[Evaluation of the MPEL for SO2 and NO2 and the development of new MPELs for atmospheric pollutants based on modern epidemiological, ecological and toxicological studies].

Proceeding from modern experimental and natural observations on the effect of sulphur dioxide and nitrogen dioxide on live organism and environment, the now, operative in Bulgaria maximum allowable concentrations of these contaminants are reassessed. The maximal single and mean diurnal SO2 MAC are proposed to be reduced to 0.15 mg/m3 and 0.03 mg/m3, while those of NO2 remain the same. Based on data available in modern literature and equations proposed by the authors for express determination of MAC for some atmosphere contaminants, MAC for some nonstandardized contaminants in Bulgaria are suggested: ozone (maximal single - 0.06 mg/m3 and mean diurnal - 0.03 mg/m3 asbestos (mean dirnal - 0.25 fibers/cm3), zinc (mean diurnal - 0.05 mg/m3, copper (mean diurnal - 0.01 mg/m3. The use of mathematical equations for determination of MAC of differrent hydrocarbons is suggested.