Household solid fuel burning emission characterization and activity levels in India.

Emission factors (EFs) of PM2.5, carbon fractions, major ionic (K+, Ca2+, NH4+, SO42-, NO3- and Cl-) and elemental (Al, Cr, Cu and Fe) species from combustion of commonly used household solid fuel were determined in 10 different states in India during cooking practices. The study involved sampling during actual household cooking involving use of a variety of fuels including coal balls (CB), fuel wood (FW), dung cakes (DC), crop residues (CR), mixed fuels (MF: dung cakes + fuel woods). Species-wise highest EFs (g·kg-1) were: 34.16 ±â€¯10.1 for PM2.5 (CB), 14.18 ±â€¯5.8 for OC (CB), 2.33 ±â€¯1.4 for EC (DC), 1.03 ±â€¯0.2 for K+ (CR), 2.21 ±â€¯0.6 NH4+ (DC), 0.61 ±â€¯0.2 for NO3- (CB), 0.59 ±â€¯0.1 for SO42- (CB), 0.69 ±â€¯0.1 for Cl- (CR) among the fuels. Higher OC EFs for CB could be attributed to higher moisture content (>13%) in coal-powder that is used to handmade coal balls. It is observed that, in general, OC3 and EC1 were the dominant thermally evolved carbon mass fractions. The study averaged MCE values were in the range 0.93-0.98, which could be attributed to higher variability in flaming and smoldering episodes during the combustion of selected fuels. Sum of ionic EFs for emissions from DC, CR and MF were found to be higher than those observed for FW and CB. The K+/EC and Cl-/EC (~1) ratios could be better indicators of CR fuels to differentiate it from FW, whereas NH4+/EC (~1) is suitable to indicate DC. Average annual emission estimates of PM2.5 (2.00 ±â€¯0.53 Tg·yr-1), OC (0.86 ±â€¯0.23 Tg·yr-1) and EC (0.11 ±â€¯0.02 Tg·yr-1) for tested fuels are evaluated to be contributing 27, 15 and 4% of total PM2.5, OC and EC, respectively, toward annual emission budget from different anthropogenic activities in India.

Temporal and spatial variations of PM2.5 organic and elemental carbon in Central India.

This study describes spatiotemporal patterns from October 2015 to September 2016 for PM2.5 mass and carbon measurements in rural (Kosmarra), urban (Raipur), and industrial (Bhilai) environments, in Chhattisgarh, Central India. Twenty-four-hour samples were acquired once every other week at the rural and industrial sites. Twelve-hour daytime and nighttime samples were acquired either a once a week or once every other week at the urban site. Each site was equipped with two portable, battery-powered, miniVol air samplers with PM2.5 inlets. Annual average PM2.5 mass concentrations were 71.8 ± 27 µg m-3 at the rural site, 133 ± 51 µg m-3 at the urban site, and 244.5 ± 63.3 µg m-3 at the industrial site, ~ 2-6 times higher than the Indian Annual National Ambient Air Quality Standard of 40 µg m-3. Average monthly nighttime PM2.5 and carbon concentrations at the urban site were consistently higher than those of daytime from November 2015 to April 2016, when temperatures were low. Annual average total carbon (TC = OC + EC) at the urban (46.8 ± 23.8 µg m-3) and industrial (98.0 ± 17.2 µg m-3) sites also exceeded the Indian PM2.5 NAAQS. TC accounted for 30-40% of PM2.5 mass. Annual average OC ranged from 17.8 ± 6.1 µg m-3 at the rural site to 64 ± 9.4 µg m-3 at the industrial site, with EC ranging from 4.51 ± 2.2 to 34.01 ± 7.8 µg m-3. The average OC/EC ratio at the industrial site (1.88) was 18% lower than that at the urban site and 52% lower than that at the rural site. OC was attributed to 43.0% of secondary organic carbon (SOC) at the rural site, twice that estimated for the urban and industrial sites. Mortality burden estimates for PM2.5 EC are 4416 and 6196 excess deaths at the urban and industrial sites, respectively, during 2015-2016.