Size-Segregated Characteristics of Carbonaceous Aerosols over the Northwestern Indo-Gangetic Plain: Year Round Temporal Behavior

Abstract

Size-segregated aerosol samples (PM <0.95 , PM 0.95-1.5 , PM 1.5-3.0 , PM 3.0-7.2 and PM >7.2 ) were collected over Patiala (30.33°N, 76.40°E; 250 m amsl), a semi-urban city located in northwestern Indo-Gangetic Plain (IGP) during October, 2012 to September, 2013. These samples were analyzed for carbonaceous aerosols (organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC)) to study their temporal variation, prevailing emission source (s) and secondary formation processes. Annual average of total suspended particulates (TSP) concentration, estimated by adding the aerosol concentrations in different size ranges, was found to be 199 ± 82 µg m -3 , varying from 88-387 µg m -3 with majority of particulate mass found in submicron size (PM <0.95 ). ), respectively over an annual cycle. Highest mass fraction of OC (> 75%) and WSOC (> 80%) was observed in submicron size, suggesting that OC mainly comes from combustion and/or secondary source (s). It has been observed that almost half of OC is secondary. On the other hand, climate forcing agent EC in PM <0.95 varied from 1.1 to 9.8 µg m -3 (4.8 ± 2.2 µg m -3 ). High mass ratios of OC/EC (~1.5-7.2) and WSOC/OC (~0.33-0.68) indicate the relative dominance of biomass burning emission over the study region. Total carbonaceous aerosols account for ~10-59% of submicron particulates mass (PM <0.95 ), indicating that fine particulates are enriched with carbonaceous species. These results have implications to regional climate model development and validation.

Chemical Characterization of Fine Atmospheric Particles of Water-Soluble Ions and Carbonaceous Species in a Tropical Urban Atmosphere over the Eastern Indo-Gangetic Plain

“…Studies conducted on carbonaceous aerosols over the last decade on different temporal scales (monthly/annual mean) in various regions of India reported OC to EC ratio in the range of 2-8.4 (Venkataraman et al, 2002;Rengarajan et al, 2007;Ram et al, 2008;Rastogi and Sarin, 2009;Ram et al, 2012;Tiwari et al, 2013;Safai et al, 2014;Panda et al, 2016;Singh et al, 2016). A ratio of 6-8 is reported over northwestern India (viz., Ahmedabad, Mount Abu) and northern India (viz., Allahabad, Hisar) whereas a ratio less than 3 (Mumbai) is detected over western India and eastern India (viz., Bhubaneswar).…”

Quantification of organic carbon from biomass versus non-biomass burning emissions to fine aerosol

“…1), which is located in the northwestern part of the IGP during October-2012 to September 2013. Study region experiences two distinct types of large scale agricultural-waste burning episodes i.e., paddy-residue burning during October-November and wheat-residue burning in the month of May (Singh et al, 2016a). Red dots in Fig.…”

“…1 (captured with Moderate Resolution Imaging Spectroradiometer (MODIS) onboard polar orbiting NASA's satellite during end of the October month) denote the fire counts, which indicates that high BB activities were present over the study region during that time. For complete description about the sampling site and prevailing emission sources, reference is made to our earlier publications (Rastogi et al, 2015;Singh et al, 2016a;Rastogi et al, 2016).…”

“…Based on replicate analyses of samples, the precision of measurements for water-soluble ionic species, OC and WSOC was found to be 5%, 8% and 4%, respectively. For complete description about the sizesegregated aerosol sampling and their chemical analysis reference is made to our earlier publications (Singh et al, 2016a and2016b). The average values 1.…”

Long-term measurements (2010–2014) of carbonaceous aerosol and carbon monoxide at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia

“…As a result, the total mass of aerosols increased by 480 % (local maximum), and the concentration of cloud condensation nuclei increased by 45 % (Joutsensaari et al, 2015). It is also projected that increased growth of the forest area resulting from the surface temperature increase will be accompanied by more frequent forest fires (Shvidenko et al, 2011), which are powerful sources of aerosol particles and greenhouse gases (Paris et al, 2009;Janhäll et al, 2010;Smolyakov et al, 2014). In addition, industrial production and a steady increase in oil and gas production in Siberia will further increase the concentrations of aerosols in the Siberian air basin.…”