МакедонскиSuspended particles consist of solids in the air in the form of smoke, dust and vapor, and can stay suspended for an extended period. These air particles are categorized according to the size and, at the same time, they are one of the main reasons for reduced visibility. Particles with size in diameter smaller than 50 micrometers are classified as total suspended particles (TSP). PM2.5 are so called fine particles with a size smaller or equal to 2.5 micrometers.
PM2.5 derive directly from the emission of primary particles, or is formed through secondary reactions which include VOCs, SO2 и NOX emissions deriving from energy and industrial plants, automobiles (especially trucks and buses using diesel fuels) and other combustion sources. As we can see from the figure during the winter time PM2.5 concentrations in towns and cities throughout the country are higher than the concentrations in spring period of the year, as presented on the graph. This is also like PM10 caused by a different types of emission from the production processes, traffic, residential wood burning, agricultural burning and etc. combined with the unfavorable meteorological conditions. PM2.5 is carried by the wind, so particulate matter generated in one state can affect PM2.5 levels in downwind areas.
