA APMA370 control screens


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The instrument operates under the reference method described in EN 14626:2005 and is a cross flow modulation type, infrared-absorption technology that eliminates the need for adjusting optical alignment. Conventional technology uses an optical chopper to obtain modulation signal but APMA370 uses solenoid valve cross flow modulation. Among the multiple possibilities to setup and operate the instrument, the most relevant are the two control screens presented in figure 20. The first screen is the visualization screen. The label “MEAS.” shows that the instrument is in measuring mode and the middle section presents the instantaneous values for CO concentration. The second screen in the calibration control screen. Depending on what input the gas is introduces the mode label can be “MEAS.”, “ZERO” or “SPAN”. In case of automatic calibrations the bottles with zero air and span gas are permanently connected to the instrument and the calibration is performed automatically. In our case we will use the manual calibration method and the zero air and sample gas will be introduced thru the sample inlet. The following steps are to be taken for the calibration procedure: - start the instrument and allow to reach correct working parameters (about 30 minutes) - on the main screen (touch panel) command “Cal.” - the calibration screen will open. - manually input the span gas concentration, in our case 9.98 ppm CO - connect the N2 bottle to the sample input (back panel of the instrument) and make sure that the N2 gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute - the instrument reading will fall to zero, allow the instrument reading to stabilize for 5 minutes. If the CO readings are not zero touch the panel on the “ZERO SET”. - The zero calibration in done. - disconnect the N2 bottle and connect the CO bottle to the sample input (back panel of the instrument). Make sure that the CO concentration on the bottle label is identical with one on the instrument. In our case is 9.98 ppm CO. - again, make sure that the CO gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute. - the instrument reading will raise to 9.98 ppm CO, allow the instrument reading to stabilize for 5 minutes. If the CO readings are not 9.98 ppm touch the panel on the “SPAN SET”. - the span calibration in done. - disconnect the CO bottle and reconnect the sample inlet. - the instrument will start to measure the ambient air (thru sample inlet) CO concentrations - connect the instrument analog output to the PC data acquisition board and verify that the instrument readings and the PC DAQ are identical. The instrument is calibrated and ready for measurement.


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3.4. Flame Ionization Detection - FID (CH4, NMHC and THC) The so-called flame-ionization detector (FID) was originally developed for gas chromatography. Nowadays, it is also used as the most important measuring device for the continuous recording of organic substances in exhaust gases or in ambient air. The measuring principle of the FID is classic and will be summarized here with the help of Fig 21.

Fig. 21. Diagram of a flame ionization detector (FID) (Kaiser, 1965). The hydrogen flame burns out of a metal nozzle which simultaneously represents the negative electrode of an ionization chamber. The positive counter-electrode is fixed above the flame, e.g., as a ring. Between the two electrodes direct voltage is applied. The ion current is measured as a voltage drop above the resistor W. The measuring gas is added to the burning gas shortly before entering the burner nozzle. The air required for combustion flows in through a ring slot around the burner nozzle. For stable measuring conditions it is essential that all gases - combustion gas, combustion air and measuring gas - are conducted into the flame in constant volume flows. For this, all gas flows are conducted via capillaries. Constant pressures before the capillaries ensure a constant flow. Sensitive pressure regulators for combustion gas and combustion air are used to achieve this fine-tuning. The measuring gas is pumped past the capillary in the bypass in a great volume flow. Pressure is kept constant by the back pressure regulator, so that a constant partial flow reaches the flame via the capillary. Most FID’s operate with overpressure, i.e., the measuring gas pump is located before the capillary. To avoid condensation of the hydrocarbons to be measured almost all instruments can be heated to 150-200 °C. Heating includes the particle filter and the measuring gas pump; in most cases, particularly with warm exhaust gases, a heated sampling line is also used from measuring gas sampling to the measuring instrument. Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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Horiba APHA 370 instrument. Principle and operation mode. In this training session we will use an HORIBA APHA 370 Instrument. The APHA-370 continuously monitors atmospheric CH4, NMHC (VOC) and THC concentrations using a combination of the flame ionization detection method and selective combustion. This gives it the great advantage of yhe single-detector method plus the ability to perform continuous measurements free of zero drift for THC, NMHC and CH4. The instrument has standard ranges: 0-0.1/0.2/0.5/1.0 ppm, auto range or manual range selectable, a repeatability of ±1.0% of F.S., a linearity of ±1.0% of F.S. and a sample gas flow rate of approx. 0.8L/min

Fig. 22. Horiba APHA370 principle of operation and flow diagram

Fig. 23. HORIBA APHA370 control screens


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The instrument operates under the reference method described in EN 12619:2002 and EN 13526:2002. Among the multiple possibilities to setup and operate the instrument, the most relevant are the two control screens presented in figure 23. The first screen is the visualization screen. On the top the sign “flame” shows that the flame occurred and that the instrument FID detection has started, the label “MEAS.” shows that the instrument is in measuring mode and the middle section presents the instantaneous values for CH4, NMHC and THC. The second screen in the calibration control screen. Depending on what input the gas is introduces the mode label can be “MEAS.”, “ZERO” or “SPAN”. In case of automatic calibrations the bottles with zero air and span gas are permanently connected to the instrument and the calibration is performed automatically. In our case we will use the manual calibration method and the zero air and sample gas will be introduced thru the sample inlet. The following steps are to be taken for the calibration procedure: - start the instrument and allow to reach correct working parameters (about 30 minutes) - on the main screen (touch panel) command “Cal.” - the calibration screen will open. - manually input the span gas concentration, in our case 14.9 ppm CH4. - connect the N2 bottle to the sample input (back panel of the instrument) and make sure that the N2 gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute - the instrument reading will fall to zero, allow the instrument reading to stabilize for 5 minutes. If the CH4, NMHC and THC readings are not zero touch the panel on the “ZERO SET”. - The zero calibration in done. - disconnect the N2 bottle and connect the CH4 bottle to the sample input (back panel of the instrument). Make sure that the CH4 concentration on the bottle label is identical with one on the instrument. In our case is 14.9 ppm CH4. - again, make sure that the CH4 gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute. - the instrument reading will raise to 14.9 ppm CH4, allow the instrument reading to stabilize for 5 minutes. If the CH4 and THC readings are not 14.9 ppm touch the panel on the “SPAN SET”. - the span calibration in done. - disconnect the CH4 bottle and reconnect the sample inlet. - the instrument will start to measure the ambient air (thru sample inlet) CH4, NMHC and THC concentrations - connect the instrument analog output to the PC data acquisition board and verify that the instrument readings and the PC DAQ are identical. The instrument is calibrated and ready for measurement.


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3.5. Ultra-violet absorption (O3) The detection of ozone molecules is based on the absorption of 254 nm UV light due to an internal electronic resonance of the O3 molecule. A typical O3 monitor uses a mercury lamp constructed so that a large majority of the light emitted is at the 254 nm wavelength. Light from the UV lamp shines through an absorption cell through which the sample gas being measured is passed. The ratio of the intensity of light passing through the gas is calculated from the UV light intensity measured by a sensor and a reference measurement provided by the reference sensor, which does not pass through the gas, forms the ratio I/I0. This ratio forms the basis for the calculation of the ozone concentration. The Beer-Lambert equation, shown below, calculates the concentration of ozone from the ratio of light intensities.

CO 3

1 a L

T 1013 mbar 273. 15 p

ln

S1 S2

Where: S1 Intensity of light passed through the sample S2 Intensity of light through ozone free gas sample a Absorption coefficient L Path length C03 Concentration of ozone T Sample temperature in degrees Kelvin p Pressure in mbar (absolute) As can be seen the concentration of ozone depends on more than the intensity ratio. Temperature and pressure influence the density of the sample. The density changes the number of ozone molecules in the absorption cell, which impacts the amount of light, removed from the light beam. These effects are addressed by directly measuring temperature and pressure and including their actual values in the calculation. The absorption coefficient is a number that reflects the inherent ability of ozone gas to absorb 254 nm wavelength of the UV light. Lastly, the absorption path length determines how many molecules are present in the column of gas in the absorption cell. The intensity of light is converted into a voltage by the detector/preamplifier. The voltage is converted into a number by a voltage-to-frequency (V/F) converter at high resolution. The digitized signal, along with the other variables, is used by the CPU to compute the concentration of ozone using the above formula.


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Horiba APOA 370 instrument. Principle and operation mode. The Horiba APOA370 instrument uses the cross flow modulation type, ultra-violet absorption method in conjunction with the comparative calculation method that permits continuous measurement with great stability and high sensitivity. The instrument heated deozonizer provides reference gas by decomposing the O3 found in the sample gas. The instrument has standard ranges: 0-0.1/0.2/0.5/1.0 ppm, auto range or manual range selectable, a repeatability of ±1.0% of F.S., a linearity of ±1.0% of F.S. and a sample gas flow rate of approx. 0.7L/min

Fig. 24. Horiba APOA370 principle of operation and flow diagram

Fig. 25. HORIBA APOA370 calibration control screen Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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The instrument operates under the reference method described in EN 14625:2005 and is a cross flow modulation type, ultraviolet technology. Among the multiple possibilities to setup and operate the instrument, the most relevant are the two control screens presented in figure 25. Depending on what input the gas is introduces the mode label can be “MEAS.”, “ZERO” or “SPAN”. In case of automatic calibrations the bottles with zero air and span gas are permanently connected to the instrument and the calibration is performed automatically. In our case we will use the manual calibration method and the zero air and sample gas will be introduced thru the sample inlet. The following steps are to be taken for the calibration procedure: - start the instrument and allow to reach correct working parameters (about 30 minutes) - on the main screen (touch panel) command “Cal.” - the calibration screen will open. - manually input the span gas concentration, in our case 264 ppb O3, from internal O3 generator. - connect the N2 bottle to the sample input (back panel of the instrument) and make sure that the N2 gas is provided in excess by controlling the bottle valve and reading the excess flow meter, it should be around 2 l/minute - the instrument reading will fall to zero, allow the instrument reading to stabilize for 5 minutes. If the O3 readings are not zero touch the panel on the “ZERO SET”. - The zero calibration in done. - disconnect the N2 bottle and choose (from the touch screen) the mode “SPAN”. The internal O3 generator will start to generate reference O3 in concentration of 264 ppb. - the instrument reading will raise to 264 ppb O3, allow the instrument reading to stabilize for 5 minutes. If the O3 readings are not 264 ppb touch the panel on the “SPAN SET”. - the span calibration in done. - Choose the mode “MEAS.”. - the instrument will start to measure the ambient air (thru sample inlet) O3 concentrations - connect the instrument analog output to the PC data acquisition board and verify that the instrument readings and the PC DAQ are identical. The instrument is calibrated and ready for measurement.


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3.6. Suspended particle measurement. PM1.0, PM2.5, PM4.0, PM10 and TSP Suspended particulate matter (SPM) in air generally is considered to be all airborne solid and low vapor pressure liquid particles. Suspended particulate matter in ambient air is a complex, multi-phase system consisting of a spectrum of aerodynamic particle sizes ranging from below 0.01 m to 100 m and larger. (US-EPA) Respirable particles are attributed to growth of particles from the gas phase and subsequent agglomeration; most coarse particle (sizes 2.5-10 m) are made of mechanically abraded or ground particles. Particles that have grown from the gas phase, either because of condensation, transformation, or combustion, occur initially as very fine nuclei (0.05 m). These particles tend to grow rapidly to accumulation mode particles around 0.5 m which are relatively stable in the air. Coarse particles, on the other hand, are mainly produced by mechanical forces, such as crushing and abrasion. These coarse particles therefore normally consist of finely divided minerals, soil, or dust that result from entrainment by the motion of air or from other mechanical action within their area. Since the mass of these particles is normally >3 m, their retention time in the air parcel is shorter than that of the fine particle fraction. These smaller particles penetrate deeply into the lung, where the potential for health effects is the greatest. In addition, the smaller particles typically are man-made. TSP typically has a bimodal distribution, with naturally occurring particles centered at about 10 m and man-made particles centered at about 0.4 m (US-EPA). Sampling options for PM10 compliance monitoring fall into two categories: "reference" methods and "equivalent" methods. In this moment the gravimetric method is the reference method and there are 3 “equivalent” methods accepted by regulations: Beta-radiation attenuation, oscillating pendulum and light scattering. Reference standard: EN12341 Sven Leckel LVS3. Principle and operation mode. The reference method monitors are so called “LSV”, Low Volume Samplers and are used for PM10, TSP and PM2.5 measurements indoor and outdoor. The particles retained on the quartz or glass filters can be analyzed gravimetric but also chemical, in the laboratory, to analyze the content of the deposited particles. The working principle of the LVS is: the sample air is aspirated with a vacuum pump (maximum flow is 3 m 3/h). The glass or teflon/quarz filter is stored inside the inlet. The inlet is build so that only particle below the given aerodynamic diameter (2.5 m or 10 m) will be deposited on the filter. The air will be exhausted through a paper filter in order to retain the particles that could be generated by the vacuum pump. The filter is weighted before and after the sampling with a balance with 0.00000 g precision. The difference represents the concentration of particles, in µg/m3, the fraction selected by the inlet impactor.


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Fig. 26. LVS schematics and impactor view (1 – impactor nozzle; 2 – impactor plate; 3 – condensing cavity; 4 – filter holder) Measuring procedure: - the quartz filter must be prepare by drying into controlled atmosphere for 24 hours, then is to be weighted with a 0.00001 g precision and the filter weight must be noted - the filter is inserted into the impactor filter holder and into the impactor head - the impactor is connected to the sampling pump - from the menu the following data must be selected: volume 2.3 m3/h, sampling period 24 hours and start. - the instrument will stop the sampling after 24 hours - when the sampling is finished the filter is collected and weighted again. - the difference between filters weights represents the collected particles in 24 hours. Diving the result by 24 we will obtain the particle concentration in ambient air. mPMx 106 C PMx [ g / m3 N ] VN 24 where mPMx is the particle mass and VN sampled air volume


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TSI DustTrack DRX 8533 instruments. Principle and operation mode. The DUSTTRAK Model 8533 is a desktop instrument. The DRX models are in the ability of the DRX advanced models to measure size fractions of the sampled aerosol in addition to making a mass based photometric measurement. This employs a patent pending method to simultaneously measure size segregated mass fraction concentrations (PM 1 , PM 2.5 , Respirable/PM 4 , PM 10 /Thoracic, and TPM) over a wide concentration range (0.001–150 mg/m 3 ) in real time. This method combines a photometric measurement to cover the mass concentration range and a single particle detection measurement to be able to size discriminate the sampled aerosol. Aerosol is drawn in to the sensing chamber in a continuous stream using a diaphragm pump. Part of the aerosol stream is split ahead of the sensing chamber and passed through a HEPA filter and injected back in to the chamber around the inlet nozzle as sheath flow. The remaining flow, called the sample flow passes through the inlet entering the sensing chamber. Here, it is illuminated by a sheet of laser light. This sheet of laser light is formed from a laser diode. First, the light emitted from the laser diode passes through a collimating lens and then through a cylindrical lens to create a thin sheet of light. A gold coated spherical mirror captures a significant fraction of the light scattered by the particles and focuses it on to a photodetector.

Fig. 27. TSI DRX 8533 principle of operation Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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The instrument is very easy to operate, the main steps are: - start the instrument - select MAIN – RunMode and then select the desirable mode to run the measurement. It is possible to choose the sampling time, pauses between different sampling episodes, frequency of the sampling, a.o. - on the main screen pres “Start” and the measuring begins - the data is recorded automatically and also recorded on an external computer

Fig. 28. TSI DRX 8533 main screen

Fig. 29. TSI DRX 8533. Example screen for graphical view of the measurement.


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3.7. Differential Optical Absorption Spectroscopy (DOAS). DOAS is a method to determine concentrations of trace gases by measuring their specific narrow band absorption structures in the UV and visible spectral region (Platt and Perner, 1983; Platt, 1994). A typical DOAS instrument consists of a continuous light source, i.e. a Xe-arc lamp, and an optical setup to send and receive the light through the atmosphere (Platt, 1994)]. It is also possible to use the sun or scattered sun light as light source. The typical length of the light path in the atmosphere ranges from several hundred meters to many kilometers.

Fig. DOAS principle After its path though the atmosphere the light is spectrally analyzed and the concentrations are derived. In the atmosphere the light of the lamp (I0(l)), undergoes extinction processes by air molecules (sRay(l )) and aerosols (sMie(l)), turbulence (T(l)), and absorption by many trace gases with the concentrations Ci and absorption cross sections si(l). The light intensity from a path of length L can be described by:

I

I 0 ( ) exp(

i

( ) Ci L

Ray

( )

Mie

( )) T ( )

The task of any spectroscopic method in the atmosphere is to separate these effects in order to derive the concentrations of trace gases. DOAS overcomes this problem by separating the trace gas absorption cross sections into low and high frequency parts by specific numerical filtering methods

s (l )

s B (l )

s ' (l )


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Fig. 30. Separation of broad and narrow part of absorption By applying the same filtering routine to I(l), a new I’0(l) is defined which contains the low frequency part of the spectrum (the extinction and turbulence effects, as well as all broad band gas absorption structures). I '0 (l ) I (l )

I 0 (l ) exp[ S ( s B i (l ) Ci L) sR (l ) sM (l )] T (l ) I '0 (l ) exp( S ( s'i (l ) Ci

L)

The exponential term in the above equation now only contains narrow absorption structures, which are used by DOAS to determine the trace gases concentrations. By calculating the differential absorption the concentration, Ci can be derived: D ' ln Ci

I( ) I '0 ( ) D' 'i ( ) L

The following figure shows differential absorption cross-section for some of the trace gases that can be measured by DOAS. DOAS can also measure concentrations of many different trace gases, most of them involved in photochemical smog formation: O3, NO2, HCHO, HONO, H2O, NO3, SO2, NH3, H2S, benzene, toluene, xylene and several aromatic hydrocarbons


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Fig. 31. Differential absorption cross-sections of some trace gases absorbing in the UV/VIS wavelength region. On the right axis the detection limits of the trace gases is listed together with the typical light path lengths used to measure them


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SANOA The SANOA multi-gas open path analyzer is designated as an equivalent method EQOA – 0400 – 137 for the measurement of Ozone, EQSA – 0400 – 138 for the measurement of SO2; EQNA – 0400 – 139 for the measurement of Nitrogen Dioxide as defined in CFR 40, Part 53 when operated according to this manual under the following conditions: 1. Optical monitoring path length: 27 to 500 m 2. Concentration range 0-500 ppb 3. Ambient temperature range –30°C to + 45 °C 4. Measurement cycle time: 3 min 5. Line voltage 110 ± 22 VAC, 50 Hz or 220 ± 44 VAC, 60 Hz The equipment is composed of four separate units: 1 - the projector or light source, 2 - the measuring box or receiver which registers the spectrum of light, 3 - the control unit, a computer running the dedicated VisionAIR software, used by the user to control the instrument and to visualize the measurement results. 4 - the interface unit which supplies electrical power (24 V DC) to the receiver. The link between the receiver and the control unit is carried out by a serial link of the RS422 type, through the interface unit. This projector is the light source. It is composed of a 500 mm focal length telescope F/5 aperture equipped with a high-pressure Xenon vapor lamp. Thanks to this architecture, a light beam of very little divergence is obtained over a broad spectral range. The mirror is fitted with a balland-socket joint and can be orientated using micrometer screws, making site and azimuth adjustment operations very easy. The lamp's high voltage supply system is integrated into the stand of the projector, in a tight container which contains the ignition device as well as the protection against micro power cuts. The receiver is the core of the instrument. It is equipped with a tracking mirror whose orientation is controlled by software, which searches for the location of the projector in order to direct their light beam into the entrance slit of the spectrometer. The receiver works on a spectral band of 200 up to 375 nm. The control unit is a Windows-based microcomputer, located away from the weather, and ensures the configuration of the instrument, download and storage of the spectra, data processing and display. In the remaining of this manual the terms “control unit” are used instead of “the PC running the VisionAIR software that is linked to the receiver via the interface unit”. SANOA SET-UP 1. The monitoring path must be free of any obstacle 2. Distance of obstacles: 90% of the monitoring path must be more than 1 meter off the ground and/or any obstacles and 80% of the monitoring path must be between 3 and 15 meters off the ground and/or any obstacles


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3. Distance from an isolated obstacle: In case there would be an obstacle near the monitoring path, the distance between the obstacle and the light beam (b) must be at least two times greater than the height that the obstacle protrudes above the monitoring path (a).

Fig. 32. Installation location recommendations The adjustment of the projector consists in aiming its light beam to the tracker of the measurement unit. To do this: (1) Direct the projector beam in the direction of the receiver. (2) Fine adjust the direction of the projector beam using the adjustment screws of the projector’s rear mirror. (3) Adjust the lamp position to change the beam divergence if necessary (4) Repeat steps 2 and 3 if necessary All these operations are made considerably easier if the light beam footprint emitted by the projector is visible i.e. if the adjustment is made at night. A dark night is not required: right after sunset or before sunrise is enough to get a good vision of the projector beam. Right before sunrise is a good period since it allows the other operations Loosen the four azimuthal maintaining screws slightly (item E), in order to be able to rotate the projector around the vertical axis. Do the same for the four screws (items A and B) which maintain the site of projector (up and down movement), Move the body of the projector in order to place the light footprint roughly towards the receiver. Tighten again the four azimuthally maintaining screws firmly (item E), Tighten the two lower site maintaining screws (item A), then the two upper screws (item B).


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Fig. 33. Projector adjustments The VisionAIR software package, developed by Environnement S.A., is the interface between the operator and the SANOA instrument. This unique software carries out the three basic functions of the instrument operation, which are the system configuration management (3.5.3. – VisionAIR Configuration), the acquisition and the analysis of the spectra (3.5.4 VisionAIR Measure) coming from the instrument as well as the consultation of the measurement results (3.5.5 - VisionAIR Consultation). The VisionAIR software package is protected by a hardware key which must be installed at all times on the parallel port of the control unit. This hardware key contains the definition of the system as it was ordered (number of parameters measured by the system). These three programs are named by the installation program: VisionAIR XYZ Configuration; VisionAIR XYZ Measure; VisionAIR XYZ Consultation, where X.YZ is the version of the VisionAIR software package that is being used. More details are to be read into the SANOA technical manual.

Fig. 34. Example of the UV-VIS spectra acquisition Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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3.8. AIRPOINTER The AIRPOINTER is world’s first „out-of-the-box plug and play“compact multi gas air quality monitoring system. Measure anywhere you want due to very compact dimensions and measure a wide variety of pollutants in a modular platform - with up to seven ambient air analyzers measuring CO, NO/NO2/NOX, O3, SO2 , H2 S, VOC and new: PM10 and PM2.5 as well as a variety of Indoor Air Quality Sensors. Tailor it to your specific needs with our unique SIP sensor interface platform. The AIRPOINTER is type approved by TUEV according to the European standards for air quality monitoring. The AIRPOINTER is type approved according to the European Norms for the gases O3, CO, SO2 and NO/NO2/NOX. The builtup of the AIRPOINTER is presented in figure 35.

Fig. 35. AIRPOINTER internal components (www.recordum.com) The AIRPOINTER main features are: Shelter made of double-wall coated aluminum plate providing excellent isolation against temperature and electrical radiation. Two standard cylinder locks for main door and maintenance access door, which could also be part of a key system. Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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Internal air conditioner and temperature management system providing optimized energy consumption. Rugged, unobtrusive and burglar proof design to allow applications in public rooms. Analyzing modules on drawers for easy expansion of the system as well as good serviceability. Cables and tubing protected against mechanical damage. Internal zero air supply for periodical zero check or calibration. Optional spas gas supply available. The data management system allows implementation of additional monitoring devices including particulate matter monitors like the TEOM/FDMS or a Beta-gauge. AIRPOINTER main components: SO2 unit, ultraviolet fluorescence O3 unit, ultraviolet photometry CO unit, non-dispersive infrared (NDIR) NO/NO2/NOx unit, chemiluminescence PM10/PM2.5 unit, nephelometry VOC unit, photoionisation (PID) Internal air conditioning unit Integrated meteorological sensors Internal data logger, GPRS module and wireless module for data management and instrument control An internal zero air supply for the automatic or manual zero check is standard in the AIRPOINTER ambient gas modules (CO, NOX/NO/NO2, SO2/H2S, O3) can be optionally equipped with span check system integrated on their drawer. The CO analyzing module is checked by small user refillable calibration bottle mounted at the module angle. An internal permeation system is used with Nitric Oxide and the Sulfur Dioxide/Hydrogen Sulfide analyzing module. This system applies permeation tubes which contain pure gas under high pressure. At a constant temperature a specific amount of gas is flowing across a membrane at the permeation tube, which is mixed with a constant flow of zero air. This enables a precise and reliable span gas supply. The Ozone analyzing module is checked by an ozone generator. In this generator a constant flow of zero air is mixed with Ozone produced by an UV-lamp. All function checks are stored in the internal database of the AIRPOINTER. At any time the user has access to this data. The operation of the AIRPOINTER is very simple and is done thru a PC or laptop. The steps to start-up and operate the AIRPOINTER are: 1. Mounting (Take care of the required ventilation clearance and maintenance space) 2. Mount the sample inlet and further equipments: GPRS antenna, wind sensor, and sample inlet for the particle sensor, on top or at the side of the airpointer


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3. Boot up the airpointer (airpointer boots up, when the internal temperature is above 5° C) 4. Connect your Laptop with the delivered cross patch cable with the LAN connector in the maintenance door. Boot up the laptop and con gure your internet connection 5. Connect your Laptop with the airpointer via the recordum portal (portal.recordum.com) 6. Open the User Interface on your PC 7. In the User Interface deviations of the measurement values outside the chosen warn and failure limits are shown 8. Wait till all warn and fail signs cease (this should require 15 to 30 minutes depending on the con guration). Then the green LED in the maintenance door lights and the airpointer is ready for operation 9. Perform a leak check. 10. Perform a sample ow check. 11. Leave the maintenance mode and start the measurement

Fig. 36. View of the AIRPOINTER user interface The instrument is very easy to control thru the user interface (accessible by internet browser) and a complete description will be provided during the training, including the AIPOINTER operational manual.


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3.9. Meteorological data and AQM station setup The next figure shows a scheme of a set-up of such a measuring station. The measuring gas suction hoods and different meteorological measuring instruments are installed on a 10 m high altitude. The management and working methods are respecting the international standards SR EN ISO/CEI 17025:2005. In addition to the instruments for the specific measurement of pollutants there are numerous other instruments for the recording of meteorological parameters such as wind direction and wind speed, temperatures, global radiation, duration of rain and bedewing, amount of rain etc., as well as an electronic controlled computer, to record, calculate and memorise the values. Some measuring stations work with direct data transmission to a central computing station.

Fig. 35. Set-up of the sampling system of an air quality station with air suction through tubes and with calibration gas switching

Fig. 36. View of the meteorological sensors Investing in your future! Romania-Republic of Serbia IPA Cross-border Cooperation Programme is financed by the European Union under the Instrument for Pre-accession Assistance (IPA) and co-financed by the partner states in the programme. For more information, please access www.romania-serbia.net

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Fig. 37. View of the mobile AQM Laboratory and the acquisition print screen Literature: Artiola, J. et al. (2004), Environmental Monitoring and Characterization, Elsevier, 2004 Baumbach, G. (1992). Luftreihaltung – 2 auflange, Springer Verlag, Berlin, Germany Colls, J. (2002). Air Pollution – Second Edition, Spon Press, ISBN 0-20347602-6, UK EEA, (2008). EEA technical report, no7/2008, Annual European Community LRTAP Convention emission inventory report 1990–2006, EEA office for official publication, Copenhagen Godish, T. (1997). Air Quality, CRC Press LLC, ISBN 1-56670-231-3 Boca Raton Godish, T. (2004). Air Quality – 4 th Edition, CRC Press LLC, ISBN 0-203-49265-X, Boka Raton, Florida Koppmann, R. (2007). Volatile organic compounds in the atmosphere, Blackwell Publishing Ltd, ISBN 9781-4051-3115-5, Singapore Platt, U., and D. Perner, (1983). "Measurements of atmospheric trace gases by long path differential UV/visible absorption spectroscopy", in Optical and Laser Remote Sensing, pp. 95-105, Springer Verlag, New York. Platt, U., (1994). "Differential optical absorption spectroscopy (DOAS)", Chem. Anal. Series, 127, 27 - 83, Popescu, F. et al. (2009). Ambient air quality measurements in Timisoara. Current situation and perspectives, Journal of Environmental Protection and Ecology, 10 (1), 2009, ISSN 1311-5065 Raub, J. A. et al. (2000). Carbon Monoxide Poisoning - a Public Health Perspective. Toxicology (145):1-14, 2000 Raub, J. A. (2002). Carbon Monoxide and the Nervous System. Neuroscience and Biobehavioral Reviews, 26(8), 2002, ISSN 925-940 Schnelle, K.B & Brown, C.A. (2002). Air pollution control technology handbook, CRC Press, ISBN 0-84939588-7, Boca Raton. Florida TSI. (2010). Type of particles. Technical document, TSI Incorporated, www.tsi.com Zchicheng, W. et al. (2002), Design on Monitor system of Sulfur Dioxide Concentration by UV. Fluorescence Method, Preceedings of the SPIE vol. 4927


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NOTES


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