Oxidative potential of atmospheric PM10 at five different sites of Ahmedabad, a big city in Western India

The current study presents the oxidative potential (OP) along with a wide range of chemical speciation of particulate matter with an aerodynamic diameter less than 10 mm (PM10) at five sites representing different environments in Ahmedabad, a big city in western India. On an average, PM10 concentrations were 116 +/- 36, 228 +/- 43, 133 +/- 29, 101 +/- 21, and 70 +/- 20 mu g m(-3); volume-normalized OP (OPV) were 2.51 +/- 0.71, 5.62 +/- 0.68, 2.69 +/- 0.76, 2.14 +/- 0.41, and 1.55 +/- 0.51 nmol DTT min(-1) m(-3); and massnormalized OP (OPM) were 22 +/- 3, 25 +/- 5, 21 +/- 6, 21 +/- 2, and 22 +/- 3 pmol DTT min(-1) mg(-1) over Bapunagar (backward residential area), Narol (industrial), Paldi (bus transport hub), Income Tax (huge running traffic) and Science City (posh residential area), respectively. Overall, OPV showed a significant linear correlation with PM10, whereas OPM showed near uniformity with increasing PM10. Although the OPM values were similar, the site-to-site variability in PM10 concentration reflects the corresponding health risks associated with PM10 exposure for the people living in these areas. Further, a noticeable temporal variation in OPM at Narol and Paldi suggests that species with diverse OPM contributed to PM10 on different days. A strong linear relationship between the ratio of OPV to the mass concentration of organic carbon (OPOC) and the ratio of m/z 43 signal to total water-soluble organic aerosols (WSOA) signals (f43) suggests that the fossil-fuel combustion derived WSOA have higher OP. Furthermore, the relationships of OP with water-soluble trace metals and brown carbon are also investigated and discussed in this paper. Nitrogenous organic compounds particularly emitted from the traffic-related sources in Paldi and Income Tax have higher OPOC than those emitted from other sources over Bapunagar, Narol, and Science City. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study in Ahmedabad, India, investigated the oxidative potential and chemical speciation of PM10 at different sites, revealing a significant linear correlation between OPV and PM10, while OPM showed near uniformity with increasing PM10. Site-specific variability in PM10 concentration reflects corresponding health risks, with notable temporal variations suggesting diverse species contributing to PM10. Relationships between OP and organic carbon, as well as other factors, were also explored.