Exploring the patterns of particle-bound PAHs in ambient air of an urban agglomeration (first results)

This study examines the occurrence of polycyclic aromatic hydrocarbons (PAHs) in PM10 atmospheric particles in an urban environment, Ioannina, Greece (population: ~114.000). A one-year sampling campaign, spanning from March 2022 to April 2023, was conducted. Fifty-seven 24-hour samples representing both warm and cold periods were collected and sixteen PAHs, including those regulated by the revised Ambient Air Quality Directive (EU) 2024/2881, were quantified. The winter-to-summer PAH concentration ratio was calculated, and correlation analysis was conducted with PM10-bound PAHs and other pollutants to identify potential common sources. Molecular diagnostic ratios of PAH isomers were employed to assess the impact of well-characterized emission sources such as vehicular traffic and biomass burning. Compounds within each ratio share identical molar masses, suggesting similar environmental behavior and fate. Low-temperature processes, such as wood burning, produce low molecular weight PAHs, while high-temperature processes, like fuel combustion in vehicles, release higher molecular weight PAHs. Meteorological parameters, including temperature, relative humidity, atmospheric pressure, precipitation and wind velocity, were also considered. The first results of the sampling campaign are presented aiming to offer insights into air quality in non-industrialized urban areas affected by PM pollution episodes during cold, steady and calm atmospheric conditions.