ABSTRACT. - PM2.5 and PM10 levels in some Cluj-Napoca`s crossroads. Particulate matter (PM) is the term used for a mixture of solid particles and liquid droplets suspended in the air. These particles originate from a variety of sources, such as power plants, industrial processes, and diesel trucks, and they are formed in the atmosphere because of the transformation of gaseous emissions. For these two classes of PM are taken into account: PM10 to describe particles of 10 micrometers or less and PM2.5 represents particles less than 2.5 micrometers in aerodynamic diameter. Due to their significant health problems, United States Environmental Protection Agency (USEPA) has introduced some standards that regard to the maximum values accepted in the outdoor air. These standards include values for 24 hour and one year time. The variation of PM10 and PM2.5 levels in some crossroads from Cluj-Napoca is presented in this study. According to our data for PM10 the main values of short determination (15 minutes) varied between 18 and 164 μg/m3 air depending to the point of determination and to the meteorological parameters. Regarding to PM2.5 the main values of short determination (15 minutes) varied between 0,081 and 64 μg/m3 air.
Key words: PM, sources, urban areas
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