Concentrations of aliphatic and polycyclic aromatic hydrocarbons in ambient PM_2.5 and PM₁₀ particulates in Doha, Qatar

Abstract

Organic carbon (OC), elemental carbon (EC) and ninety organic compounds (36 polycyclic aromatic hydrocarbons (PAHs), 25 n-alkane homologues, 17 hopanes and 12 steranes) were concurrently quantified in atmospheric particulate matter of PM and PM. The 24-hr PM samples were collected using Harvard Impactors at a sub-urban site in Doha, Qatar from May to December 2015. The mass concentrations (mean ± standard deviation) of PM and PM were 40 ± 15 and 145 ± 70 µg m, respectively, exceeding the World Health Organization (WHO) air quality guidelines. Coarse particles comprised 70% of PM. Total carbonaceous contents accounted for 14% of PM and 10% of PM particulate mass. The major fraction (90%) of EC was associated with the PM. Conversely, 70% of OC content was found in PM fraction. The secondary OC accounted for 60-68% of the total OC in both PM fractions, indicating photochemical conversions of organics are much active in the area having higher air temperatures and solar radiations. Among the studied compounds, n-alkanes were the most abundant group, followed by PAHs, hopanes, and steranes. n-alkanes from C to C prevailed with a predominance of odd carbon numbered congeners (C-C). High-molecular-weight PAHs (5-6 rings) also prevailed, within their class, with benzo[b + j]fluoranthene (Bb+ jF) being the dominant member. PAHs were mainly (by 80%) associated with the PM fraction. Local vehicular and fugitive emissions were predominant during low-speed southeasterly winds from urban areas, while remote petrogenic/biogenic emissions were particularly significant under prevailing northwesterly wind conditions.

Potential role of polycyclic aromatic hydrocarbons as mediators of cardiovascular effects from combustion particles

“…PAHs are the most well-known of these chemicals [17]. Other known chemical groups include n-alkanes, hopanes and steranes [18].…”

Source apportionment of organic pollutants in fine and coarse atmospheric particles in Doha, Qatar

“…The measured species concentrations and their variations at the sampling site were reported in our previous study (Javed et al 2019). Here we presented the results of source apportionment analysis to apportion ambient organic pollutants concentrations to the contributing sources.…”

“…The current receptor modeling for the source apportionment was conducted using PM composition dataset from an 8-month air sampling campaign conducted in Doha, Qatar during May-December (Javed et al 2019).…”

“…Detailed information about the ambient sampling and chemical characterization can be found in Javed et al (2019). Briefly, Twenty-four-hour PM 2.5 and PM 10 filter samples were simultaneously collected every second day for PM mass measurement and EC/OC analysis, and a total of 105 PM 2.5 and 105 PM 10 samples were collected.…”

“…PM-bound organic compounds (36 polycyclic aromatic hydrocarbons (PAHs), 25 n-alkane homologs, 17 hopanes, and 12 steranes) were measured by an Agilent 6890N Gas Chromatograph, coupled with an Agilent 5973A Inert Mass Selective Detector. The sampling protocol, sample analysis procedures and detailed quality assurance data were previously presented in a companion paper by our research group (Javed et al 2019).…”