Concentration and Photochemistry of PAHs, NPAHs, and OPAHs and Toxicity of PM_2.5 during the Beijing Olympic Games

Abstract

Atmospheric particulate matter with diameter <2.5 um (PM2.5) was collected at Peking University (PKU) in Beijing, China before, during, and after the 2008 Olympics and analyzed for black carbon (BC), organic carbon (OC), lower molecular weight (MW<300) and MW302 Polycyclic Aromatic Hydrocarbons (PAHs), nitrated PAHs (NPAHs) and oxygenated PAHs (OPAHs). In addition, the direct and indirect acting mutagenicity of the PM2.5 and the potential for DNA damage to human lung cells were also measured. Significant reductions in BC (45%), OC (31%), MW< 300 PAH (26% – 73%), MW 302 PAH (22% – 77%), NPAH (15% – 68%) and OPAH (25% – 53%) concentrations were measured during the source control and Olympic Olympic period. However, the mutagenicity of the PM2.5 was significantly reduced only during the Olympic period. The PAH, NPAH, and OPAH composition of the PM2.5 was similar throughout the study, suggesting similar sources during the different periods. During the source control period, the parent PAH concentrations were correlated with NO, CO, and SO2 concentrations, indicating that these PAHs were associated with both local and regional emissions. However, the NPAH and OPAH concentrations were only correlated with the NO concentrations, indicating that the NPAH and OPAH were primarily associated with local emissions. The relatively high 2-nitrofluoranthene/1-nitropyrene ratio (25 – 46) and 2-nitrofluoranthene/2-nitropyrene ratio (3.4 – 4.8), suggested a predominance of photochemical formation of NPAHs through OH-radical-initiated reactions in the atmosphere. On average, the ΣNPAH and ΣOPAH concentrations were 8% of the parent PAH concentrations, while the direct-acting mutagenicity (due to the NPAH and OPAH) was 200% higher than the indirect-acting mutagenicity (due to the PAH). This suggests that NPAH and OPAH make up a significant portion of the overall mutagenicity of PM2.5 in Beijing.

Molecular distribution and seasonal variation of hydrocarbons in PM2.5 from Beijing during 2006

“…It is well known that most PAHs are mutagenic and carcinogenic to humans (Wang, Jariyasopit, et al, 2011;Xie et al, 2009). The health risks of PAHs can be assessed by calculating BaP-equivalent (BaPE) concentrations as follows:…”

“…For example, diagnostic ratios of normal alkanes (n-alkanes) and polycyclic aromatic hydrocarbons (PAHs) can indicate whether these compounds were produced from the combustion of fossil fuels or from the release of epicuticular waxes from higher plants (Li et al, 2012;Wang, Kawamura, Xie, et al, 2009). Another characteristic of organic aerosols that has led to increased concern over their sources and loadings is their toxicity; PAHs for instance, are mutagenic and carcinogenic for humans (Wang, Jariyasopit, et al, 2011;Xie et al, 2009).…”

Oxygenated, nitrated, methyl and parent polycyclic aromatic hydrocarbons in rivers of Haihe River System, China: Occurrence, possible formation, and source and fate in a water-shortage area

“…1-nitropyrene was found in a drinking water source of Japan with a relatively low concentration (1 ng/L), accounting for 1% of the total genotoxicity (Ohe and Nukaya, 1996). Wang et al (2011a) reported that the direct acting mutagenicity of Beijing particulate matter (PM) caused by the OPAHs and NPAHs was 2 times higher than that of the indirect mutagenicity caused by the PAHs, though the OPAH and NPAH concentrations only contributed 8% to the total PAH concentrations. In polluted river sediment, the fraction of the extracts containing the polar PAHs (including NPAHs) showed higher toxicities than those containing the non-polar PAHs like PAHs (Lübcke-von Varel et al, 2011).…”

“…Studies on the OPAHs and NPAHs in the atmospheric and soil environment have been much more common than those in the aquatic environment (Smith and Harrison, 1996;Dimashki et al, 2000;Lundstedt et al, 2006;Wang et al, 2011a;Wei et al, 2012). The SPAHs might enter the aquatic environment through atmospheric deposition and surface runoff.…”

Distribution of atmospheric particulate matter (PM) in rural field, rural village and urban areas of northern China

“…Due to heavy dependence on coal for energy in China (NBSC, 2008), emissions of various activities are often very high. In general, air pollution is more severe in the north than that in the south because heating is required in north for several months in winter (Liu et al, , 2008Wang et al, 2011a;Zhang et al, 2009) and north China is affected by spring sandstorms much more often than the south (Sun et al, 2001). It is often believed that air pollution occurs mainly in cities where most power stations, industrial facilities, and motor vehicles are concentrated.…”