Characteristics of indoor/outdoor particulate pollution in urban and rural residential environment of Pakistan.

UNLABELLED: Particulate pollution has emerged as a serious environmental health concern in Pakistan. The use of biomass fuels in traditional stoves produces high levels of indoor air pollutants. In Pakistan, 94% of rural and 58% of urban households depend on biomass fuel. This study investigates variations in indoor/outdoor concentrations of particulate matter during various activities for three different micro-environments in Pakistan. At a rural site, the average indoor/outdoor ratios for PM(10), PM(2.5), and PM(1), in kitchens using biomass fuels were 3.80, 4.36, and 4.11, respectively. A large variation was recorded in the mass concentration of particulate matter during cooking with concentrations in the range 4000-8555 microg/m(3). In a living room at a rural site, the average indoor/outdoor ratios for PM(10), PM(2.5), and PM(1) were 1.74, 2.49, and 3.01, respectively. At the urban site, the average indoor/outdoor ratios for the same size fractions were 1.71, 2.88, and 3.47, respectively. Cooking, cleaning and smoking were identified as principal contributors to the high indoor levels of particulate matter. This study showed considerably high concentrations of particulate matter, particularly in kitchens using biomass fuels, as compared to living areas. Thus women and children face the greatest exposure due to the amount of time they spend in the kitchen. PRACTICAL IMPLICATIONS: In the developing world, particulate air pollution, both indoor and outdoor, is a substantial health hazard to the public. The very high concentrations of particulate matter in both rural and urban sites, particularly in kitchens using biomass fuels, emphasize the severity of this issue in Pakistan. Women and children are extensively at risk due to amount of time spent in kitchens. This state of affairs calls for a large-scale intervention to reduce the exposure to indoor air pollution.