AIRBORNE MICROFLORA AND PARTICULATE MATTER IN RESIDENTIAL. HOUSES IN LAHORE, PAKISTAN. Sidra Safdar3, Zulfiqar Ali3,Ian Colbeck1 and ...
AIRBORNE MICROFLORA AND PARTICULATE MATTER IN RESIDENTIAL HOUSES IN LAHORE, PAKISTAN Sidra Safdar3, Zulfiqar Ali3,Ian Colbeck1 and Zaheer A.Nasir2 1School
of Biological Sciences, University of Essex, Colchester, Essex, CO4 3SQ, UK 2Department of Civil, Environmental and Geomatic Engineering, University College London, WC1E 6BT, UK 3Department of Zoology, University of the Punjab, Lahore, Pakistan
Introduction
Table 1 Summary of housing types
small (5575 CFU/m3)
Air-borne micro-organisms are ubiquitous in the environment and can account for up to 50% all aerosol particles indoors. Their sources depend generally on the number of the occupants, their activities, building structure and material, furnishings, and the outside air entering the building. Few studies have been conducted in Pakistan regarding indoor air quality and fewer still on bioaerosols.
medium (3865 CFU/m3)
large (5776 CFU/m3)
Lahore (31.55°N and 74.34°E) is the second biggest city of Pakistan and the provincial capital of Punjab. It is one of the most densely populated cities of the world with an estimated population of 10,000,000.
Figure 6. Variation in fungi concentration in kitchens for different size houses (average)
Objectives The current study was undertaken to monitor the concentration of bioaerosols in different residential settings within Lahore and to identify the predominant bacteria and fungi in the air. NG (natural gas); LPG (liquefied petroleum gas); Ti (tiled); Ta (tarred), Ce (cemented); Un (unpaved)
Methodology
Figure 7. Seasonal variation (k = kitchen, lv = living room
Thirty houses were selected and sampling was carried out from January 2012 until March 2013. Houses were classified in terms of their size. The gravitational method was applied to collect bioaerosols from the kitchens and living rooms. Agar coated petri plates were exposed face upwards for twenty minutes at each location. The medium used for bacterial sampling was Trypticase Soy Agar (TSA) while Malt Extrose Agar (MEA) was used for fungal sampling. The exposed petri plates were incubated at 37oC for three days. The number of colonies was then counted and the species identified. The number of colony forming units per cubic meter (CFU/m3) was determined by Omelyansky’s formula.
Table 2. Correlations between bacteria and fungi concentrations with temperature, relative humidity and number of occupants CATEGORY A
temp & CFU/m3 (bacteria) temp & CFU/m3 (fungi) humidity & CFU/m3 (bacteria) humidity & CFU/m3 (fungi) occupants & CFU/m3 (bacteria) occupants & CFU/m3 (fungi) CFU/m3 (bacteria) CFU/m3 (fungi)
CATEGORY B
CATEGORY C
KITCHEN
LIVING ROOM
KITCHEN
LIVING ROOM
KITCHEN
LIVING ROOM
0.77
0.66
0.73
0.58
0.28
0.54
0.40
0.38
0.26
0.34
-0.12
-0.01
0.04
0.04
0.10
0.19
0.19
-0.44
-0.16
-0.01
0.26
0.35
-0.05
0.20
0.53
0.48
-0.10
-0.01
-0.02
-0.009
0.05
0.05
0.003
-0.15
-0.42
-0.62
0.92
0.79
0.53
0.87
0.63
0.81
Figure 2. Example floor plans
Results and Discussion
Figure 3. Percentage of bacterial species observed in the kitchens and living rooms of different sized houses Figure 1. Location of sampling sites A: small: < 126.5 m2 B: medium: > 126.5 m2 to 253 m2 C: Large: > 253 m2
Figure 4. Percentage of fungal species observed in the kitchens and living rooms of different sized houses small (6299 CFU/m3)
medium (3118 CFU/m3)
large (5194 CFU/m3)
Figure 5. Variation in bacteria concentrations in the living rooms for different size houses (average)
• A total of 7 bacterial species and 11 fungal species were identified. • Predominant bacterial species were Staphylococcus spp. (37% in kitchens & 35% in living rooms) and Micrococcus spp. (28% & 30% respectively). Aspergillus fumigatus (25% in kitchens & 23% in living rooms) and Alternaria alternata (19% & 30% respectively) were the most abundant fungal species. • Bioaerosols concentrations did not have any strong association with the activities of the surrounding environment • Similarity between the microflora of the two micro-environments may be due to outdoor sources.
