Atmospheric concentration, temporal and spatial variations, and sources identification of persistent organic pollutants in urban and semi-urban areas using the passive air samplers

In this study, the ambient persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) concentrations were measured for 12 months at urban and semi-urban areas using the passive air sampler. During the sampling period, a total of 14 PAH (∑14PAH) concentrations measured in urban and semi-urban areas were found as 54.4 ± 22.6 ng/m3 and 51.7 ± 34.3 ng/m3, respectively. Molecular diagnostic ratios (MDRs) were used to determine PAH sources. According to the MDR values, combustion sources are the most important PAH sources in both sampling areas. However, since the urban area is close to the industrial zone, the combustion sources occurred at high temperatures (> 800 oC), while the semi-urban area generally consisted of burning petrogenic fuels. ∑50PCB concentrations measured in the urban and semi-urban areas were found as 522.5 ± 196.9 pg/m3 and 439.5 ± 166.6 pg/m3, respectively. Homologous group distributions were used to determine the source of PCBs. According to homologous group distributions, Tri-, Tetra-, and Penta- chlorinated PCBs were dominant in both sampling areas. ∑10OCP concentrations measured in urban and semi-urban areas were found as 242.5 ± 104.6 pg/m3 and 275.9 ± 130.9 pg/m3, respectively. Also, α-HCH/γ-HCH and β-/(α + γ)-HCH ratios were used to determine the source of OCPs. Lindane was the predominated OCP in both sampling areas.

PM2.5 Magnetic Properties in Relation to Urban Combustion Sources in Southern West Africa

The physico-chemical characteristics of particulate matter (PM) in African cities remain poorly known due to scarcity of observation networks. Magnetic parameters of PM are robust proxies for the emissions of Fe-bearing particles. This study reports the first magnetic investigation of PM2.5 (PM with aerodynamic size below 2.5 μm) in Africa performed on weekly PM2.5 filters collected in Abidjan (Ivory Coast) and Cotonou (Benin) between 2015 and 2017. The magnetic mineralogy is dominated by magnetite-like low coercivity minerals. Mass normalized SIRM are 1.65 × 10−2 A m2 kg−1 and 2.28 × 10−2 A m2 kg−1 for Abidjan and Cotonou respectively. Hard coercivity material (S-ratio = 0.96 and MDF = 33 mT) is observed during the dry dusty season. Wood burning emits less iron oxides by PM2.5 mass when compared to traffic sources. PM2.5 magnetic granulometry has a narrow range regardless of the site or season. The excellent correlation between the site-averaged element carbon concentrations and SIRM suggests that PM2.5 magnetic parameters are linked to primary particulate emission from combustion sources.

Comprehensive organic emission profiles, secondary organic aerosol production potential, and OH reactivity of domestic fuel combustion in Delhi, India

This study examines the volatility distribution of organic emissions from solid fuel combustion sources from Delhi, India, and examines the chemical drivers of the OH reactivity and the secondary organic aerosol production potential.

Size-resolved exposure risk of persistent free radicals (PFRs) in atmospheric aerosols and their potential sources

Environmentally persistent free radicals (EPFRs) are a new type of substance with potential health risks. EPFRs are widely present in atmospheric particulates, but there is a limited understanding of the size-resolved health risks of these radicals. This study reports the exposure risks and source of EPFRs in atmospheric particulate matter (PM) of different particle sizes (<10 µm) in Linfen, a typical coal-burning city in China. The type of EPFRs in fine particles (< 2.1 µm) is different from that in coarse particles (2.1–10 µm) in both winter and summer. However, the EPFR concentration is higher in coarse particles than in fine particles in summer, and the opposite trend is found in winter. In both seasons, combustion sources are the main sources of EPFRs, with coal combustion as the major contributor in winter, while other fuels are the major source in summer. Dust contributes part of the EPFRs, and it is mainly present in coarse particles in winter and the opposite in summer. The upper respiratory tract was found to be the area with the highest risk of exposure to EPFRs of the studied aerosols, with an exposure equivalent to that of approximately 21 cigarettes per person per day. Alveolar exposure to EPFRs is equivalent to 8 cigarettes per person per day, with combustion sources contributing the most to EPFRs in the alveoli. This study helps us to better understand the potential health risks of atmospheric PM with different particle sizes.