Large contributions of emission reductions and meteorological conditions to the abatement of PM_(2.5)in Beijing during the 24th Winter Olympic Games in 2022

To guarantee the blue skies for the 2022 Winter Olympics held in Beijing and Zhangjiakou from February 4 to 20,Beijing and its surrounding areas adopted a series of emission control measures.This provides an opportunity to determine the impacts of large-scale temporary control measures on the air quality in Beijing during this special period.Here,we applied the WRF-CMAQ model to quantify the contributions of emission reduction measures and meteorological conditions.Results show that meteorological conditions in 2022 decreased PM_(2.5)in Beijing by 6.9 and 11.8μg/m^(3)relative to 2021 under the scenarios with and without emission reductions,respectively.Strict emission reduction measures implemented in Beijing and seven neighboring provinces resulted in an average decrease of 13.0μg/m^(3)(-41.2%)in PM_(2.5)in Beijing.Over the entire period,local emission reductions contributed more to good air quality in Beijing than nonlocal emission reductions.Under the emission reduction scenario,local,controlled regions,other regions,and boundary conditions contributed 47.7%,42.0%,5.3%,and 5.0%to the PM_(2.5)concentrations in Beijing,respectively.The results indicate that during the cleaning period with the air masses from the northwest,the abatements of PM_(2.5)were mainly caused by local emission reductions.However,during the potential pollution period with the air masses from the east-northeast and west-southwest,the abatements of PM_(2.5)were caused by both local and nonlocal emission reductions almost equally.This implies that regional coordinated prevention and control strategies need to be arranged scientifically and rationally when heavy pollution events are forecasted.

Exposure to polycyclic aromatic hydrocarbons and risk for premature ovarian failure and reproductive hormones imbalance

Polycyclic aromatic hydrocarbons(PAHs)are a typical class of persistent organic pollutants that is ubiquitous worldwide.Previous animal studies suggested that PAHs had adverse effects on female reproduction.However,the human data regarding relationship of PAHs exposure with women reproductive health,such as ovarian dysfunction,are scarce.In this case-control study,the associations of serum levels of PAHs with the risk of premature ovarian failure(POF)and reproductive hormones in Chinese women were investigated,with recruiting 157 POF patients and 217 healthy women.The serum levels of 12 types of PAHs,as well as reproductive hormones,including follicle-stimulating hormone,luteinizing hormone and anti-mullerian hormone,were determined.In the logistic regression models,most individual PAH congeners showed significantly positive correlations with the risk of POF(p<0.05),except for fluorine and pyrene.Benzo(a)pyrene(BaP),as the most carcinogenic PAH congener,was observed to be significantly positively associated with the risk of POF.After adjustment for age,body mass index,educational levels and household income,per one-unit increase in the log-transformed BaP concentration was significantly correlated with 2.191-fold increased risk of POF(OR=2.191,95%CI:1.634-2.938,p<0.05).To the best of our knowledge,this is the first study to report an association between internal exposure levels of PAHs and the increased risk of POF in women.

包头市重灰霾特征分析及对重工业布局的启示（英文）

目的:工业排放是大气中PM2.5的重要来源,是灰霾形成的主要贡献者之一。通过分析包头市一次典型灰霾时段的污染来源及特征,研究本地工业布局在此次灰霾时段对灰霾形成的影响,并讨论城市工业布局的合理性。创新点:针对我国典型重工业城市包头市进行案例分析,研究本地城区灰霾形成的原因及重工业布局对灰霾形成的影响,并为合理布局工业提供了新的启示。方法:1.结合污染物观测数据、卫星遥感数据及后向轨迹模式的结果,揭示此次重灰霾发生时段的污染特征,找出此次重灰霾的主要来源。2.采用风向条件概率函数研究城区高浓度PM2.5与本地重工业布局间的关系。结论:1.在此次重灰霾时段,PM2.5浓度的变化趋势与其他污染物相似,说明污染主要来自人为源,且在同样发生重灰霾的情况下,PM2.5占PM10的比例较其他沿海城市低,说明粗颗粒物对包头PM10污染的贡献较其他城市大。2.结合卫星遥感数据与后向轨迹模式的结果,可以排除外来污染物的输入,并断定形成此次重灰霾的主要原因为本地人为源。3.风向条件概率函数分析结果显示本地重工业分布以及低风速的西南风(非盛行风)是造成此次重灰霾发生的主要原因。4.揭示了包头市在布局重工业或进行高强度的工业活动时不能只考虑避开盛行风,因为出现次数不多的低风速非盛行风同样会引起重灰霾的爆发;这可为包头市乃至其他工业城市在进一步调整工业布局时提供参考。