Browsing by Author "Ahmed, S."
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Item Open Access Automotive related exposure to particulate air pollution in developing countries cities(Pakistan Agricultural Scientists Forum, 2015-06-30) Nasir, Zaheer A.; Colbeck, Ian; Ali, Z.; Ahmed, S.Poor urban air quality in developing countriesis a growing public health challenge due to rises in population, industries, urbanization and vehiclesalong with insufficient air quality management. Among the range of air pollutants exposure to particulate matter (PM) is of greatest concern due to its association with chronic obstructive pulmonary diseases. The present study reports traffic related exposure to PM by the roads in Lahore, Pakistan. The measurements of mass and number of PM were carried out by GRIMM analysers (Model 1.108 and Model 1.101) and condensation particle counter (TSI 3781). The heavy metals concentration in PM was determined by Graphite Furnace Atomic Absorption Spectrophotometer (Unicam atomic absorption, Cambridge, UK). The mean hourly average concentration of PM10, PM2.5, PM1 and PM10 (-) (2.5) at the road siteswas higher during weekdays(305 mu g/m(3), 84 mu g/m(3), 61 mu g/m(3) and 222 mu g/m(3), respectively) in comparison to the weekend (136 mu g/m3, 60 mu g/m3, 40 mu g/m3 and 76 mu g/m(3), respectively). At the background site the levels in the same size fractions were 206 mu g/m(3), 63 mu g/m(3), 31 mu g/m(3), and 143 mu g/m(3), respectively. Likewise, the number concentration of ultrafine particles was considerably higher at road sites (417,003 #/cm(3)) than the background(97,300 #/cm(3)). The concentration of heavy metals in PM decreased in the following order: Si, Al, Zn, Mn, Cu, Ni, Cd, Pb. Overall, the concentration of PM10, PM2.5 and toxic metals (Mn, Cd, Ni) was substantially higher than guidelines by the WHO. Furthermore, relatively higher levels of the fine fraction (PM2.5 and PM1) in the background reflect their higher residence time and resultant increased risk of exposure to the wider public beyond that of the vicinity to automotive sources. Everyday commuters, mostly on two and three wheelers as well asthe residential population in urban areas are at an enhanced risk of exposure to high levels of particulate pollution.Item Open Access Heavy metal composition of particulate matter in rural and urban residential built environments in Pakistan(Pakistan Agricultural Scientists Forum, 2015-06-30) Nasir, Zaheer A.; Colbeck, I.; Ali, Z.; Ahmed, S.Heavy metals in outdoor and indoor airborne particulate matter (PM) and dust in different residential built environmentsat two rural and one urban site in Pakistan were analysed. An eight stage non-viable impactor (Thermo Fisher Scientific Inc., USA) loaded with EMP 2000 glass microfiber filter papers (Whatman, England) was used to collect airborne PM.The indoordust samples (settled dust) were collected from different indoor surfaces (floor, cupboards) in living rooms and kitchens from houses at rural sites. The outdoor samples were collected from courtyards of the houses.At the urban site dust samples were also collected by the roads at 27 different locations around Lahoreand at a background site (University of Veterinary and Animal Sciences).Additionally, samples of dung cake, used as solid fuel, at one of the rural sites were taken.Heavy metals (Si, Al, Zn, Mn, Cu, Ni, Cd, Pb, Co and As) were determined by Graphite Furnace Atomic Absorption Spectrophotometer. At rural site I, in general, the concentrations of metals were higher outdoors than indoors, except for slightly higher indoor levels of Cu (0.85.g/m3 indoor: 0.56 outdoor.g/m3 ), Si (3.31.g/m3 indoor: 3.17 outdoor.g/m3 ) and Pb(11.99 ng/m3 indoor: 9.32 outdoor ng/m3 ). At the rural site II the mean concentration were higher outdoors than indoors, excluding Ni which was considerably higher indoors (55.68 ng/m3 ) than outdoors (31.91 ng/m3 ).At the urban site,outdoors, Si had the highest concentration (3.46 .g/m3 ) followed by Al, Zn, Mn, Cu, Ni, Cd, Pb and Co. Similarly, the indoor levels had a maximum contribution from Si (12.30 .g/m3 ) followed by Al, Mn, Zn, Cu, Cd, As, Pb, Ni and Co.With reference to dust at rural site I the top five metals outdoors were Si (708 mg/kg), Al, Cu, Zn and Pb (52 mg/kg) while, indoors Al was highest (281 mg/kg), followed by Si, Cu, Zn and Pb (57 mg/kg). At rural site II, both outdoors and indoors, Al (274 mg/kg – outdoor: 266 mg/kg - indoor), Si, Zn, Cu and Pb (61 mg/kg – outdoor: 80 mg/kg - indoor) were the five most abundant metals.The main five metals in decreasing order of their concentration in the road dust around Lahore were Si (686 mg/kg), Al, Cu, Zn and Pb (81 mg/kg). On the other hand, the dust samples from the background site showed Si (345 mg/kg) > Al >Pb> Cu > Zn (73 mg/kg). The airborne metal concentration of Pb was within the guideline value of WHO (0.5 .g/m3 ) but the levels of Mn, Cd and Ni were higher at all sites than the guidelines proposed by European Commission and WHO highlighting the risk of exposure to toxic metals in non-occupational environments.Item Open Access Spatial and temporal variations in indoor air quality in Lahore, Pakistan(Springer, 2018-05-21) Colbeck, Ian; Sidra, S.; Ali, Z.; Ahmed, S.; Nasir, Zaheer A.Indoor air pollution is a significant economic burden in Pakistan with an annual cost of 1% of gross domestic product. Moreover, according to the World Health Organization 81% of the population use solid fuels with 70,700 deaths annually attributable to its use. Despite this situation, indoor air pollution remains to be recognized as a hazard at policy level in Pakistan and there are no standards set for permissible levels of indoor pollutants. The current study was designed to monitor the indoor air quality in residential houses (n = 30) in Lahore, Pakistan. PM2.5 and bioaerosols were monitored simultaneously in the kitchens and living rooms. Activity diaries were kept during the measurement periods. It was observed that cooking, cleaning and smoking were the principal indoor sources while infiltration from outdoors, particularly in the semi-urban and industrial areas, also made significant contributions. Maximum and minimum air change rate per hour was determined for each microenvironment to observe the influence of ventilation on indoor air quality. Lahore has a low-latitude semi-arid hot climate, and a significant impact of season was observed upon bacterial and fungal levels. It was also observed that the PM2.5 levels rose during the colder months and decreased significantly during the summer season. Low ventilation rates during the winter season as well as meteorological factors resulted in elevated PM levels.