Personal exposure to aerosols for women in urban households

It is being realized recently, that indoor sources are a greater threat to human health than outdoor sources, since people, especially women and children, spend larger percentage of their time inside homes. The most dominant source of indoor air pollution is domestic cooking. The aim of this study was to measure indoor air pollutants in typical middle income urban households using LPG as cooking fuel. Monitoring was done in three microenvironments viz. kitchen, living room and outdoors for cooking and non-cooking hours so that total personal exposure could be assessed. Meteorological parameters of wind, temperature and humidity were also measured. The results showed that the concentration of gaseous pollutants like CO and NOx in the kitchen during cooking was above the standards. Particulates during non-cooking periods in kitchens were mostly found in coarser mode (Mass Median Aerodynamic Diameter, 1.04µm) with an average mass fraction 0.69. The cooking generated very high concentration of particles,about 4 to 5 times more than the non-cooking periods, with almost all of the particulate mass in the submicron size range. Particulate size distributions showed bimodal characteristics for both cooking and non-cooking periods. Accumulation mode (0.05-0.2µm) was found predominant during cooking and the coarse mode found predominant for non cooking periods. The concentration of PM5 was very high and above standard during cooking as well as during non-cooking hours. Taking into account the time activity pattern of the respondents, personal exposure was also estimated. It was found that cooking contributed upto 40% of the total exposure for women. There was considerable variation in exposure between houses due to factors like type of food cooked, placement of stove, size of kitchen and most prominently because of direction of cross ventilation and air exchange rate.