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CONCENTRATIONS AND GAS-PARTICLE PARTITION OF POLYCYCLIC AROMATIC HYDROCARBONS IN AMBIENT AIR OF A MEDIUM-SIZED ANDEAN CITY
Camilo Zapata Mora, Jesús Alberto Angulo Cuero, Marco Tadeu Grassi, Rafael Garrett Dolatto, Beatriz Helena Aristizábal Zuluaga

Última modificación: 17/06/2019

Resumen


Cities in emerging countries are facing a fast growth and urbanization; however, the study of air pollutant emissions and its dynamics is scarce, making their populations vulnerable to potential effects of air pollution. This situation is critical in medium-sized urban areas. This study studied concentrations in the gas and particles phase, and gas–particle partition behavior of polycyclic aromatic hydrocarbons (PAHs) in the ambient air of the medium-sized Andean city of Manizales (398830 population and 2150 m.a.s.l.). High-volume samplers with quartz fiber filters (QFFs) and polyurethane foams (PUFs) were used to collect PAHs in both gaseous and particulate phases (TSP fraction). Monitoring was carried out in 3 zones of the city, 20 samples per site, from July to September 2018, following the TO-13A EPA method. Each site had characteristic emission sources dominated by fossil fuel combustion. The EPA's 16 priority-controlled PAHs species were measured using triple quadrupole gas chromatography equipped with a mass-selective detector (GCMS). The total PAH concentrations (particle + gas) ranged from 11.5 ng/m3 to 35.2 ng/m3 (average of 19.6 ng/m3) for the urban center site; from 7.1 ng/m3 to 33.5 ng/m3 (average of 18.0 ng/m3) for the residential/commercial site; and from 13.9 ng/m3 to 114.4 ng/m3 (average of 31.5 ngm3) for the industrial site.
The dominated concentration of PAHs in the particle fraction accounted for 64–75% of total particle-bond PAHs, including mainly: Benzo[b]fluoranthene, Benzo[ghi]perylene, Benzo[a]pyrene, Indeno[1,2,3-cd]pyrene and Pyrene. On the other hand, gaseous fraction was dominated by Phenanthrene, Pyrene, Fluoranthene, Fluorene and Naphthalene, comprising 84–86% of total gaseous PAHs. The concentration of gaseous fractions of PAHs at the three sampling sites ranged from 43% to 90% of the total PAHs in the gas–particle systems; and gaseous PAHs were predominant in 90% of the samples. The gas-particle distribution was analyzed through several approaches such as the relationship of the partitioning coefficient including ambient temperature and the logarithm of the sub-cooled vapor pressure, also the octanol-air partitioning coefficient of PAHs. Results provide the baseline for ongoing research in atmospheric modeling and urban air quality, in order to improve the understanding of these air pollutants.