Health Risk Assessment of Different Sources of Metals in PM₁₀ and PM_2.5 in the Largest City in Northeast India

Abstract

Northeast India, home to a population of 46 million, has the highest infant mortality rate in the country. Some of these infant mortalities might be attributed to exposure to toxic air pollutants, especially heavy metals. To explore this, seasonal changes in the source contributions of these metals were studied, using a positive matrix factorization model, in a residential area in the largest city in the region. The mean particulate matter with aerodynamic diameter ≤ 10 and ≤ 2.5 µm (PM10 and PM2.5) concentrations were found to be 90 and 69 μg/m3, respectively. Particles from biomass burning, coal mining, Dust emissions types 1 and 2, and industry and vehicular emissions were found in both PM10 and PM2.5. A comparison between the source contributions to PM10 and PM2.5 during clean and pollution days revealed that the highest concentrations were not only due to stagnant weather conditions, but also to changes in emissions from the different sources. Further analysis was carried to estimate the overall health risk associated with each source and the carcinogenic risk from the metals. The results revealed that more emphasis should be given to the health effects associated with each source when designing control strategies, rather than just concentrating on the source that contributes the maximum mass.