City-wide sweeping a source for respirable particulate matter in the atmosphere

Abstract

Most of the cities located in Northern India are afflicted with the presence of unusually high concentration of PM 10 in the ambient environment posing a serious risk to human health. To understand the reasons underlying the persistence of the high levels of PM 10 in the Delhi region, a novel experiment was designed by appropriating a well-known tracer-source—Diwali fireworks—emitting a large amount of particulate matter (PM) in the atmosphere. Sequential eight hourly PM 10 samples were collected and analyzed for the elemental signatures associated with the tracer and other sources. Principal component analysis was used to resolve the sources; their respective mass contribution to PM 10 load, in time sequence, was estimated using absolute principal component score method. The results suggest that the well-established practice of city-wide street-cleaning, resuspends the surface deposited PM 10 back to the atmosphere. We suspect that this practice resuspends about 25% of the sedimented PM 10 back into the atmosphere.