Passive air sampler-derived concentrations and carcinogenic potential of PAHs in oil/gas production city (Macaé, Brazil)

Abstract

Urban centers cause atmospheric pollution and suffer the most from their emissions. Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances (PTS) that can be air transported at urban sites and impact human health, causing skin allergies, respiratory diseases, and cancer. Macaé is a southeastern Brazilian coastal city that had an intense process of urbanization and population growth due to the installation of oil companies in the 1970s. The study aimed to evaluate Macaé's air quality regarding atmospheric PAH occurrence, measured using polyurethane foam passive air samplers (PUF-PAS). PUF disks were deployed along environmental gradients during the 2018–2019 spring/summer in Macaé city and its surroundings. In total, 22 individual PAHs were analyzed by gas chromatography coupled with mass spectrometry. Total PAH air concentrations ranged from 0.3 to 3.3 ng.m-3, pointing out three- to four-membered ring compounds as the most abundant (76%). Among them, phenanthrene, anthracene, and fluoranthene had the highest air concentrations, especially at sampling sites where fossil fuel combustion seemed more prominent. Compared to other cities worldwide, the lower PAH air levels reported in this study may be linked to the influence of marine air masses. As the most carcinogenic PAH compound is benzo[a]pyrene, the results are also given in benzo[a]pyrene-equivalent (BaPeq). BaPeq ranged from 0.02 to 0.10 ng.m-3. This study indicated an environmental trend along urban-industry-background spatial transects. Even though a prominent marine air mass might contribute to efficient air pollution dispersion, in urban/industrial areas, human exposure to carcinogenic chemicals is higher, probably due to local PAH sources inside the urban perimeter of Macaé.