INDOOR RESIDENTIAL NITROGEN-DIOXIDE CONCENTRATIONS IN BAHRAIN

A total of 128 passive diffusion tube samplers have been used to measure the average concentrations of nitrogen dioxide inside and outside of 32 homes in Bahrain. The tubes were placed for a period of 14 days. Nitrogen dioxide in the kitchen, hall, bedroom, and outdoors averaged 52.3, 22.1, 15.2, and 26.0-mu-g/m3, respectively. The overall mean of the indoor concentrations was 29.8-mu-g/m3, and the mean indoor/outdoor ratio was 1.2. A significant positive correlation was found between the concentrations of NO2 in the kitchen and the number of meals cooked per week. In 6% of the houses, the average kitchen NO2-levels were higher than the U.S. National Ambient Air Quality Standard of 100-mu-g/m3. All houses had liquefied petroleum gas (LPG) cookers with the exception of one which used an electric cooker. The mean levels of NO2 in this house were 14.5, 10.5, 11.5, and 28.2-mu-g/m3 in the kitchen, hall, bedroom, and outdoors. The results of the study show that indoor sources of NO2 contribute more than outdoor sources to the overall concentrations of NO2 in the houses in Bahrain.