Indoor air quality in Bulgaria

High temperature combustion is the main source of nitric oxide (NO) and nitrogen dioxide (NO2) in the air. Unvented gas and kerosene cooking appliances and space heaters are found to be the major indoor emission sources. It is important to know the level of exposure to NO2 in order to study their effects on health, to establish dose-effect relationships and to devise appropriate pollution control strategies. Recognising these problems prompted a project which aimed to study the exposure to NO2 among children aged 10-12 years living in 4 settlements in Bulgaria. The group of children investigated, whose parents included both smokers and non-smokers, came from homes with different types of heating and cooking appliances. The study was based on questionnaires-diaries. Palmes tubes were used for monitoring both personal exposure to NO2 and the levels indoors (kitchen, living room) and outdoors. The data obtained from the study showed that the concentrations of NO2 were highest in homes which had gas cooking stoves and in which the parents were smokers.