PREDICTION OF AEROSOL PARTICLE SIZE DISTRIBUTION FROM THE MEAS-URED VALUES OF PM2.5 AND PM10

Introduction. Ambient air pollution with particulate matter from various sources sig-nificantly increases the risk of human health disorders. The concentrations of the total suspended particles (TSP), as well as the PM2.5 and PM10 fractions, are mainly monitored. In fact, the ac-tual size distribution of aerosol particles differs significantly from the stepwise distribution formed only by the concentrations of PM2.5 and PM10. Aim of the study: development of a method for reconstructing the size distribution function of aerosol particles from the actual concentrations of PM2.5 and PM10 under the assumption of a lognormal size distribution for calculation of doses deposited in different lung regions. Methods. Long-term concentrations of various fractions of particles in the ambient air were ob-tained from the database of social and hygienic monitoring created by the "Center for Hygiene and Epidemiology in the Republic of Tatarstan (Tatarstan)". A reconstructed theoretical particle size distribution function f0(dp) was derived using the numerical solution, and the corresponding software was developed. The MPPD (Multiple-Path Particle Dosimetry) software was used to calculate the particle deposited doses in different areas of the human respiratory tract. Results. The measured values of the PM2.5 and PM10 concentrations were used to derive the lognormal aerosol size distribution. Based on the calculation of the mass doses of settled particles in the human respiratory system using MPPD (Multiple-Path Particle Dosimetry) code, it is shown that the calculation based only on the values of PM2.5 and PM10 leads to an underestimation of the mass fractions of particles in the lower respiratory tract and alveolar zone, the values of which are determinant for the estimation of the risk of lung disease. Conclusions. The proposed method for reconstructing the size distribution function of the con-centration of aerosol particles is important for a quantitatively reliable assessment of the risks of exposure to ambient air aerosols, making it possible to move from assessment of external expo-sures to the calculation of deposited fractions. The use of deposited fractions as an exposure pa-rameter increases the accuracy of health risk assessments associated with particulate matter ex-posure. This approach can be used both in the study of ambient aerosols and for the air of the working area.