Temporal distribution of fine particulates (PM2.5, PM10), potentially toxic metals, PAHs and Metal-bound carcinogenic risk in the population of Lucknow City, India

Ubiquitous fine particulates can readily be bound to toxic metals and polycyclic aromatic hydrocarbons and are considered to be a great threat to human health. The purpose of this study was to assess the magnitude of air pollution risks to public health by determining four crucial parameters- inhalable particulates, metals in particulates and PAHs which are associated with PM10 in the air environment of Lucknow, India during 200709. The values of PM10 and PM2.5 ranged between 102.3240.5 and 28.0196.9g/m3 whilst the average PM10 was 1.7times and PM2.5 was 1.5times higher than their respective NAAQS of 100 and 60g/m3 respectively. The estimated relative death rate and hospital admissions for each increase in the PM10 levels of 10g/m3 ranged from 1.58% and from 3.98.0% (as per APHEA2 1990) respectively in persons > 65 yrs. Among the locations; AQS-1, AQS-2, and AQS-3 (with diversified activities and heavy traffic) recorded higher concentrations of both the particulate fractions than the AQS-4 (residential area with low traffic). The average concentrations of Fe, Pb, Ni, Cu, Cr, Cd in PM10 were 219.4, 40.6, 35.1, 27.3, 22.2 and 16.2ng/m3 and that in PM2.5 were 54.3, 33.9, 38.5, 29.4, 8.4, and 1.17ng/m3 respectively. Regression analysis revealed that correlation of metals with PM2.5 was stronger than PM10. The ratio of metals adsorbed on surface of particles (PM2.5:PM10) reveals that PM2.5 has more affinity for Ni, Cu and Pb and PM10 for Cd, Fe and Cr. Health risk due to carcinogenic metals bound to respirable particulates was predicted by estimating excess cancer risk (ECR). The highest ECR value was estimated for Cr, 266.70 x 106, which was associated with PM10 and 100.92 x 106 which was associated with PM2.5, whereas lead has the lowest ECR value. Amongst PAHs, benzo(a)pyrene (51.96 +/- 19.71ng/m3) was maximum in PM10 samples. Maximum concentrations of PM10, PM2.5, metals and PAHs were detected during winter, and the lowest was during monsoon. The higher prevalence of diseases among the population may be due to high concentration of particulates coated with toxic metals and PAHs present in air environment.