Jan 3, 2001 - Determination of Health Risk from Indoor Air Quality ⦠... dwellings in developed countries, the level of indoor air pollution is very low because ...
MOH
WHO
HEALTH RISK ASSESSMENT OF INDOOR AIR QUALITY (MOG/HSE/4.3/001, AC.01.03.01.AW)
ULAANBAATAR, MONGOLIA 2003-2004.
PHI
THIS STUDY WAS CONDUCTED UNDER THE AUSPICES OF THE WORLD HEALTH ORGANIZATION, WESTERN PACIFIC REGIONAL OFFICE (WHO/WPRO) IN MANILA, PHILIPPINES. ACKNOWLEDGMENTS The Ministry of Health is grateful to: Dr.Hisashi Ogawa, Regional Adviser in Healthy Settings and Environment, WPRO, Mr. Robert Hagan, WR, Mongolia and Dr. Salik Ram Govind, Public Health Specialist, WHO, Mongolia for their kind support and technical assistance. We would like to express our sincere gratitude to Prof.J.Spickett, Curtin University of Technology and Andrew Baker, WHO STC and Dr. Reijo Salmela, Medical Officer, WHO, Mongolia for their invaluable contribution for successful implementation of the project.
CONSULTANTS:
Prof. Jeffrey Spickett and Andrew Baker, Curtin University of Technology, Perth, Western Australia
STUDY TEAM:
Dr.G.Enkhjargal, MD, Senior Research Officer, Public Health Institute, Mongolia Dr.P.Enkhtuya, MD, PhD, Researcher & Statistician, Public Health Institute, Mongolia Dr.N.Suvd, MD, Researcher, Public Health Institute, Mongolia N.Sod-Erdene, Researcher, Public Health Institute, Chemist and Lab technician, Mongolia O.Baigal, Chemist & Lab technician, Public Health Institute, Mongolia Dr.N.Jargalsaikhan, MD, PhD, DSc (Med), Vice director of Policy & Coordination Division, MOH, Mongolia Dr.G.Soyolgerel, MD, Officer in charge of Child Health, MOH, Mongolia Randy VS, Research Manager, UNDP Project
SUPERVISORS:
Dr.Sh.Enkhtsetseg, MD, PhD, Officer in charge of Public Health, MOH, Mongolia Dr.B.Burmaa, MD, PhD, DSc (Med), Officer in charge of Medical Science Policy , MOH, Mongolia 2
TABLE OF CONTENTS Page No. CHAPTER 1. INTRODUCTION……………………………………………………
5
Background ……………………………………………………………………………… 5 Indoor air quality in Mongolian Dwellings ………………………………………………. 6 Potential Air quality indicators of Interest ………………………………………………. 9 Related studies in Ulaanbaatar …………………………………………………………… 11
CHAPTER 2. METHODOLOGY …………………………………………………… 13 Background ……………………………………………………………………………… 13 Cross sectional study(Prevalence) …………………………………………………….
13
Case control study ……………………………………………………………………… 14 Air quality monitoring …………………………………………………………………… 17 Air Tightness Testing …………………………………………………………………….. 21
CHAPTER 3. RESULTS ……………………………………………………………… 23 Cross sectional study …………………………………………………………
23
Case control study ……………………………………………………………
30
Indoor air quality ………………………………………………………………. 40 Determination of Health Risk from Indoor Air Quality ………………………
46
CHAPTER 4. AIR TIGHTNESS STUDY OF DWELLINGS …………………… 50 CHAPTER 5. DISCUSSION ………………………………………………………… 53
CHAPTER 6. CONCLUSIONS AND RECOMMENDATIONS…………………… 57
REFERENCES …………………………………………………………………………. 59
APPENDIX 1. CROSS SECTIONAL QUESTIONNAIRE …………………………. 61
APPENDIX 2. CASE CONTROL QUESTIONNAIRE ……………………………. 66
3
APPENDIX 3. RAW AIR QUALITY MONITORING DATA ………………………71
APPENDIX 4. TABLES OF ASSOCIATION BETWEEN CONTENTS OF CO&PM10 AND RESPIRATORY SYMPTOMS ………………………………………………
82
APPENDIX 5. COMPLETED BLOWER DOOR TEST FORM ………………….
84
APPENDIX 6. CALIBRATION DATA FOR BLOWER DOOR ………………….. 85
4
CHAPTER 1. INTRODUCTION Background
Indoor air quality has increasingly been attracting attention worldwide. In most dwellings in developed countries, the level of indoor air pollution is very low because there are controls on the design, ventilation and construction of buildings. However, if ventilation of rooms is poor, or household appliances are faulty, pollution can build up to levels which may be detrimental to human health. In rapidly developing and industrializing countries, the major air pollution problem is typically high levels of smoke and sulphur dioxide (SO2) arising from the combustion of sulphur-containing fossil fuels such as coal for domestic and industrial purposes. The other major threat to clean air is also posed by increasing traffic emissions. Petrol and dieselengined motor vehicles emit a wide variety of pollutants, principally carbon monoxide (CO), oxides of nitrogen (NOx), volatile organic compounds (VOCs) and particulates (PM10), which have an increasing impact on urban air quality. Indoor air pollution may have many sources in a dwelling, and indoor air quality can vary widely. A significant source of indoor air pollution is the burning of fuels, such as coal, wood, biomass or gas, in stoves. If the stove is poorly designed, inefficient or defective, incomplete combustion with the release of carbon monoxide (CO) may result. Carbon monoxide also builds up indoors when people smoke cigarettes. In the absence of good ventilation, the more confined the space, the greater the risk to those exposed. Particulates are seen by many as one of the most critical air pollutants, and some estimates have suggested that particulates are responsible for up to 10,000 premature deaths in the United Kingdom each year. (UK Department for Environment, Food & Rural Affairs and the Devolved Administrations 2003) The extent to which particulates are considered harmful depends largely on their composition. Very fine particulates can penetrate deep into the lung and cause more damage, as opposed to larger particles that may be filtered out through the airways’ natural mechanisms.
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Indoor air quality in Mongolian dwellings
Over the past two decades, Mongolia has become increasingly urban in character. In 2000, 57% of the population lived in urban areas. In the period of 1995 to 2000, Ulaanbaatar attracted more than 75,000 migrant families from the regions, and the trend is similar within provinces (Aimag), with the migration also being directed towards their urban centres.
Population has been increasing at an annual average rate of 1.4%.
Accordingly, Mongolia is experiencing pressure on the environment and public health from an increasing demand for basic public health services due to the growth in population and urbanization. Strain has been placed upon the ability of the City of Ulaanbaatar to provide the necessary infrastructure (water supply, sanitation, electricity, heating and apartment accommodation) for the influx of populations from outside. While some are fortunate enough to be able to obtain apartment accommodation, most rely upon their traditional housing (Gher) or fabricate a structure within which to house themselves. Recent estimates (Tserenpurev, T. 2003, pers com) suggest that between 80,000 and 100,000 households now inhabit the fringes of Ulaanbaatar City in various classes of semi-permanent dwelling, consisting of two main types - the traditional Mongolian Gher and the individually constructed houses. The consequence of these settlements is that there are upwards of 100,000 sources of air emissions from coal fired stoves in these fringe dwellings, creating a potentially significant environmental health impact from deteriorating outdoor (ambient) and indoor air quality in the city, particularly in winter. The Gher The traditional Gher is a portable circular wood framed dwelling covered in multiple layers of wool felt. It is found across the country-side and more recently on the fringes of the cities across Mongolia, as urbanization continues. The Gher has only two openings, the door and a ventilation flap in the roof. It consists of a single “room” within which washing, cooking, eating and sleeping all take place. Heating is provided from a stove, located at the centre of the Gher with a chimney to direct the flue gas through the central roof vent. The stoves are of variable quality and efficiency. The fuel used is usually coal (in Ulaanbaatar) wood or biomass (in other parts of the country). A Gher can house (sleep) an entire family and relatives for extended periods (anecdotal advice suggests that a Gher can house upwards of 17 persons) (Narantuya, L. 2003, pers com). The Gher is 6
very efficient in enduring the severe Mongolian winters (which can reach minus 25-30 degrees Celsius) as the closed felt lining, limited openings and stove provide defence against the extreme cold. (Picture 1). Picture 1.
In summer the Gher may be well ventilated by rolling up the external lining and opening the roof vent providing indoor air circulation and replacement. In winter, the Gher is essentially a sealed chamber. Therefore the indoor environment potentially suffers from extremely poor ventilation resulting in; •
Potentially high levels of smoke (particulates)
and chemical products of
combustion (such as sulphur dioxide); •
Increased carbon monoxide from the poor quality of the stoves and their resultant poor combustion and decreased oxygen level;
•
elevated humidity and carbon dioxide as a result of the respiration of the inhabitants; and
•
intensified effects of passive smoking for the inhabitants.
No water supply, electricity or internal sanitary facilities exist in Ghers, with pit latrines being used outside.
7
The House The house is extremely variable in the quality of construction and the material from which it is built, depending upon the means of the owner. Typically, a house will be a wooden block structure, wind proofed with plastic sheeting, thermally insulated by the thickness and materials of its walls. Ventilation is solely through its windows and doors, which remain closed most of the time in winter to keep out the bitter cold. Variations include thick walled brick structures, which may have double glazing for added thermal insulation. Floors may be wooded or concrete, covered in carpet or vinyl. Walls may be plastered and painted or covered with wall vinyl. Supply of water, electricity and sanitation is usually non-existent. There are no uniform building codes or building inspection of these structures. In common with all variants is the absence of any fixed ventilation. In building a house, the owner attempts to emulate the benefits of a Gher (an insulated wind proof haven in winter). A house has a greater internal volume than a Gher and several rooms. Heating and cooking is provided from the same stoves as are found in the Gher. Similar issues regarding air quality as for the Gher are expected to be experienced. However due to the larger internal volume and division into rooms, it is reasonable to expect a lower severity of contamination of the indoor environment in a house (Picture 2).
Picture 2.
The Apartment Apartments are located in multi-story blocks, and are usually of concrete and brick construction. They are provided with central water supply and heating, electricity and
8
sewered sanitary facilities.
They are divided into a living area, kitchen, combined
bathroom/toilet and a number of bedrooms. Most rooms have double glass windows, which are closed during winter to maximize the benefit of the central heating (reticulated hot water from boilers circulating through convection heaters). Most apartments have rudimentary passive ventilation fitted only to the kitchen area and the bathroom/toilet. This ventilation consists of an outlet grill of approximately 150mm x 80mm, ducted to outside air through the wall of the apartment, relying purely on convection for movement of air. No active inlet ventilation is usually provided. Floor, wall and window are covered by carpets, curtains, floor and wall vinyl or painted finishes. Cooking is typically done on an electric or bottled liquified petroleum gas (LPG) stove. As with the house and Gher, the number of inhabitants in an apartment may be quite high (picture 3).Picture 3.
Potential Air Quality Indicators of Interest Sulphur Dioxide (SO2) Sulphur dioxide is an acidic gas which in ambient air can affect human health, particularly in those suffering from asthma and chronic lung diseases. The principal source of this gas is power stations burning fossil fuels (coal) which contain sulphur. Major SO2 problems now only tend to occur in cities in which coal is still widely used for domestic heating and in power stations, as in Ulaanbaatar. This indicator was monitored in the indoor air of a range of dwellings for the purposes of this study.
9
Health Effects Even moderate concentrations may result in a fall in lung function in asthmatics. Tightness in the chest and coughing occur at high levels, and lung function of asthmatics may be impaired to the extent that medical help is required. Sulphur dioxide pollution is considered more harmful when particulate and other pollution concentrations are high.
Particles (PM10) Airborne particulate matter varies widely in its physical and chemical composition, source and particle size. PM10 particles (the fraction of particulates with diameters less than 10 µm are of major current concern, as they are small enough to penetrate deep into the lungs and so potentially pose significant health risks. Larger particles meanwhile, are not readily inhaled, and are removed relatively efficiently from the air by sedimentation. The principal source of airborne PM10 matter in Mongolian dwellings is smoke and dust (ash) from the cooking and heating appliances. PM10 was monitored in the indoor air of a range of dwellings for the purposes of this study Health Effects Fine particles can be carried deep into the lungs where they can cause inflammation and the worsening of the condition of people with heart and lung diseases. In addition, they may carry surface-absorbed carcinogenic compounds into the lungs.
Carbon Monoxide (CO) Carbon monoxide is a toxic gas which is emitted into the atmosphere as a result of combustion processes, especially where that process is inefficient or the combustion incomplete. It survives in the atmosphere for a period of approximately one month but is eventually oxidized to carbon dioxide (CO2). CO was monitored in the indoor air of a range of dwellings for the purposes of this study Health Effects This gas prevents the normal transport of oxygen by the blood. This can lead to a significant reduction in the supply of oxygen to the heart, particularly in people suffering from heart disease.
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Nitrogen Dioxide (NO2) Nitrogen oxides are formed during high temperature combustion processes from the oxidation of nitrogen in the air or fuel. The principal source of nitrogen oxides - nitric oxide (NO) and nitrogen dioxide (NO2) collectively known as NOx - in indoor air are the coal or gas fired stoves commonly in use in Ulaanbaatar. NO2 was not monitored for the purposes of this study, due to limitations in the availability of suitable monitoring equipment and budgetary constraints Health Effects Nitrogen dioxide can irritate the lungs and lower resistance to respiratory infections such as influenza. Continued or frequent exposure to concentrations that are typically much higher than those normally found in the ambient air may cause increased incidence of acute respiratory illness in children. Related Studies in Ulaanbaatar A descriptive study (Damdinsuren.À, 1968) looked at some environmental parameters such as temperature variation, relative humidity and carbon dioxide, indoor and out between seasons in Ghers. The principal findings were the temperature differential between indoor and outdoor temperatures in winter (up to 48 degrees Celsius) and the temperature gradient from 20 degrees Celsius to less than 6 degrees, with anecdotal evidence that this could go well below freezing. The study also highlights that the indoor temperature profile is extremely variable with the maximum temperatures being reached soon after fuelling the fire, and rapid decay thereafter until refuelling. This parameter may represent a very important causal factor in respiratory conditions in the inhabitants, however was outside the scope and budget and thus not included in the current study. A study into indoor air quality and health from domestic stoves (N.Saijaa et al, 2000) indicates that the following ranges of contaminant concentrations may typically be found in Gher: SO2 0.0013 to 0.102 (as mgm-3) NO2 0.019 to 0.191 (as mgm-3) CO
0.2 to 23.2 (as mgm-3)
TSP 0.0074 to 0.154 (as mgm-3)
11
A study supported by the World Bank (Bulgan, 2002) has demonstrated that the emissions of contaminant gases and particulates vary widely, dependent on the quality of the fuel (coal) and design and condition of the stove. Work is underway currently to improve the design characteristics of the typical domestic stove to improve combustion efficiency, reduce fuel usage and reduce emissions from them. Mongolian houses have unvented combustion appliances in the living areas of the home.
These appliances leak combustion gases and require a minimum amount of
ventilation to remove indoor pollutants. The threshold will vary with the level of indoor pollutant emissions and with outdoor pollution. This testing was done to determine if this threshold is being attained for current Mongolian houses. A correlation between indoor pollutant levels and air tightness would indicate this phenomenon.
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CHAPTER 2. METHODOLOGY
Background The study was conducted in two phases. Phase 1 consisted of a cross sectional study to determine the prevalence of respiratory diseases in children between 2 and 8 years of age, and describe some of the environmental factors to which those children are exposed (for example type of residence, type of heating used). Phase 2 was a case control study whereby the researchers sought to establish the extent to which differences in the amount of exposure to indoor environmental factors in dwellings in Mongolia can explain the risk of the development of bronchitis in winter. Indoor air quality monitoring for indicators of products of combustion (SO2, CO and suspended particulates from smoke) and activities within the dwelling (suspended particulates, temperature, humidity) was undertaken.
Cross Sectional (Prevalence) Study Aim of the Study •
To determine the prevalence of asthma, bronchitis and other respiratory symptoms in children between 2 and 8
years of age in two districts of
Ulaanbaatar; •
To determine the prevalence of asthma, bronchitis and other respiratory symptoms in different types of dwellings typically used in those districts;
•
To identify factors that may affect the indoor air quality in three different types of dwellings; and
•
To refine the questionnaire to be used in the case control (Phase 2) part of the study. Methodology
A cross sectional study was chosen as appropriate to achieve the aims. A letter, explaining the nature of the study was sent or given to parents to ask them if they would like to participate in the study. Those who agreed to participate were asked to sign a consent form. Those participating were given a structured interview by inspectors from the 13
city and state health inspectorate, and some personnel from the Public Health Institute, who completed the questionnaire and returned it to the researchers. The study was carried out in two districts of Ulaanbaatar City, Mongolia, namely Sukhbaatar and Bayangol Districts. The participants were children aged between 2 and 8 years old. The group was divided equally between the Districts, and was further subdivided as far as practicable equally for age, gender and type of residence. Confirmed diagnosis by the Family Doctors of bronchitis, asthma and other respiratory symptoms over the last 12 months was recorded by the inspectors. Sample Size, Location, Type of House and Timing of Survey A sample size of 500 children, 2 to 8 years of age, were surveyed in the Sukhbaatar and Bayangol Districts of Ulaanbaatar. The sample was divided equally by district (n=250) and the study conducted such that approximately equal numbers of males and females by age by type of house were studied within both districts. The questionnaire was administered as a structured interview by inspectors in the district from 13 January and 23 February 2003. The inspectors completed the questionnaires and returned them to the researchers. Questionnaire A modified questionnaire of the American Thoracic Society (1978) was used. Questions regarding age, gender of the child, education of parents, family income, health status of parents and siblings, parental and maternal smoking, type of heating, ventilation, cooking, floor and wall covering were included.
The questionnaire is attached in
Appendix 1.
Case Control Study For the purposes of Phase 2 of the study, a case control study of children in the age group of 2 to 8 years old was undertaken, examining cases of chronic bronchitis. Aim of the Study •
To determine the extent to which differences in the amount of exposure to indoor environmental factors can explain the risk of the development of bronchitis in winter;
14
•
To determine the extent to which other characteristics of the child, his or her parents/guardians and siblings, modify the relationship between indoor air pollutants and bronchitis. Factors considered include:
•
-
parents educational level
-
type of house; and
-
personal susceptibility factors;
To determine the influence of certain house characteristics on the risk of bronchitis such as type of heating, maternal and paternal smoking, type of floor covering; and
•
To determine the extent to which the house characteristics influence the concentrations of indoor air pollutants. Methodology A case control study was chosen as appropriate to achieve the aims of the study. The
study was carried out in the entire urban area of Ulaanbaatar, Mongolia, consisting of 8 Districts. The participants were children aged between 2 and 8 years old. The age group was restricted for cases and controls by defining an eligible range of age and hence they were not matched for age. Sample group numbers were not proportioned by the type of dwelling or location.
One hundred and twenty family hospitals were identified in
Ulaanbaatar, from which 75 were selected using random number selection techniques. A family doctor at the selected hospital identified a single case and single control purely on whether the subject met the requirements of a case or control as described below. This enabled the study to determine whether dwelling type or location were risk factors or confounding variables. The cases were children who were -
diagnosed with bronchitis by the family doctor within the last month prior to the study; or
-
diagnosed with a current episode of bronchitis by their family doctor at the time of the study.
The controls were children, selected by the same family doctor, who had been diagnosed with conditions other than bronchitis or other respiratory disorders, e.g. injury or gastroenteritis for the same periods. 15
The family doctors identified the cases and controls presenting at their hospitals current with, or within one month prior to the commencement of the study. A letter, explaining the nature of the study was sent or given to parents to ask them if they would like to participate in the study. Those who agreed to participate were asked to sign a consent form. Those participating were given a structured interview by their family doctor, who completed a questionnaire and returned it to the researchers. Modified Questionnaire The questionnaire utilized in the cross sectional study (a modified questionnaire of the American Thoracic Society, 1978) was modified based on the experience of its application in that study. Where questions relating to structures, appliances and behaviour were found to be irrelevant to the Mongolian way of life, they were deleted. Questions relating to respiratory diseases and conditions other than that under review (bronchitis) were also deleted. Questions that enabled the researchers to assess the severity of the condition of the cases were added, as were questions which enabled the researchers to determine the acute or chronic nature of the condition. Questions regarding age, gender of the child, education of parents, health status of parents and siblings, parental and maternal smoking, type of heating, ventilation, cooking, floor and wall covering were included. The questionnaire is attached at Appendix 3. Sample Size, Location and Timing of Survey Extrapolating from published data for standard errors and correlation structures (Menezes AM, 1994), it may be estimated that there will be a power of 90% to detect as significantly different from the null hypothesis (0.05), a true odds ratio of 2.5 for the association between respiratory bronchitis and binary exposure to air pollutants. Assuming 20% prevalence of bronchitis in Ulaanbaatar (from the cross-sectional study), the sample size with 80% power of the two-tail test at the 0.05 level of significance will be 75 cases and 75 controls. Thus a sample size of 75 cases and 75 controls was selected. Administration of the questionnaire by the family doctors was conducted as a structured interview between mid-December 2003 and the end of January 2004, the coldest winter months in Ulaanbaatar when temperatures typically reach minus 20OC to minus 25 OC.
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Air Quality Monitoring Aim of the Study •
To evaluate levels of exposure to indoor air pollution in dwellings;
•
To evaluate the association between exposure to indoor air pollution and respiratory diseases in children;
•
Specifically, in conjunction with the questionnaire, to determine the extent to which differences in the amount of exposure to contaminants of indoor air quality can explain the risk of development of bronchitis in children in winter;
•
Sulphur dioxide (SO2) as an indicator of pollution from the combustion of coal;
•
Carbon monoxide (CO) as an indicator of incomplete combustion of fuel and inefficient waste gas exhaust;
•
Respirable particulate matter (PM10) as an indicator of smoke from opening the stove, smoking and/or dust from indoor activities and the characteristics of the house; and
•
To determine the extent to which the house characteristics and appliances influence the concentrations of indoor air pollutants. Methodology Small, portable battery operated aspiration pumps, sampling through colorimetric
long-term time weighted average (TWA) tubes (for SO2 and CO), and a PM10 cyclone using pre-weighed filter cassettes for respirable particulates were chosen as appropriate to meet the aims of the study. Traditional wet chemical methods were not considered suitable due to: -
the intrusive nature of the sampling regime;
-
the relatively high risk involved in the use of specialist chemicals and apparatus in the confines of small domestic settings;
-
the lack of stable, reliable power supply in many of the dwellings; and
-
the quality assurance issues associated with sampling protocols, chain of custody and laboratory analytical procedures. 17
The criteria considered in the selection of the instruments, while recognizing that the precision and accuracy of the techniques utilized may not be commensurate with that of laboratory based standards, was as follows. The instruments were to be: (picture 4) •
portable and self contained;
•
able to be left unattended;
•
un-obtrusive (small, relatively quiet, no lights etc)
•
easy to calibrate to internationally accepted standards; and
•
easy to set up, and reliable. Picture 4.
Equipment Mine Safety Appliances (MSA) Escort ELF sampling pumps were chosen as the aspirating pumps appropriate to meet the aims of the study. The Escort ELF sampling pump can be used for personal and area sampling. The pumps have state-of-the-art electronic laminar flow sensors, consisting of a laminar flow element and pressure sensor, providing constant flow (volume) control, with +/- 2.5% regulation of flow rate (from 1 to 3 litres per minute) and automatic compensation for changes in battery voltage, temperature, altitude and sample load. The pumps are approved as intrinsically safe for use in hazardous locations, US
NIOSH certified for coal mine dust sampling and MSHA certified as
intrinsically safe for underground use. The sampling was through two MSA Gemini Twin Port Samplers (see Figure 1) per pump. The sampler is an instrument designed for low flow industrial hygiene measurement of concentrations of gases, vapours and particulates when used with sorbent tubes and 18
cyclone assemblies.
It was used to regulate and maintain the required constant flow
(volume) through the selected sorbent tubes and cyclones.
Figure 1. Indoor Air Quality Sampling System
Sorbent tubes selected for the study were SKC Incorporated’s long-duration color detector tubes which are designed for use with a personal air sampling pumps. Long-duration color detector tubes are used for Time-Weighted Average (TWA) measurements. The tubes were attached to the aspiration pumps which pulled the air sample through the tube at a constant rate during the sampling period. At the conclusion of the testing period, the total volume was calculated (rate [ml/min] x time [min]). Chemical concentration was read directly from the tube. The TWA concentration was readily calculated using the instructions that accompanied the tubes. The tubes selected were Carbon Monoxide CO-5 (SKC #803943) and Sulphur Dioxide SO2-1 (SKC#487338) tubes.
The particulate cyclone was the MSA 10mm cyclone assembly, suitable for sampling the respirable dust fraction (PM10) in the air.
Calibration The MSA Escort ELF sampling pumps have internal secondary standard which calibrates the pump continuously and needs to be checked against a primary standard only once a month, or after 200 hours continuous use. The pumps were calibrated by the external 19
primary calibrator at the commencement of the study, and thereafter re-checked at the midpoint of the study and at its conclusion. The MSA Gemini Twin port samplers required adjustment to match the flow-rate, duration of sampling and the concentration range of the sorbent tubes to the expected airborne concentration of the contaminant of concern (see Figure2, picture 3).
Figure2. Calibrating the Gemini Twin Port Sampler
Sample Size, Location, Timing and Duration of Sampling The dwellings of all cases and controls were monitored for the air quality parameters under review, totalling 150 dwellings. The monitoring took place over the same period as the questionnaire survey, between mid-December 2003 and the end of January 2004, the coldest winter months in Ulaanbaatar when temperatures typically reach minus 20OC to minus 25 OC.
Sampling at each dwelling took place for a minimum of 12 hours
continuously between 8:00 p.m. and 8:00 a.m. (night-time) when maximum inhabitation occurs, the dwelling is configured for keeping out the cold and the heating and cooking systems used (coal fired stoves for Gher and houses, central heating and gas or electric stoves for apartments) were being utilized.
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Picture 5.
Air Tightness Testing of Dwellings Aim of the Study •
To determine if greater air tightness in Mongolian houses would negatively contribute to indoor air quality.
•
to determine the air tightness of selected houses for further knowledge of the nature of indoor pollution in Mongolian houses.
Methodology Air tightness testing was performed in late May 2004 and required 1 week for completion. All 28 selected sample houses were located in the Gher districts of Ulaanbaatar. Samples were selected from the current study to include houses with high and low indoor air quality indicator measurements. Air tightness testing followed the American Society for Testing and Materials (ASTM) (1991) Standard (E779-87) and the Canadian General Standards Board (CGSB) (1986) Standard (149) with some practical protocol exceptions and additions as follows: •
The occupants were asked to show how much of the windows was taped over the winter and these windows were then taped sealed similar to winter.
•
Outdoor pressure was only measured at one point. As the houses all had relatively low air tightness this exercise for increased precision was deemed unnecessary.
A summary of results is included in Appendix 5.
21
The calibration data for the Minneapolis blower door equipment is given in Appendix 6. A new (and calibrated) DG-700 digital pressure gauge was used to measure the house pressure and blower door orifice pressure. The blower door system was purchased from Gray Nelson and Collin Olson at the Energy Conservatory (www.energyconservatory.com).
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CHAPTER 3. RESULTS
3.1 CROSS SECTIONAL STUDY
Sample Demographics
The study covered a total of 500 children aged between 2 and 8. Of them, 49.6% (248) were male and 50.4% (252) were female.
Of the respondents of the cross sectional study, 58.6% (293) were mothers of children, 15.2% (76) were fathers, 6.4% (32) were siblings, and 19.8% (99) were other family members. In terms of the educational level of the parents of children involved in the study, 32.0% of the parents had studied at university level, 20.3% had vocational education, 39.9% had secondary education, 7.8% had primary education, and 18.2% had no education (Table 1).
Table 1. Sample Demographics
Children
n=500 Frequency
Parents (%)
Sex of child: Male Female
Age of child 2 3 4 5 6 7 8
248 252
49.6 50.4
71 71 74 69 69 73 73
14.2 14.2 14.8 13.8 13.8 14.6 14.6
Level of education Mother Primary Secondary Vocational University Father Primary Secondary Vocational University
n=500 Frequency (%)
37 191 115 157
7.4 38.2 23.0 31.4
41 208 88 163
9.2 41.6 17.6 32.6
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Child Health Conditions
Of the children who were involved in the cross sectional study, 9.2% had chest tightness, 51.4% had morning cough, 6.9% had shortness of breath, and 32.5% had morning phlegm in the last 1 month. The results showed that 6.0% (30) of the children’s chests sounded wheezy while doing physical movements or after physical movements in the last 12 months, 4.8% (14) of the children’s chests sounded whistling while not doing physical movements, and 38.9% of the children’s chests sounded wheezy due to colds and coughing. When we asked questions to clarify reasons for chest whistling, 26.4% (44) answered it was because of smoking in the household, 14.9% (25) because of dust, and 88.6% (148) because of colds and coughing. Of those who were involved in the study, 7 children or 1.4% were diagnosed with asthma by family doctors in the last 12 months while 95 children or 19% were diagnosed with bronchitis. Cases of bronchitis were more frequently registered in the winter season, particularly from October to December. Of those who were involved in the study, 9.4% (47) had eczema while 7.4% (37) had itchy skin. One hundred and fifty-eight children, or 31.5% of the children involved in the cross sectional study snored at night and 17.0% of those who snored at night snored frequently. Information on the morbidity of family members showed that 8.0% had eczema and 3.4% had asthma (Table 2). Table 2. Child Health Conditions Indicators CHILD HEALTH Respiratory symptom : Chest tightness Morning cough Shortness of breath Morning phlegm
Chest whistling in the last 12 months
n=500 Frequency (%)
36 200 27 126
9.2 51.4 6.9 32.5
Indicators
Chest whistling due to physical movements Chest whistling while not doing physical movements Chest whistling due to colds Chest whistling Reasons of chest whistling
n=500 Frequency (%)
30
6.0
24
4.8
194 185
38.9 36.6
24
Yes No Frequency of chest whistling 1-3 4-12 more than 13 Shortness of breath in the 12 months
Cases diagnosed with asthma Cases taken medication for asthma in the last 12 months
Cases diagnosed with bronchitis Yes No
Dry cough not associated with any acute respiratory infection in the last 12 months Cases combined with itchy eyes Itchy rash Eczema
Snoring Yes Every night yes Tonsillectomy Yes
Morbidity of mothers Bronchitis Asthma
167 23
87.9 12.1
125 21 23
74.8 12.5 12.7
9
5.2
7
1.4
7
100
95 405
19 81
127
25.3
21 37 47
5.9 7.4 9.4
158
31.5
27
17.0
5
1
4
0.8
Smoking Dust Colds & coughing Frequency of wake up No Once in a week Twice or more than twice in a week Cases diagnosed with asthma in the last 12 months January October November December Period when cases were diagnosed with bronchitis January to February October December Problem of runny nose when he/she had no colds or flu Month that cases were revealed January October November December How many times in a week 1-2 3-4 Morbidity of siblings Bronchitis Asthma Eczema Hayfever Morbidity of fathers Bronchitis
44 25 148
26.4 14.9 88.6
87
52.1
68
40.7
12
7.2
7 2 1 2 2
100 28.5 14.5 28.5 28.5
16
16.8
83
83.2
162
32.3
32 17 40 51
19.8 10.5 24.7 31.4
82 49
62.5 37.5
7 13 175
1.4 2.6 35.0
-
25
Eczema Hayfever Death of child under 5 years old 0-1 2-3
16 155
3.2 31.0
20 16 4
4.0 80.0 20.0
Asthma Eczema Hayfever Cause of death Pneumonia Brain trauma Meningitis Do now know
6 11 133
1.2 2.2 26.6
8 2 7
40.0 15.0 10.0 35.0
The results showed that most of the children who were surveyed had respiratory symptoms.
Housing and Domestic Characteristics
In terms of the number of people in the household, 49.8% of the households surveyed had 4-5 members and 25.2% had 6-7 members. Of those households that were included in the study, 36.7% had 1 child less than 12 years old, 37.7% had 2 children, 19.8% had 3 children and 94.2% had 1-3 children (Table 3). In terms of the material of the children's bedroom floor, 59.2% mainly used carpet, 47.0% used linoleum and 56.4% used wood. Of those 500 households involved in the study, 33.4% had central heating while 46.4% mainly used coal and 56.4% used wood for heating. Those with central heating were warm for 24 hours a day while 15.6% made a fire 1-2 times per day and 40.8% made a fire 3-4 times a day. In terms of the frequency of air ventilation, 62.0% of the households opened window every day while 15.6% opened once in a week and 22.4% seldom opened in a month or never opened a window in the winter season. For the summer season, 97.0% opened a window every day while 3.0% never opened the windows (Table 3).
Table 3. Housing and Domestic Characteristics Indicators HOUSING CONDITION Years since built dwelling: 1-10 11-20 21-30 31-40
N=500 Frequency (%)
242 160 58 33
Indicators
Years lived in that dwelling: 1-10 11-20 21-30
n=500 Frequency (%)
188 104 26
37.6 20.8 5.2 26
41-50 more than 50 the number of family members: 2-3 4-5 6-7 8-9 10-11 Air quality by residents’ evaluation: Very good Good Average Bad
Frequency of household heating: 24 hours 1-2 times 3-4 times 5-6 times more than 7 times Frequency of air ventilation in winter season: Every day Once in a week Once in a month Rarely Never Using fan for smoke and steam while cooking and bathing: Usually Sometimes Never used Do not have Drying washed clothes at home: Yes No Pets Yes No
6 1
78 249 126 27 20
31-50
15.6 49.8 25.2 5.4 4.0
72 362 66
14.4 72.4 13.2
167 78 204 14 37
33.4 15.6 40.8 2.8 7.4
310/485 78/5 7/2 50/2 55/6
8/2 3/4 15/5 47/89
344 156 140 160
the number of children under 12: 1 2 3 4-5 Type of heating used in winter season: Central heating Coal burning Wood burning Air conditioner Electric heater Other Fuel used for cooking: Electricity Wood Coal Gas and other
Fungi Yes 62.0/97.0 No 15.6/1.0 1.4/0.4 10.0/0.1 11/1.2 Moisture at home: Yes No 1.6/0.4 0.6/0.8 3.0/1.0 94.8/97.8 Household window frosty: 68.8 Yes 31.2 No Street movement 28.0 around households 97.0 Very much Much Less
15
19.6
183 188 99 29
36.7 37.7 19.8 5.8
167 232 282 2 10 9
33.4 46.4 56.4 0.4 2.0 1.8
295 263 253 6
59.0 52.6 50.6 1.2
15 485
3.0 97.0
106 394
21.2 78.8
148 352
29.6 70.4
136 214 150
27.2 42.8 30.0
27
In terms of the frequency of weekly usage of stoves, 70.2% of the total households or most of them used the stove 1-14 times per week and 54.6% of the households spend 11.5 hours on average for cooking each time. Of the studied households, about 98% did not use a fan for eliminating smoke or steam during cooking and bathing. Of the households, 59.0% used electricity, 52.6% used wood and 50.6% used coal for cooking. Also, 68.8% dried clothes at home. This is probably linked to 21.2% of the households responding that their homes became moist, 29.6% of the households responding that windows became frosty, and 3.0% observing that they had fungi. It can be concluded that unsatisfactory usage of fans and drying clothes at home could affect indoor air quality. Of those who were involved in the study, 70.0% were living in the area of high traffic while 30% were living in areas with less traffic.
Smoking In the studied households, 59.5% (296) had smokers. Of those households that had smokers, 82.4% had 1 smoker family member while 15.2% had 2 members and 2.4% had 3 members. According to the frequency of smoking most of the smokers or 86.1% smoked every day. Also of the households which had smokers, 96.4% of visitors who came to the home were smokers and of those 73.6 % (368) smoked in the studied households (Table 4). Table 4. Smoking Indicators SMOKING STATUS Smokers in the studied households: Yes No Frequency of smoking: Every day Sometimes in a week Sometimes in a month Rarely
n=500 Frequency (%)
296 204
59.2 40.8
255
86.1
22
7.4
1 18
0.3 6.1
Indicators
How many if there are smokers: 1 2 3 Visitors who smoke: Every day Once in a week Sometimes in a month Rarely Never
n=500 Frequency (%)
244 45 7
82.4 15.2 2.4
65
13.0
94
18.8
132 191 18
26.4 38.2 3.6
28
It showed that smoking is common among the studied household members. In other words, 59.2% of households involved in the study are affected by direct and indirect tobacco smoke.
SUMMARY
(1)
Of the 500 children who were involved in the cross sectional study, 19% had
bronchitis and 1.4% had asthma (Table 5).
Table 5. Prevalence of asthma and bronchitis by age Age
(2)
Asthma
Bronchitis
Frequency
%
Frequency
%
2
0
0
10
2.0
3
1
0.2
7
1.4
4
2
0.4
20
4.0
5
1
0.2
12
2.4
6
0
0
14
2.8
7
1
0.2
17
3.4
8
2
0.4
15
3
Total
7
1.4
95
19
Among the 500 children, 77.8% had respiratory symptoms and morning cough and
phlegm were common (Table 6).
Table 6. Prevalence of respiratory symptoms by districts
Districts
Respiratory symptoms
Total percentage %
Sukhbaatar
Actual number 250
Chest tightness 6.8
Morning cough 35.6
Shortness of breath 4.4
Morning phlegm 21.2
Bayangol
250
7.6
44.4
6.4
6.4
87.6
Total
500
7.2
40.0
5.4
5.4
77.8
68.0
29
(3)
When we studied bronchitis, emphysema and allergic diseases, bronchitis was very
common and most of the children in the Gher areas had bronchitis (Table 7).
Table 7. Prevalence of bronchitis and asthma by type of dwelling
Houses uses fuels Diseases
Apartment Frequency
Gher % Frequency
Houses
Total
%
Frequency
%
Frequency
%
Bronchitis
32
33.7
28
29.5
35
36.8
63
66.3
Asthma
1
14.3
3
42.9
3
42.9
6
85.7
(4)
The frequency of respiratory symptoms was higher in children who lived in Ghers
and houses than those who lived in apartments (Table 8).
Table 8. Respiratory symptoms by type of dwelling
Symptoms
Apartment
Gher and houses
Total
Percentage
Percentage
Percentage
Chest tightness
1.4
5.8
7.2
Morning cough
14.4
25.6
40.0
Shortness of breath
1.0
4.4
5.4
Morning phlegm
9.0
16.2
25.2
3.2 CASE CONTROL STUDY
Sample Demographics
A total of one hundred fifty children aged between 0 and 5 participated in the study and 58% (87) were males and 42% (63) were females. Of them there were 71 cases and 78 controls. Random sampling was used in the case control study and cases of bronchitis were predominant among the children aged between 2 and 5.
30
Of the respondents who were interviewed about children, 72% (108) were mothers of the children, 6 % (9) were fathers, 7.3% (11) siblings and 18.7% (28) were other members of families. In terms of the educational level of parents of children who were involved in the study, 27.7% had a university education, 15.3% had vocational education, 43.8% had finished high school, 12.5% had finished secondary school and 0.75 had primary education or no education (Table 9). Table 9. Sample demographics Indicators
Cases n = 71 (%)
Controls n = 78 (%)
Frequency
%
42 (59.2) 29 (40.8)
45 (57.7) 33 (42.3)
87 62
58.0 42.0
14 (19.7) 23 (32.4) 14 (19.7) 9 (12.7) 2 (2.8) 7 (9.9) 2 (2.8)
8 (10.5) 18 (23.7) 13 (17.1) 17 (22.4) 15 (19.7) 1 (1.3) 4 (5.3)
22 41 27 26 18 8 6
14.9 27.7 18.2 17.6 12.2 5.4 4.0
6 (8.4) 31 (43.7) 11 (15.5) 23 (32.4)
11 (14.3) 34 (44.1) 15 (19.5) 17 (22.1)
18 66 26 40
12.1 44.0 17.3 26.8
9 (14.3 ) 27 (42.8) 6 (9.5) 21 (33.3)
10 (14.7) 30 (44.1) 11 (16.2) 17 (25.0)
19 57 17 38
14.5 43.5 13.0 29.0
Total n=149
Sex: Male Female Age of child: 2 3 4 5 6 7 8 Level of education of mother: Primary or no education Secondary Vocational University Level of education of father: Primary or no education Secondary Vocational University
Child Health
The results of the questionnaire on child health showed that of the children who were involved in the study, 46.0% had morning cough, 29.3% had morning phlegm, 21.3% had chest tightness and 11.5% had shortness of breath (Figure 3).
31
Figure 3. Respiratory symptoms 46
50 40
29.2
30 21.3 20 11.5 10 0 Chest tightness
Morning cough
Shortness of breath
Morning phlegm
It was observed that 44 (29.3%) had wheezy chest in the previous 1 month after physical movements. Of the 31.1% children who were diagnosed with bronchitis by family doctors 8.1% had mild, 23.0% had milder, 51.4% had moderate and 17.6% had severe bronchitis (Figure 4). Figure 4
Expectations (prognosis) of bronchitis 17.6
Severe
51.3
Moderate
31.1
Mild
0
10
20
30
40
50
60
Cases of bronchitis were predominant in November, December and January. During the cold season, there were emissions from power stations, small stations and family fires. The poor indoor and outdoor air quality results in people having more respiratory symptoms (Table 10).
32
Table 10. Child Health
Indicators Respiratory symptoms in the previous 1 month: Chest tightness Morning cough Shortness of breath Morning phlegm Chest wheezy Expectations (prognosis) of bronchitis: Mild Milder Moderate Severe Month when diagnosed bronchitis: January February October November December Snoring: Yes Snore every day: Yes Frequency of snoring per week: 1-2 times 3-4 times Morbidity of siblings: Bronchitis Asthma Tonsillitis Allergy Morbidity of mothers: Bronchitis Asthma Tonsillitis Allergy Morbidity of fathers: Bronchitis Asthma Tonsillitis Allergy *P
