P. R. Sinha

The impact assessment of Diwali fireworks emissions on the air quality of a tropical urban site, Hyderabad, India, during three consecutive years

Diwali is one of the largest festivals for Hindu religion which falls in the period October–November every year. During the festival days, extensive burning of firecrackers takes place, especially in the evening hours, constituting a significant source of aerosols, black carbon (BC), organics, and trace gases. The widespread use of sparklers was found to be associated with short-term air quality degradation events. The present study focuses on the influence of Diwali fireworks emissions on surface ozone (O3), nitrogen oxides (NOx), and BC aerosol concentration over the tropical urban region of Hyderabad, India during three consecutive years (2009–2011). The trace gases are analyzed for pre-Diwali, Diwali, and post-Diwali days in order to reveal the festivity’s contribution to the ambient air quality over the city. A twofold to threefold increase is observed in O3, NOx, and BC concentrations during the festival period compared to control days for 2009–2011, which is mainly attributed to firecrackers burning. The high correlation coefficient (~0.74) between NOx and SO2 concentrations and higher SO2/NOx (S/N) index suggested air quality degradation due to firecrackers burning. Furthermore, the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation-derived aerosol subtyping map also confirmed the presence of smoke aerosols emitted from firecrackers burning over the region. Nevertheless, the concentration level of pollutants exhibited substantial decline over the region during the years 2010 and 2011 compared to 2009 ascribed to various awareness campaigns and increased cost of firecrackers.

Aerosol Characteristics over Bay of Bengal During W-ICARB Cruise Campaign

Detailed observations of aerosol optical and physical properties were carried out to study variability at the sea surface, along vertical profiles and total column during the Winter-Integrated Campaign on Aerosols, Gases and Radiation Budget (W-ICARB) from 27 December 2008 to 30 January 2009 in the Bay of Bengal (BoB). The results show large heterogeneity in aerosol load and characteristics; dominance of anthropogenic aerosols over the northern BoB, along the eastern Indian coast and in Far East BoB region and higher fraction of coarse-mode aerosols over the southern parts of BoB. The aerosols over the area are highly influenced by the Indian continental outflow and the biomass burning in the Southeast Asia. On the other hand, the larger fraction of coarse-mode aerosols over the southern BoB is closely associated with intense sea-surface winds producing coarse-mode sea-salt aerosols. The vertical profiles of aerosols obtained via CALIPSO data also exhibit considerable vertical heterogeneities.