This study highlights that the increasing urbanization and industrialization in Delhi are responsible for higher fluxes of atmospheric dust and its chemical constituents. Delhi has experienced a drastic change in land use and land cover area during the past two decades. Road lengths of the city have increased by 76% from 1985 to 2011. The number of mobile vehicles has reached 80,52,508 in 2014 from 24,32,295 in 1994. The industrial units in Delhi have increased by 39.54% in 2011 as compared to 1994 value. Atmospheric dust which is originated from soil in this region becomes carbon rich due to interaction of suspended soil with atmospheric pollutants. Emissions of carbonaceous aerosols from coal and petroleum combustions are mainly responsible for silica dominated soil dust transforming into carbon rich particulate matter. Such dust may play very important role in the atmosphere having significant influence on human health, global warming, climate change, radiative forcing, visibility, and cloud formation. It is expected that if the rate of development remains the same, green cover of the city invariably will be sized down in order to meet the demand of housing, transportation, industries, and so forth in proportion to the rising population.

Majority of India’s rural population depends on biomass burning for cooking and heating purposes on traditional cook stoves called Chullah which results into indoor air pollution. The sampling for this study was carried out in two villages of India viz. Budhwada, Madhya Pradesh (M.P.) and Baggi, Himachal Pradesh (H.P.). Both the regions are significantly different in terms of culture, traditions, topography and daily practices and hence this study helped in understanding the contrast between these regions. The concentrations of carbonaceous aerosols viz. OC (Organic Carbon) and EC (Elemental Carbon) were evaluated for different fuel use in four different houses of each village. Introducing the concept of soft approaches, the residents were asked to bring certain changes in their practices by cooking either with solid biomass or Liquefied Petroleum Gas (LPG) as fuel. The overall average concentration of OC was found to be higher for Budhwada (M.P.) at 124.34 ± 34.68 µg/m3 than at Baggi, (H.P.) with value 105.26 ± 35.63 µg/m3 whereas the reverse was true for the average concentration of EC with value 62.98 ± 20.75 µg/m3 at Baggi, (H.P.) and 55.51 ± 15.51 µg/m3 at Budhwada (M.P.). The average OC and EC concentrations from solid biomass fuel (dung cake) burning at Budhwada (M.P.) was respectively higher by 56.14% and 33.57% as compared to the LPG usage. Similarly, in Baggi (H.P.) village with LPG usage, a significant reduction was observed in OC and EC concentrations (76.69% and 70.10% respectively) when compared with fuelwood burning. House-wise and time-wise variations of carbonaceous aerosols at both the sites confirmed that their concentrations are lower in houses with greater ventilation and higher in cooking times (morning and evening). In Budhwada (M.P.), the concentrations of K+, Ca2+ and SO42- ions decreased significantly from dung cake to LPG use by 67.91%, 76.98% and 51.85% respectively. In Baggi (H.P.), K+ ion concentration was decreased by 63.4% from fuelwood to LPG use. A questionnaire survey conducted on the residents also corroborated the above findings where the residents agreed that LPG use has health benefits over solid biomass fuel usage but the challenges such as supply of LPG into rural interiors, financial feasibility, etc. were of serious concern. Also, changing the contemporary mindset of rural population is a challenging task.

Solid Biomass Fuel (SBF) burning is one of major reasons for the indoor air pollution and high disease burden in rural areas of India. This study has made an effort to find out the association of carbonaceous aerosol (CA) emissions with the socio-economic factors in the households of a rural village, Baggi in Himachal Pradesh, India. Also, the emissions of Organic Carbon (OC) and Elemental Carbon (EC) were evaluated for different types and combination of fuel combustion for cooking and heating purposes. Enhanced average concentrations of OC (240 μg/m3) and EC (118.4 μg/m3) were found with sole biomass burning (wood) on the Chullah (traditional low-budget cookstoves) due to inefficient and incomplete combustion. Although, there was a significant reduction of 53% and 41% in OC and EC respectively when a combination of biomass and Liquefied Petroleum Gas (LPG) was used for cooking. With LPG, the concentrations of OC and EC significantly declined to as low as 38.1 μg/m3 and 31.6 μg/m3 respectively. Also, an excellent inter-relationship was identified between the socio-economic parameters such as the kitchen’s ventilation, education, financial status, etc. and CA emissions. In the house with very good ventilation (2 wide windows), the total CA emissions were as low as 86.7μg/m3. Also, the family members were educated and financially affluent. On the other hand, the total CA emissions were escalated by a significant 75.9% where the ventilation facility was extremely poor (small window and slit in the roof), the family was limitedly educated, and financial status lied below poverty line. On an average, the women in this village were found to spend 5 hours per day in the kitchen area. The socio-economic parameters are necessarily important towards the mitigation indoor air pollution and hence carbonaceous aerosols.

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