| Summary: | Vehicle traffic pollution requires complex physicochemical analysis besides emission level measuring. The current study is focused on two campaigns of emissions measurements held in May and September 2019 in Alba Iulia City, Romania. There was found a significant excess of PM<sub>2.5</sub> for all measuring points and PM<sub>10</sub> for the most circulated points during May, along with significant VOC and CO<sub>2</sub> emissions. September measurements reveal threshold excess for all PM along with increased values for VOC and CO<sub>2</sub> emissions. These are the consequences of the complex environmental interaction of the traffic. Street dust and air-suspended particle samples were collected and analyzed to evidence the PM<sub>2.5</sub> and PM<sub>10</sub> sources. Physicochemical investigation reveals highly mineralized particulate matter: PM<sub>2.5</sub> fractions within air-suspended particle samples predominantly contain Muscovite, Kaolinite, and traces of Quartz and Calcite, while PM<sub>10</sub> fractions within air-suspended particle samples predominantly contain Quartz and Calcite. These mineral fractions originate in street dust and are suspended in the atmosphere due to the vehicles’ circulation. A significant amount of soot was found as small micro-sized clusters in PM<sub>2.5</sub> and fine micro-spots attached over PM<sub>10</sub> particles, as observed by Mineralogical Optical Microscopy (MOM) and Fourier Transformed Infrared Spectroscopy (FTIR). GC-MS analysis found over 53 volatile compounds on the investigated floating particles that are related to the combustion gases, such as saturated alkanes, cycloalkanes, esters, and aromatic hydrocarbons. It proves a VOC contamination of the measured particulate matters that make them more hazardous for the health. Viable strategies for vehicle traffic-related pollutants mitigation would be reducing the street dust occurrence and usage of modern catalyst filters of the combustion gas exhausting system.
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