Authors: S Tiwari A S Pipal Philip K Hopke D S Bisht A K Srivastava Shani Tiwari P N Saxena A H Khan S Pervez
Publish Date: 2015/03/11
Volume: 22, Issue: 14, Pages: 10744-10757
Abstract
Because of high emissions of anthropogenic as well as natural particles over the IndoGangetic Plains IGP it is important to study the characteristics of fine PM25 and inhalable particles PM10 including their morphology physical and chemical characteristics etc in Delhi during winter 2013 The mean mass concentrations of fine PM25 and inhalable PM10 continuous was 1176 ± 791 and 1910 ± 1276 μg m−3 respectively whereas the coarse mode PM10–25 particle PM mass was 7338 ± 285 μg m−3 During the same period offline gravimetric monitoring of PM25 was conducted for morphological analysis and its concentration was ~37 higher compared to the continuous measurement Carbonaceous PM such as organic carbon OC and elemental carbon EC were analyzed on the collected filters and their mean concentration was respectively 338 and 40 μg m−3 during the daytime while at night it was 412 and 101 μg m−3 respectively The average OC/EC ratio was 897 and 396 during the day and night respectively indicating the formation of secondary organic aerosols during daytime Effective carbon ratio was studied to see the effect of aerosols on climate and its mean value was 052 and 179 during night and day indicating the dominance of absorbing and scattering types of aerosols respectively into the atmosphere over the study region Elemental analysis of individual particles indicates that Si is the most abundant element ~37–90 followed by O oxide and Al Circularity and aspect ratio was studied which indicates that particles are not perfectly spherical and not elongated in any direction Trajectory analysis indicated that in the months of February and March air masses appear to be transported from the Middle Eastern part along with neighboring countries and over Thar Desert region while in January it was from the northeast direction which resulted in high concentrations of fine particlesThe authors gratefully thank the Director of IITM Pune for his encouragement and support for doing this study The corresponding author is thankful to the University Grant Commission F1171/201112/RGNFSCUTT502/SAIII/website New Delhi for financial support We also acknowledge the use of the HYSPLIT model of NOAAARL for back trajectory analysis The authors are very much thankful to the two anonymous reviewers for their valuable comments/suggestions which helped to improve the manuscript
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