MONITORING OF SIZE-SEGREGATED PARTICULATE MATTER FRACTIONS WITH OPTICAL INSTRUMENTS IN URBAN AREAS

The assessment of harmful PM concentrations i.e. particles with an aerodynamic diameter below 2.5 mu m, requires continuous monitoring conducted for 24 hours a day, for 365 days a year. Monitoring campaigns for screening the PM levels in a particular urban area facilitate the conceiving of a continuous monitoring plan by establishing where to deploy optimally the optical instruments for on-line measurement. The paper presents the practical efficiency of the outdoor monitoring of PM size fractions using a new optical equipment i.e. Dusttrak DRX 8533 with environmental enclosure and heating module. The experiments were carried out in Targoviste city, Romania, between 2014 and 2015 within the first two phases of the ROkidAIR project (http://www. rokidair. ro) to perform a screening of the PM concentrations existing in these urban areas and to calibrate the prototype of the PM2.5 microstation developed within the project. The utilization of the DustTrak instrument showed that in heavy traffic conditions without significant industrial emissions, the most frequent PM fraction is the submicrometric one (PM1). The results pointed out the usefulness of monitoring four size segregated mass fractions and their relationship with the potential PM emission sources. Outdoor PM2.5 measurements provide key information for evaluating population exposure, planning of air quality and establishing of reliable measures that allow the lowering of PM emission.