Seasonal and Fractional Variability of Particle-bound PAHs in an Urban Environment

Air Monitoring, Methods, and Technology
Oral Presentation

Prepared by I. Han1, J. Lee2, M. Afshar3, W. Su3
1 - Temple University College of Public Health, Department of Epidemiology and Biostatistics, 1301 Cecil B. Moore Avenue, Philadelphia, PA, 19122, United States
2 - University of Texas Health Science Center (UTHealth) at Houston, , , United States
3 - University of Texas Health Science Center at Houston (UTHealth), , , United States

Contact Information: [email protected]; 215-204-4766


It is important to have a better understanding of exposure to combustion-related airborne organic chemicals in different sizes since health effects may vary depending on the deposition of organic chemicals in human airways. The aim of this study was to characterize seasonal and fractional variability of particle-bound polycyclic aromatic hydrocarbons (PAHs) in an urban area with industrial facilities and heavily trafficked roadways. Size-fractionated ambient air samples were collected at three locations using an 11-stage cascade impactor in Houston, Texas, from June 2021 to March 2022. The size of collected particle-bound PAHs ranged from < 100 nm (ultrafine particles) to 18 micrometers (coarse size). Preliminary results showed that overall mean concentrations of the sum of 18 PAHs were 210±73 pg/m3. Naphthalene was the highest (72±24 pg/m3) followed by dibenzo[a,h]anthracene (38±30 pg/m3), phenanthrene (16±6.1 pg/m3), and the rest of PAHs. Of 18 PAHs, two and three rings of PAH comprised 56%, followed by 5-ring PAHs (23%), 6-ring PAHs (10%), and 4-ring PAHs (9%). The sum of 18 PAHs during the warm season (May to September) was 22% higher than the cool season (October to April). Traffic sources were primarily attributed to ambient air PAHs during the warm season whereas traffic and industrial activities mainly contributed to airborne PAHs during the cool season. Size-fractionated PAHs in fine-size bins (0.1 – 3.2 micrometers), ultrafine size bins (<0.1 micrometers), and coarse-size bins (> 3.2 micrometers) consisted of 61%, 21%, and 18% of total PAHs, respectively. The results will be useful for developing a lung deposition model to evaluate personal exposure to combustion-related air pollutants and human health risks in urban areas.