Occurrence and seasonal variations of organophosphate flame retardants in air and dust from college microenvironments at Qingdao, China: Implications for student's exposure and risk assessment.

Organophosphate flame retardants (OPFRs) are widely used as alternatives to brominated flame retardants in a variety of consumer products and their consumption has continuously increased in recent years. However, their concentrations and human exposures in indoor microenvironments, particularly in a university environment, have received limited attention. In this study, the concentrations and seasonal variations of 15 OPFRs were assessed in typical microenvironments of two universities, including dormitories, offices, public microenvironments (PMEs: classroom, dining hall, gymnasium and library), and laboratories on the northern coast of China. Analysis of the OPFRs in both air and dust samples indicated widespread distribution in college campuses. The average concentration of ∑15OPFRs in the winter (12,774.4 ng/g and 5.3 ng/m3 for dust and air, respectively) was higher than in the summer (2460.4 ng/g and 4.6 ng/m3 for dust and air, respectively). The dust and air samples collected from PMEs and laboratories exhibited higher concentrations of OPFRs, followed by offices and dormitories. An equilibrium was reached between dust and air in all collected microenvironments. The daily intakes of OPFRs were significantly lower than the reference dose. Dust ingestion was the primary intake pathway in the winter, while inhalation and dust ingestion were the main intake pathways in the summer. The non-carcinogenic hazard quotients fell within the range of 10-7-10-3 in both the summer and winter, which are below the theoretical risk threshold. For the carcinogenic risk, the LCR values ranged from 10-10 to 10-8, indicating no elevated carcinogenic risk due to TnBP, TCEP, and TDCP in indoor dust and air.

PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and nitrated-PAHs (NPAHs) emitted by gasoline vehicles: Characterization and health risk assessment.

Seventeen polycyclic aromatic hydrocarbons (PAHs) and eight nitrated PAHs (NPAHs) in PM2.5 and conventional gaseous pollutants exhausted from 54 in-use gasoline vehicles encompassing different emission standards (China 1 to China 5) were tested on the chassis and engine dynamometric test bench. With the increase of emission standards, a decrease in the emissions of PM2.5-bound PAHs and NPAHs was detected. The emission factors (EFs) of total PAHs and NPAHs in PM2.5 emitted by the vehicles with a mileage of >100,000 km were greater than that emitted by the vehicles with driving mileage of <100,000 km under all the five emission standards. The EFs of PM2.5-bound PAHs and NPAHs emitted from port fuel injection engines were larger than that from gasoline direct injection engines. The emissions of PM2.5-bound PAHs and NPAHs were less correlated with the exhaust of CO, while the hydrocarbon (HC) emissions were strongly correlated with the PM2.5-bound PAHs emissions. The emissions of NPAHs and NOx had an inverse correlation. The toxic (TEQs) of total PAHs and NPAHs in China 3, China 4 and China 5 were significantly reduced compared to China 1 and China 2, which may be related to exhaust technology improvements. Although the EFs of NPAHs were significantly lower than those of PAHs, the TEQs of NPAHs were higher, which indicates that the toxic effect of NPAHs emitted by gasoline vehicles were stronger than PAHs.

Seasonal variations and inhalation risk assessment of short-chain chlorinated paraffins in PM2.5 of Jinan, China.

Short-chain chlorinated paraffins (SCCPs) were added to the Stockholm Convention on Persistent Organic Pollutants (POPs) at the eighth meeting of the conference of the parties in 2017. As a consequence, increasing environmental attention and international regulation on SCCPs is expected in the future. Inhalation uptake of particulate matter (PM) was an important exposure pathway for POPs into the human body. In the present study, a total of eighty PM2.5 samples were collected in the four seasons of the year at an urban site (Shandong University, Jinan) in Shandong province to investigate the seasonal changes of SCCPs and their inhalation exposure risks to human health. The concentrations of SCCPs ranged from 9.80 to 105 ng m-3, with the mean value of 38.7 ng m-3. The highest concentrations of SCCPs were detected in winter, while the lowest concentrations were in summer. SCCPs concentrations were positively correlated with the mass concentrations of PM2.5 (r = 0.629, p < 0.01), and negatively correlated with the ambient temperature (r = -0.447, p < 0.01). The SCCPs congeners with 10 carbon atoms (C10 congeners) and 7 chlorine numbers (Cl7 congeners) were the predominant congeners, which contributed 35% and 37% of the total SCCPs contamination, respectively. The average inhalation exposure was estimated to be 1.75 × 10-4 mg kg-1 day-1 for adults, which is much lower than the "no observed adverse effect level" (NOAEL) of 100 mg kg-1 day-1 given by European risk assessment for SCCPs.

Nitro and oxy-PAHs bounded in PM2.5 and PM1.0 under different weather conditions at Mount Tai in Eastern China: Sources, long-distance transport, and cancer risk assessment.

Fourteen nitro-PAHs and five oxy-PAHs associated with PM2.5 and PM1.0 were analyzed by GC-MS/MS at Mount Tai, China. 85% of the nitro-PAHs and 65% of oxy-PAHs were found in PM1.0. The combined concentration of nitro-PAHs in PM2.5 was highest in air masses associated with biomass burning (270.50pg/m3) compared with measurements from heavily polluted days (93.21pg/m3) and clean days (81.22pg/m3). A similar trend was also reflected in measurements of PM1.0. 9-FO, 9,10-ANQ, and 1-NALD were the most abundant oxy-PAHs in both PM2.5 and PM1.0 at Mount Tai. The concentration of 2+3N-FLA was markedly increased compared with other species on heavily polluted days and biomass burning days, and 9N-ANT was more concentrated in measurements from days with biomass burning emissions. Secondary generation of nitro-PAHs was also more active during periods with biomass burning. The main formation pathway of nitro-PAHs during the sampling campaign was through reactions with OH radicals, but NO3 radicals also played a significant role at night. The incremental lifetime cancer risk (ILCR) was highest during periods with biomass burning, indicating that biomass burning has a significant impact on human health. By analyzing the results of back trajectory clustering under different meteorological conditions, we determined that a large area of straw burning in the North China Plain (NCP) was the dominant source of nitro and oxy-PAHs at Mount Tai during the measurement campaign.

Trace elements in PM2.5 in Shandong Province: Source identification and health risk assessment.

The chemical compositions in PM2.5 in metropolitan areas have obtained lots of attentions, of which concerns of airborne trace elements are relatively lacking. Here, PM2.5 samples were collected simultaneously in one year at four urban sites (Zibo (ZB), Zaozhuang (ZZ), Qingdao (QD) and Jinan (JN (Shandong University)), and a rural site (JN (Miaopu)) in Shandong province. 25 elements (Al, Na, Cl, Mg, Si, S, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Cd, Ba and Pb) in PM2.5 were measured by wavelength dispersive X-ray fluorescence spectrometer (WDXRF). Most trace elements (Al, Na, Cl, Mg, Si, Ca, Ti, Mn, Fe, Co, Ni, As, Se, Br, Cd, Ba and Pb) exhibited the highest levels at ZB and the lowest at QD. Meanwhile, they presented obvious seasonal variations with the highest concentrations in winter or spring and the lowest in summer. S and K were the most abundant elements in the area. In the non-crustal trace metal elements, Zn, Pb and Mn presented the highest concentrations. Positive matrix factorization (PMF) modeling revealed that secondary formation, coal combustion and industry emissions were the main sources in the region. The health risk assessments suggested that at the five sites Cd (diet) for adults, Pb and Co for children, and Mn (diet) for both adults and children (at ZB and SDU sites) had non-carcinogenic risks. As and Pb for adults and children existed carcinogenic risks, especially Pb for children. The sources of these elements with health risks were further explored. Notably, Cd, As and Pb should be paid special attention in the area due to their high concentrations in aerosol water exceeding the acceptable health risks, especially Pb.