Residential biomass burning emissions over Northwestern Himalayan region of India: Chemical characterization and budget estimation

Abstract

In the present study, we have determined the emission factors (EF) and estimated the emission of particulate matter (PM), organic carbon (OC), elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), water soluble inorganic constituents (WSIC) and trace gases such as SO2, NO and NO2 from the combustion of biomass fuels (FW: fuel wood and DC: dung cake) used in rural sectors for cooking over Himachal Pradesh (HP), representing the Northwestern Himalayan region of India. The average EFs of PM estimated from FW and DC were 3.44 ± 2.38 and 11.43 ± 1.13 g kg-1, respectively. OC and EC emission ranged from 0.106 to 3.55 g kg-1 and 0.07 to 0.90 g kg-1, respectively for variety of biomass fuels. Total emission of PAHs from DC (44.37 mg kg-1) and FW (43.25 mg kg-1) noted in this study was almost similar. Similarly, the average EFs of NOx from FW and DC were 0.59 ± 0.49 g kg-1 and 0.34 ± 0.18 g kg-1, respectively. FWs have comparatively higher SO2 emission (average: 0.43 ± 0.38 g kg-1) than from DC (average: 0.23 ± 0.15 g kg-1). Among anionic inorganic constituents emitted from FW, maximum EF was noted for Cl-(0.30 ± 0.26 g kg-1). Similarly for cations, highest EF was noted of K+ (0.20 ± 0.09 g kg-1). Ca2+ and Na+ were the major cationic species identified in plumes of DC burning. Utilizing total annual consumption of biomass fuels and EFs of particulates and trace gases determined in the present study over HP and in the past study (Saud et al., 2011, 2012) over Uttarakhand, budget estimates of PM, OC, EC, TC, PAHs, SO2 and NOx have been determined over the Northwestern Himalayan region. Total annual emission estimated over Northwestern Himalayan region are as: PM (18.32 ± 9.53 Gg), OC (4.38 ± 2.31 Gg), EC (1.39 ± 0.55 Gg) and trace gases (SO2: 1.47 ± 1.0 Gg; NOx: 1.77 ± 1.31 Gg).