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Air pollution exposures are increasingly suspected to influence the development of childhood adiposity, especially focusing on outdoor exposure, but few studies investigated indoor exposure and childhood obesity. We aimed to examine the association between exposure to multiple indoor air pollutants and childhood obesity in Chinese schoolchildren. In 2019, we recruited 6499 children aged 6–12 years from five Chinese elementary schools in Guangzhou, China. We measured age-sex-specific body mass index z score (z-BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) on standard procedures. Four different indoor air pollution (IAP) exposures, including cooking oil fumes (COFs), home decoration, secondhand smoke (SHS), and incense burning, were collected by questionnaire and then converted into an IAP exposure index with four categories. Association between indoor air pollutants and childhood overweight/obesity as well as four obese anthropometric indices were assessed by logistic regression models and multivariable linear regression models, respectively. Children exposed to ≥3 types of indoor air pollutants had higher z-BMI (coefficient [β]:0.142, 95% confidence interval [CI]:0.011–0.274) and higher risk of overweight/obesity (odd ratio [OR]:1.27, 95%CI:1.01–1.60). And a dose-response relationship was discovered between the IAP exposure index and z-BMI as well as overweight/obesity (p for trend <0.05). We also found that exposure to SHS and COFs was positively associated with z-BMI and overweight/obesity (p < 0.05). Moreover, there was a significant interaction between SHS exposure and COFs on the higher risk of overweight/obesity among schoolchildren. Boys appear more susceptible to multiple indoor air pollutants than girls. Indoor air pollution exposures were positively associated with higher obese anthropometric indices and increased odds of overweight/obesity in Chinese schoolchildren. More well-designed cohort studies are needed to verify our results. • A total of 6753 schoolchildren aged 6–12 years from Guangzhou, China was included. • Multiple indoor air pollution exposures were positively associated with childhood obesity and obese anthropometric indices. • Secondhand smoke exposure interacts withcooking oil fumes exposure in association with childhood overweight/obesity. • Multiple indoor air pollution exposures for boys have higher z-BMI. [ABSTRACT FROM AUTHOR]

Previous studies have indicated that exposure to green space may benefit human health. However, the available evidence concerning the effects of greenness, especially school-based greenness, on pediatric obesity is scarce. To explore the association between school-based greenness and adiposity in children and adolescents in China. We conducted a nationwide cross-sectional study of 56,620 children and adolescents (aged 6–18 years) in seven provinces/municipalities across China. School-based greenness was assessed using satellite-derived Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) within 100-, 500-, and 1000-m circular buffers around each school's address. Generalized linear mixed regression models were used to estimate associations of greenness with BMI z-scores (zBMI), waist circumference, and prevalent overweight/obesity. We also explored the potential mediating role of ambient air pollution and physical activity in the greenness-adiposity associations. In the adjusted model, an IQR increase in NDVI -1000m was associated with lower zBMI (β: -0.11, 95% confidence interval[CI]: -0.13,-0.09) and waist circumference (β: -0.64, 95%CI: -0.78,-0.50). Consistently, an IQR increase in NDVI -100m , NDVI -500m , NDVI -1000m was associated with 7–20% lower odds of overweight/obesity in the adjusted models. Air pollutants mediated 6.5–29.1% of the association between greenness and zBMI. No significant mediation effect was observed for physical activity. Higher school-based greenness levels were associated with lower zBMI, waist circumference, and lower odds of overweight and obesity in children and adolescents. Ambient air pollutants may partially mediate the greenness-adiposity associations. Image 1 • This study was conducted in 56,620 Chinese schoolchildren aged 6–18 years. • School-based greenness was negatively associated with pediatric obesity. • PM 2.5 may partially medicated the association between greenness and pediatric obesity. [ABSTRACT FROM AUTHOR]

Carbon policies are important not only for mitigating global climate change, but also for controlling local and regional air pollution. The large regional disparities in economic development and air pollution across China calls for regionally differentiated policies. Previous studies have not systematically investigated the environmental impacts of regional carbon policies in China covering different spatial scales. This study constructs a multi-regional dynamic computable general equilibrium (CGE) model covering 30 provinces of China to assess the impacts of national and subnational carbon polices on CO 2 emissions and co-emitted air pollutants from 2020 to 2050. We consider one national carbon policy which aims to achieve China's 2030 national CO 2 abatement target, as well as three regional policies with the same policy stringency as the national one but only applied to eastern China (EP), the Jiangsu-Shanghai-Zhejiang area (JSZP), and the Beijing-Tianjin-Hebei area (BTHP), respectively. We find that regional policies (EP, JSZP, and BTHP) are as effective in reducing CO 2 emissions in their targeted regions as the national policy. However, they lead to an increase in CO 2 emissions in untargeted regions (the so-called "emissions leakage"). The CO 2 leakage rates, which depend on the policy spatial coverage, are 4%, 13%, and 65% for EP, JSZP, and BTHP, respectively, in 2050. Compared with CO 2 , changes in air pollutant emissions, including sulfur dioxide (SO 2), nitrogen oxides (NO x), volatile organic compounds (VOC), and fine particulate matter (PM 2.5), exhibit a similar pattern under all policy scenarios, but the magnitude of change is significantly smaller. Transportation, thermal power, and some energy intensive industries are the three largest contributors to CO 2 and air pollutant emission reductions. Our results suggest that regional carbon policy is effective in reducing CO 2 and air pollutant emissions in the targeted regions, and extending the spatial coverage or increasing policy stringency can largely inhibit emissions leakage. • We examine effects of subnational carbon policies on CO 2 and co-emitted pollutants. • A multi-regional dynamic CGE model covering China's 30 provinces is constructed. • Subnational policies are as effective in their targeted regions as the national one. • Subnational policies lead to emission leakage to untargeted regions. • Extending spatial coverage or increasing policy stringency inhibits emission leakage. [ABSTRACT FROM AUTHOR]