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

Most of the cities located in Northern India are afflicted with the presence of unusually high concentration of PM10 in the ambient environment posing a serious risk to human health. To understand the reasons underlying the persistence of the high levels of PM10 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 PM10 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 PM10 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 PM10 back to the atmosphere. We suspect that this practice resuspends about 25% of the sedimented PM10 back into the atmosphere.