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The Bohai Sea (BS) region, an area of China that is severely polluted with atmospheric polycyclic aromatic hydrocarbons (PAHs), has received wide attention in recent decades. To characterize the variations of the concentrations and sources of PAHs from June 2014 to May 2019, 15 PAH congeners (Σ15PAHs) were measured in atmospheric samples (N = 228) collected at 12 sites around the BS, and the health risk and direct medical costs associated with lung cancer caused by exposure to PAHs were also estimated. The annual daily average concentration of Σ15PAHs was 56.78 ± 4.75 ngm-3 , which was dominated by low molecular weight PAHs (LMW-PAHs) containing three rings (58.7 ± 7.8 %). During the 5-year sampling period, the atmospheric Σ15PAHs concentration reduced by 17.5 % for the whole BS region, with an especially large drop of 51.7 % observed in the tightly controlled area of Tianjin (TJ), which was mainly due to a decrease in the concentration of high molecular weight PAHs (HMW-PAHs) containing five or six rings. Generally, the concentration of Σ15PAHs was highest in winter and lowest in summer, which can mainly be attributed to the change in LMW-PAH concentration. Based on the positive matrix factorization (PMF) model, PAHs in the BS region were mainly ascribed to coal combustion and biomass burning. The PAH contributions of coal combustion and motor vehicles showed different trends for the BS region (PAHs from coal combustion rose by 7.2 % and PAHs from motor vehicles fell by 22.4 %) and for TJ (PAHs from coal combustion fell by 12.6 % and PAHs from motor vehicles rose by 6.9 %). The incidence of lung cancer (ILCR) caused by exposure to atmospheric PAHs decreased by 74.1 % and 91.6 % from 2014 to 2018 in the BS region and in TJ, respectively. This was mainly due to the decrease in the concentration of highly toxic HMW-PAHs and was reflected in USD 10.7 million of savings in direct medical costs of lung cancer caused by exposure to PAHs, which represent a decrease of 46.1 % compared to the corresponding costs before air pollution prevention and control was implemented around the BS. There was an even higher reduction in medical costs of 54.5 % in TJ. Hence, this study proves that implementing pollution prevention and control not only effectively reduced the concentration of pollutants and the risks caused by them, but it also significantly reduced the medical costs of diseases caused by the corresponding exposure. [ABSTRACT FROM AUTHOR]

The Bohai Sea (BS) as the most polluted area of PAHs in China has been received wide attention in recent decades. To characterize the variations of concentrations and sources of PAHs from June 2014 to May 2019, fifteen congeners of PAHs (∑15PAHs) were measured from atmospheric samples (N=228) collected at 12 sites around the BS, and health risk and direct medical costs associated with lung cancer exposed to PAHs were also estimated. The annual daily average concentration of ∑15PAHs was 56.8 ± 4.7 ng m-3, dominated by low molecular weight (LMW-PAHs, 3-ring) (58.9 ± 7.8 %). During the five-year sampling period, the atmospheric ∑15PAHs concentration reduced by 17.5 % for the whole BS, especially in the tightly controlled area of Tianjin (TJ) with a drop of 51.7 %, which was mainly due to the decrease of high molec-ular weight PAHs (HMW-PAHs, 5-6 ring) concentration. Generally, the concentration of ∑15PAHs was highest in winter and lowest in summer, mainly attributed to the change of LMW-PAHs concentration. Based on PMF model, PAHs at the BS were mainly ascribed to coal combustion and biomass burning. And the contribution of coal combustion and motor vehicle to PAHs had a different performance between the BS (coal combustion rose by 6.7 %, motor vehi-cle fell by 22.7 %) and TJ (coal combustion fell by 13.2 %, motor vehicle rose by 6.7 %). The in-cidence of lung cancer (ILCR) caused by exposing to atmospheric PAHs at the BS and TJ de-creased by 74.1 % and 91.6 % from 2014 to 2018, respectively. That was mainly due to the de-crease of the concentration of highly toxic HMW-PAHs. It was reflected on the savings of $10.7 million in direct medical costs of lung cancer exposed PAHs, which was accounted 46.1 % before air prevention and control around the BS. And there was a higher cost reduction of 54.5 % in TJ. Hence, this study proved that implementing pollution prevention and control not only effective-ly reduced the concentration of pollutants and the caused risks, but also significantly reduced the medical costs of diseases caused by corresponding expose. [ABSTRACT FROM AUTHOR]

[Display omitted] • BS atmospheric Σ 10 OPEs level was 7.65 ± 6.42 ng m−3 with rising trend in 2014–2019. • volatilization of TCEP and TCPP from seawater dominated atmospheric concentrations. • volatilization of TCEP and TCPP deriving from coastal seawater accounting for 73% • river input was the main source of TCEP and TCPP for the BS seawater. Organophosphate esters (OPEs) are still produced and used in large quantities in the world-wide, and the environmental burden and behavior have generated widespread concern, especially in some large-scale waterbodies. This study conducted a comprehensive assessment on the temporal and spatial variabilities and budget of OPEs to trace the source for the Bohai Sea (BS), based on a 5-year seasonal monitoring campaign (June 2014 to May 2019) of 12 atmospheric sites around the BS and our previous studies. The average concentration of Σ 10 OPEs in atmosphere during the sampling period was 7.65 ± 6.42 ng m−3, and chlorinated OPEs were the major compounds. The Seasonal-Trend decomposition procedure based on Loess (STL) analyzed that during the 5-year sampling period, the atmospheric concentrations of Σ 10 OPEs had a slightly increasing trend with a rate of + 0.092 ng m−3 yr−1, and the seasonal concentrations had a distinct seasonal distribution. The highest concentration of Σ 10 OPEs was observed at the sampling site of Dalian, followed by Tianjin, Yantai, and Beihuangcheng. The estimation of the fugacity ratios and air–water gas exchange fluxes established that the concentration levels of two major components of chlorinated OPEs (tris-(2-chloroethyl) phosphate (TCEP) and tris-(1-chloro-2-propyl) phosphate (TCPP)) in the atmosphere were dominated by their volatilization from BS's seawater (1.24 ± 0.46 t yr−1 for TCEP and 5.15 ± 2.15 t yr−1 for TCPP), with 73% deriving from the coastal seawater. The budget assessment suggested that the volatile fluxes of TCEP and TCPP accounted for 8% and 29% of their storages (15.6 ± 5.32 t for TCEP and 17.6 ± 6.70 t for TCPP) in the BS seawater, which were mainly contributed by continental river input (20% for TCEP and 42% for TCPP). The efforts indicated that river inputs of TCEP and TCPP needed to be paid more attention for the improvement of environmental quality of the BS. [ABSTRACT FROM AUTHOR]