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Social interaction anxiety has become increasingly problematic among individuals who relocate to major urban areas for work, which can adversely affect their personal health and career development, leading to severe social conflicts. We used a cross-sectional survey to explore the relationship between physical activity and social interaction anxiety, by obtaining data from 453 Beijing drifters through snowball and purposeful sampling, and used Amos 26.0 to test our hypotheses by constructing a structural equation model. Results showed that physical activity was negatively correlated with social interaction anxiety. Additionally, interpersonal competence and perceived stress mediated this relationship. Drifters who frequently engaged in sports exhibited high levels of interpersonal competence and low perceived stress, and they were less likely to experience social interaction anxiety than those who did not exercise. Countries and organizations should prioritize the health status of these individuals and provide more opportunities for them and other individuals to exercise. [ABSTRACT FROM AUTHOR]

Nitrate (NO3−) is a major contributing species to haze formation in Northern China. So far, formation processes and source apportionments of nitrate aerosols during haze pollution have not yet been well understood. In this study, the PM2.5 samples were collected in Beijing from 13 November to 24 December 2018. In addition to water‐soluble ions, oxygen (δ18O‐NO3−) and nitrogen (δ15N‐NO3−) isotopes in particulate NO3− were also determined, in order to investigate the formation pathways and potential sources of NO3− aerosols. The results showed that NO3− was a dominant species (43%) of secondary inorganic aerosols during the sampling period. The δ18O‐NO3− and δ15N‐NO3− values averaged at 83.8 ± 13.4 and 11.5 ± 5.0‰, respectively. Combining isotope compositions and Bayesian isotope mixing model, we found that heterogeneous reaction and gas phase oxidation contributed equally to nitrate formation during the sampling period. However, the contribution of heterogeneous processes to nitrate increased from 39% during the clean period to 64% during the haze period. On average, coal combustion, biomass burning, vehicle emissions, and soil emission contributed 50%, 26%, 20%, and 4%, respectively, to nitrate aerosols during the sampling period. Compared to the result in 2013, the significant decrease (~21%) of relative contribution of coal combustion to nitrate was due to strict reduction of coal consumption in Beijing. Finally, the relative contribution of traffic emissions to nitrate increased from 18% during the clean period to 30% during the haze period, suggesting that control of traffic emissions would be an important way to decrease nitrate concentrations and improve the air quality in Beijing. Key Points: Nitrate aerosols in Beijing during the haze events were mainly produced by hydrolysis of N2O5 under high humidity conditionsThe contribution of coal combustion to atmospheric nitrate decreased significantly after clean air actions implemented by Chinese governmentStrict control of traffic emissions would be an important way to decrease nitrate concentrations and improve the air quality in Beijing [ABSTRACT FROM AUTHOR]

Haze pollution occurs frequently over northern China Plain (NCP) during winter, resulting in great threats to human health. So far, limited studies have linked between emission sources and health risks from ambient field measurements. In this work, PM 2.5 samples were collected in Beijing in the 2018 winter; 23 metallic elements were determined to assess the health risks induced by PM-bound metals. During the sampling period, metallic elements constituted a minor fraction (5%) in PM 2.5 , but exhibited significant threats to human health. The cancer risk (CR) value induced by PM-bound metals was 1.41 × 10−4 for adults and 2.59 × 10−4 for children while non-cancer risk (NCR) was 2.59 for adults and 3.37 for children. Nickel (Ni), As and Cr(IV) were the major contributing elements to carcinogenic risk. Arsenic (As) contributed a major (57%) of NCR for children, and Mn (30%), Ni (27%) and As (24%) were the major contributing species to NCR for adults. Using positive matrix factorization (PMF) model, traffic-related emission (25% for children and 30% for adults) and heavy oil combustion (39% for children and 28% for adults) were the dominant sources of CR values. Moreover, the CR value induced by local emissions was higher than that by long-range transported air pollution. Local traffic emission and long-range transported heavy oil combustion enhanced CR values, threatening the human health. As results, we highlighted that control of traffic emissions and heavy oil combustion on local and regional scales should be seriously considered by the Chinese government in reduction of health risk in Beijing. Image 1 • The CR value was 1.41 × 10−4 for adults and 2.59 × 10−4 for children while NCR value was 2.59 for adults and 3.37 for children. • Traffic-related emission and heavy oil combustion were the predominant sources of CR in Beijing. • Control of local traffic emission and long-range transported heavy oil combustion is an important way to reduce health risk. [ABSTRACT FROM AUTHOR]