%0 Journal Article
%T Interannual and Intraseasonal Variability in Fine Mode Particles over Delhi: Influence of Meteorology
%A S. Tiwari
%A D. S. Bisht
%A A. K. Srivastava
%A G. P. Shivashankara
%A R. Kumar
%J Advances in Meteorology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/740453
%X Fine mode particles (i.e., PM2.5) were collected at Delhi, India, for three consecutive years from January 2007 to December 2009 and were statistically analyzed. Daily mean mass concentration of PM2.5 was found to be 108.81 ¡À 75.5£¿¦Ìg£¿m£¿3 ranged from 12 to 367.9£¿¦Ìg£¿m£¿3, which is substantially higher than the Indian National Ambient Air Quality Standards (NAAQS). Among the measurements, ~69% of PM2.5 samples exceeded 24£¿h Indian NAAQS of PM2.5 level (£¿¦Ìg£¿m£¿3); however, ~85% samples exceeded its annual level (40£¿¦Ìg£¿m£¿3). Approximately 30% of PM2.5 mass was in the range of 40¨C80£¿¦Ìg£¿m£¿3, indicating abundance of fine particles over Delhi. Intraseasonal variability of PM2.5 indicates highest mass concentration during postmonsoon (154.31 ¡À 81.62£¿¦Ìg£¿m£¿3), followed by winter (150.81 ¡À 74.65£¿¦Ìg£¿m£¿3), summer (70.86 ¡À 29.31£¿¦Ìg£¿m£¿3), and monsoon (45.06 ¡À 18.40£¿¦Ìg£¿m£¿3). In interannual variability, it was seen that in 2008, the fine mode particle was ~23% and ~36% higher as compared to 2007 and 2009, respectively. Significantly negative correlation was found between PM2.5 and temperature (£¿0.59) as well as wind speed (£¿0.38). Higher concentration of PM2.5 (173.8£¿¦Ìg£¿m£¿3) was observed during calm conditions whereas low concentration (79.18£¿¦Ìg£¿m£¿3) was observed when wind speed was >5£¿Km/hr. In winter, greater exposure risk is expected, as the pollutant often gets trapped in lower atmosphere due to stable atmospheric conditions. 1. Introduction Aerosols, suspended in the atmosphere, are distributed through turbulence and direct atmospheric transport of air masses. These aerosols interact with Earth¡¯s energy budget, directly as well as indirectly. As a direct effect, aerosols scatter, absorb, and reflect solar energy that enters and exits in the Earth¡¯s atmosphere, while as an indirect effect, they altered the size, shape, and location of clouds and affected the precipitation in lower atmosphere [1¨C4]. Apart from this, atmospheric aerosols, especially fine particles, have received much attention during the last two decades due to their potential adverse impacts on human health and agricultural production. Particulate matters with aerodynamic diameters less than 2.5£¿¦Ìm (i.e., PM2.5), called fine particles, have especially been found to be associated with increasing respiratory illness, carcinogens [5], asthma [6], and ultimately in increasing the number of premature deaths [7¨C9]. Many epidemic studies have linked airborne concentrations of PM2.5 and PM10 with a variety of health problems, including morbidity and mortality [10]. Due to industrial and population growth,
%U http://www.hindawi.com/journals/amete/2013/740453/