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Atmospheric heating caused by anthropogenically emitted carbonaceous aerosols contributes to one of the largest uncertainties in climate forcing over south Asia (SA). Past studies have identified the combustion of fossil fuels and residential biofuels as being the dominant emitter of light-absorbing black carbon aerosols over this region. Here, we measure emissions from open-air burning of funeral pyres, a deep-rooted and widely prevalent custom in SA, and find that large amounts (≈98% by mass) of light-absorbing organic carbon (OC) aerosols, optically defined as brown carbon (BrC), are emitted per kilogram of feedstock burned. The emitted OC contributes an average 40% to the smoke particulate matter absorption of the visible solar radiation. We calculate funeral pyres in SA contribute approximately 92 Gg of light-absorbing OC annually, which is equivalent to ≈10 and 23% of the carbonaceous aerosol mass from regional biofuels and fossil fuels, respectively. Our findings underscore the importance of accounting for cultural burning practices as aerosol sources in emission inventories and BrC aerosols in climate models, as well as the development of mitigation strategies.

Many households use solid fuels for cooking and heating purposes. There is currently a knowledge gap in our understanding of the variations in indoor air quality throughout the household as most of the studies focus on the areas in the close proximity of the cookstove. A low-cost wireless particulate matter (PM) sensor network was developed and deployed in households in Raipur, India to establish the spatio-temporal variation of PM concentrations. The data from multiple sensors were acquired in real-time with a wireless system. Data collected from the sensors agreed well (R =0.713) with the reference data collected from a commercially available instrument. Low spatial variability was observed within the kitchen due to its small size and poor ventilation - a common feature of most rural Indian kitchens. Due to insufficient ventilation from open doors and windows, high PM concentrations similar to those found in the kitchen were also found in the adjoining rooms. The same household showed significantly different post-extinguished cookstove PM concentration decay rates (0.26mg/m-min and 0.87mg/m-min) on different days, owing to varying natural air exchange rates (7.68m/min and 37.40m/min).

Worshipping activity is a customary practice related with many religions and cultures in various Asian countries, including India. Smoke from incense burning in religious and ritual places produces a large number of health-damaging and carcinogenic air pollutants include volatile organic compounds (VOCs) such as formaldehyde, benzene, 1,3 butadiene, styrene, etc. This study evaluates real-world VOCs emission conditions in contrast to other studies that examined emissions from specific types of incense or biomass material. Sampling was conducted at four different religious places in Raipur City, District Raipur, Chhattisgarh, India: (1) Hindu temples, (2) Muslim graveyards (holy shrines), (3) Buddhist temples, and (4) marriage ceremony. Concentrations of selected VOCs, respirable particulate matter (aerodynamic diameter, <5 μm), carbon dioxide, and carbon monoxide were sampled from the smoke plumes. Benzene has shown highest emission factor (EF) among selected volatile organic compounds in all places. All the selected religious and ritual venues have shown different pattern of VOC EFs compared to laboratory-based controlled chamber studies.

a b s t r a c tCombustion of solid biomass fuels is a major source of household energy in developing nations. Black (BC) and organic carbon (OC) aerosols are the major PM 2.5 (particulate matter with aerodynamic diameter smaller than 2.5 μm) pollutants co-emitted during burning of these fuels. While the optical nature of BC is well characterized, very little is known about the properties of light absorbing OC (LAOC). Here, we report the mass-based optical properties of LAOC emitted from the combustion of four commonly used solid biomass fuels-fuel-wood, agricultural residue, dung-cake, and mixed-in traditional Indian cookstoves. As part of a pilot field study conducted in central India, PM 2.5 samples were collected on Teflon filters and analyzed for their absorbance spectra in the 300-900 nm wavelengths at 1 nm resolution using a UV-Visible spectrophotometer equipped with an integrating sphere. The mean mass absorption cross-sections (MAC) of the emitted PM 2.5 and OC, at 550 nm, were 0.8 and 0.2 m 2 g À 1 , respectively, each with a factor of $ 2.3 uncertainty. The mean absorption Ångström exponent (AǺE) values for PM 2.5 were 3 7 1 between 350 and 550 nm, and 1.27 0.1 between 550 and 880 nm. In the 350-550 nm range, OC had an AǺE of 6.3 7 1.8. The emitted OC mass, which was on average 25 times of the BC mass, contributed over 50% of the aerosol absorbance at wavelengths smaller than 450 nm. The overall OC contribution to visible solar light (300-900 nm) absorption by the emitted particles was 26-45%. Our results highlight the need to comprehensively and accurately address: (i) the climatic impacts of light absorption by OC from cookstove emissions, and (ii) the uncertainties and biases associated with variability in biomass fuel types and combustion conditions, and filter-based measurement artifacts during determination of MAC values.

Owing to its unique nutritional and immunological characteristics, human milk is the most important food source for infants. Breast milk can, however, also be a pathway of maternal excretion of toxic elements. Selected toxic elements (As, Pb, Mn,a Hg and Cd) were determined in human breast milk and blood samples obtained from 120 subjects related to an integrated steel plant environment located in central India. Samples of breast milk and blood from subjects living outside the steel plant environment were also analyzed for comparative study. Higher levels of these toxic elements were found in blood samples as compared to breast milk samples. Plant workers showed the higher presence of these metals in their breast milk and blood samples compared to the residents of the area and the subjects living outside the industrial environment, respectively. Mn, Pb and Hg have shown a higher tendency to associate with blood and breast milk than As and Cd. The order of occurrence of these metals in blood and milk samples thus found is Mn > Pb > Hg > As > Cd.

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