Urban air quality is getting worse due to high levels of particulate matter (PM) in cities. These particles come from various sources like combustion, transport, and industry. A study in Žilina, Slovakia, looked at different PM sources by measuring PM fractions and analyzing chemical elements. They found that road traffic is the main source of PM10 in the city. During winter, PM10 levels were highest on Komenského Street. Coarse PM2.5-10 contained elements like Mg and Fe, while fine PM2.5 had elements like K and Zn. The study used statistical methods to identify road transport as the main PM10 source in Žilina.