Abstract
The study was primarily initiated to explore possibility of chemical transformation of NOx to nitrates and get adsorbed onto the fine particle surfaces based on secondary data from various sources. This required manipulations of secondary data to find correlations between PM, PM-nitrates and NOx. Data were downloaded from EPA’s website (Environmental Protection Agency, USA; www.epa.gov), which include 24 hours PM10, PM2.5, PM1 and NOx concentrations. The corresponding PM-nitrate concentrations were obtained by manipulations made on various graphs of ambient particulate composition. Subsequently, coefficients of correlation among various parameters were calculated. It was observed that stronger correlations are obtained between PM-nitrates and NOx as size of particle is decreased. A similar trend was observed during an air quality monitoring exercise in Delhi. The ambient interactions between PM and NOx further imply that ambient NOx values obtained during air pollution monitoring are superficial and, thus, there is a need to revise the existing PM-NOx standards. From the health point of view, the synergistic interactions between PM and NOx have more deleterious effect on human health than NOx alone.