IISection
5.1 IntRoduCtIon
as fuel for daily household cooking (WHO, 2002). Its use is much more in the Indian subcontinent. For example, biomass accounts for more than 80% of the domestic energy in India. The users are poor people and cooking is usually done in traditional chullahs (stoves), which are inefficient and emit large quantities of smoke indoors (Figure 5.1). Coupled with these, the cooking areas are often poorly ventilated, which results in greater exposure to combustion fumes (IIPS, 1995). A survey conducted jointly by the National Council of Applied Economic Research and World Bank in 1996 has reported that about 578 million tons of biomass is used annually in India as a source of domestic energy of which wood constitutes 52%, animal dung 21%, and agricultural refuse 20%. In general, rural domestic sector in India uses 1.2–2.1 kg of biomass/capita/day (Smith, 1987).
fIguRe 5.1 Photographs showing (a) collection of biomass fuel and (b) cooking with it in open chullah (oven) in rural India.
In West Bengal, where the study has been carried out, 45.6 million tons of bio- mass is used annually for cooking and room heating (Reddy and Venkataraman, 2002). Firewood remains the mainstay of biomass fuel in the state with an annual usage of 23.3 million tons/year, followed by agricultural wastes (11.9 million tons/
year) and dung cakes (10.3 million tons/year) (Reddy and Venkataraman, 2002).
Biomass fuel use as a source of domestic energy is even more in Bangladesh and Nepal where 88% and 80% of the population, respectively are dependent on biomass fuels for household cooking. The percentage of users is marginally lower in Pakistan (72%) and Sri Lanka (67%; WHO, 2006).
Poverty is a strong predictor of IAP from biomass fuel use in developing coun- tries. People living in rural areas of these countries are generally poor who can ill afford cleaner fuels such as LPG with their modest income. Instead, they rely on biomass that is cheaper (or free of cost) and readily available. No wonder, there are only a handful of LPG users in rural India, and in most of the cases the LPG owners also use biomass (mixed user) to reduce fuel cost. Besides developing nations, poor people of some industrialized countries who earlier used cleaner fuels are now reverting to biomass because of political change and economic downturn. Notable examples include people residing in Tajikistan and Kyrgyz Republic after the break- down of the former Soviet Union.
5.1.2 iap from BiomaSS Burning
Biomass fuels are at the high end of the fuel ladder in terms of pollution emissions and at the low end in terms of combustion efficiency (Smith et al., 1994). Smoke emitted during biomass burning contains a wide range of pollutants including particulates, carbon monoxide (CO), oxides of nitrogen and sulfur, polycyclic aromatic hydrocar- bons (PAHs), volatile organic compounds (VOCs), and trace metals including Fe, Cu, Ni, Cr, and Pb (Zhang and Smith, 1996; Bruce et al., 2000). Airborne particles with a diameter of less than 10 µm (PM10) are hazardous because they can be inhaled deep inside the lungs and thus serve as a vehicle for toxic matters that usually adsorb onto their surface. Burning biomass emits more PM10 than LPG or electricity. For example, particle concentrations in the kitchens vary from 200 to 5000 µg/m3 of air during cooking with biomass fuels (Smith, 1993; Ezzati and Kammen, 2002) in contrast to 200–380 µg/m3 during cooking with LPG or electricity (Ellegard, 1996). Moreover, fine (aerodynamic diameter <2.5 µm, PM2.5) and ultrafine particles (diameter < 0.1 µm) constitute a bulk of the biomass smoke (Tesfaigzi et al., 2002) and most of the mass is due to the presence of fine particles, that is, PM2.5, which is more harmful for human health than is PM10 (WHO, 1999). Biomass is considered even more harmful than diesel, because biomass smoke contains 10 times more mass concentration of respi- rable particles having a diameter of 0.5–0.8 µm compared with diesel (Venkataraman and Rao, 2001).
In a typical biomass-using Indian kitchen, the concentration of PM10 ranged from 500 to 2000 µg/m3 during cooking (Balakrishnan et al., 2002). Similarly, in Nepalese households, PM10 level in kitchens using biomass fuels was about three times higher than that in those using cleaner fuels such as kerosene, LPG, and biogas (Srestha and Srestha, 2005). The type of fuel, oven type, and ventilation have a significant impact
on indoor air quality. Compared with wood, combustion of dung cakes and briquette emitted significantly higher CO and particulate matter (Venkataraman and Rao, 2001). In rural India, the ovens are not vented outside, kitchens are often poorly ventilated, and half of the households do not have separate kitchens (Mishra et al., 1999). These factors contribute significantly to high particulate level in cooking areas.
5.1.3 HealtH impactof BiomaSS Smoke expoSure: exceSS
morBidityand mortality
Chronic exposure to biomass smoke is one of the most important environmental and public health problems in developing countries, especially in women who cook with these fuels and their children who attend to the fires or stay close to their mothers during cooking (Smith and Mehta, 2000; Smith, 2002). Cumulative exposures to high levels of particulate pollutants could be hazardous for the biomass users, because 1% increase in total daily mortality occurs for every 20 µg/m3 increase in PM10 level in breathing air (Samet et al., 2000). It has been estimated that IAP from biomass use in developing countries is responsible for 4–5% of global burden of disease for both deaths and disability adjusted lost life years (DALYs) from acute respiratory infec- tions (ARI), chronic obstructive pulmonary disease (COPD), tuberculosis, asthma, lung cancer, ischemic heart disease, and blindness (Smith and Mehta, 2003).
Globally, over 1.2 million (Smith and Mehta, 2003) to about 2.8 million prema- ture deaths per year (Bruce et al., 2000) have been attributed to biomass fuel use.
World Health Organization (WHO) has put the mortality figure to 2.2–2.5 million annually (WHO, 1997). The problem is escalating with the passage of time and the number of annual premature deaths due to IAP from biomass fuel use has been projected at 9.8 million by the year 2030 (Bailis et al., 2005). In India, IAP from biomass combustion contributes to 4–6% of the national burden of disease and 400,000–550,000 premature deaths every year (Smith, 2000).
5.1.4 ScopeoftHe workand oBjectiVeoftHe Study
Many PAHs and VOCs present in biomass smoke, such as benzo(a)pyrene [B(a)P] and benzene, are potential human carcinogens (Zhang and Smith, 1996). It has been esti- mated that women in India who cook regularly with biomass are on average exposed to a B(a)P that is equivalent to smoking 2–20 packs of cigarettes per day (Smith and Liu, 1994). It is reasonable to assume therefore that the womenfolk of the developing countries who are chronically exposed to air contaminated with chemicals emitted from combustion of biomass are at a considerable health risk. However, the level of IAP from biomass fuel use in rural households in India, its effects on respiratory and systemic health of the women who cook with these fuels, and the possible mechanism of such effects at the cellular and subcellular levels are largely unknown as very little attention has been paid to this important public health issue by the clinicians, scien- tists, and administrators. In view of this, the present work was undertaken to evaluate the health impact of IAP from biomass fuel use among rural women in India who used to cook with these fuels. The objective was to prepare a database on respiratory and systemic health impairments in association with biomass use in the country and
to search for biomarkers of pollution exposure and effect suitable for biomonitoring of health impact of air pollution in the country.
5.2 study pRotoCol