Polycyclic aromatic hydrocarbons in PM10, PM2.5 and PM1 particle fractions in an urban area

Inhalation of atmospheric polycyclic aromatic hydrocarbons (PAHs) bound to particulate matter can have adverse effects on human health. Particle size plays an important role in assessing health risks. The aim of this study was to compare concentrations of PAHs in different particle fractions. Measurements of PAHs were carried out in Zagreb, the capital of Croatia (~ 790,000 inhabitants). The measuring station was located in the northern, residential part of Zagreb, close to a street with modest traffic density. Twenty-four-hour samples of PM10, PM2.5 and PM1 particle fraction were collected on quartz filters using a low-volume sampler from about 50 m3 of air. Three fractions were collected from January to December 2013. The analysis was performed using high-performance liquid chromatography (HPLC) with a fluorescence detector and time-programmed changes in excitation and emission. Comparison of PAH content in PM10 and PM2.5 particle fractions revealed that more than 80% of PAHs measured in winter were bound to the smaller particle fraction (PM2.5), except for Chry, IP and DahA. In summer, more than 60% of measured PAHs were bound to PM2.5 particles, except for DahA, while in spring, more than 50% of measured PAHs were bound to PM2.5 particles, except for Flu, BaP and BbF. Furthermore, comparing PAH content in PM1 and PM2.5 fractions, we found that most PAHs were bound to particle fraction PM1, and the percentage of PAHs in PM1 was the highest in winter (more than 90%). Factor analysis showed that most of the PAHs bound to PM10, PM2.5 and PM1 probably had identical sources in winter, spring and summer (house heating and traffic), and the only significant difference in origin was found in autumn for PAHs bound to PM2.5 and PM1 fractions.