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Background: Evidence remains limited about the association of maternal exposure to ambient fine particulate matter (airborne particles with an aerodynamic diameter ≤2.5 µm [PM 2.5 ]) with fetal congenital heart defects (CHDs) in highly polluted regions, and few studies have focused on preconception exposure., Methods: Using a nationwide surveillance-based case-control design in China, we examined the association between maternal exposure to PM 2.5 during periconception (defined as 3 months before conception until 3 months into pregnancy) and risk of CHD in offspring. The study included 1 434 998 births involving 7335 CHDs from 2014 through 2017 on the basis of the National Population-Based Birth Defects Surveillance System, covering 30 provinces, municipalities, or municipal districts in China. We assigned maternal PM 2.5 exposure during the periconception period to each participant using satellite-based PM 2.5 concentrations at 1-km spatial resolution. Multilevel logistic regression models were used to calculate the multivariable-adjusted odds ratio and 95% CI for CHDs in offspring associated with maternal PM 2.5 exposure, and the exposure-response association was investigated using restricted cubic spline analysis. Subgroup or sensitivity analyses were conducted to identify factors that may modify the association., Results: The average maternal exposure to PM 2.5 levels across all participants was 56.51 μg/m 3 (range, 10.95 to 182.13 μg/m 3 ). For each 10 μg/m³ increase in maternal PM 2.5 exposure, the risk of CHDs in offspring was increased by 2% (odds ratio, 1.02 [95% CI, 1.00 to 1.05]), and septal defect was the most influenced subtype (odds ratio, 1.04 [95% CI, 1.01 to 1.08]). The effect of PM 2.5 on CHD risk was more pronounced during the preconception period. Mothers <35 years of age, those living in northern China, and those living in low-income areas were more susceptible to PM 2.5 exposure than their counterparts (all P <0.05). PM 2.5 exposure showed a linear association with total CHDs or specific CHD types., Conclusions: High maternal PM 2.5 exposure, especially during the preconception period, increases risk of certain types of CHD in offspring. These findings are useful for CHD prevention and highlight the public health benefits of improving air quality in China and other highly polluted regions.

Background: Under-5 mortality rate is an important indicator in Millennium Development Goals and Sustainable Development Goals. To date, no nationally representative studies have examined the effects of fine particulate matter (PM 2.5 ) air pollution on under-5 mortality., Objective: To investigate the association of short-term exposure to PM 2.5 with under-5 mortality from total and specific causes in China., Methods: We used the national Maternal and Child Health Surveillance System to identify under-5 mortality cases during the study period of 2009 to 2019. We adopted a time-stratified case-crossover study design at the individual level to capture the effect of short-term exposure to daily PM 2.5 on under-5 mortality, using conditional logistic regression models., Results: A total of 61,464 under-5 mortality cases were included. A 10 μg/m 3 increase in concentrations of PM 2.5 on lag 0-1 d was significantly associated with a 1.15% (95%confidence interval: 0.65%, 1.65%) increase in under-5 mortality. Mortality from diarrhea, pneumonia, digestive diseases, and preterm birth were significantly associated with exposure to PM 2.5 . The effect estimates were larger for neonatal mortality (<28 days), female children, and in warm seasons. We observed steeper slopes in lower ranges (<50 μg/m 3 ) of the concentration-response curve between PM 2.5 and under-5 mortality, and positive associations remained below the 24-h PM 2.5 concentration limit recommended by WHO Air Quality Guidelines and China Air Quality Standards., Conclusions: This nationwide case-crossover study in China demonstrated that acute exposure to PM 2.5 may significantly increase the risk of under-5 mortality, with larger effects for neonates, female children, and during warm seasons. Relevant control strategies are needed to remove this roadblock to achieving under-5 mortality targets in developing countries., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Air pollution over the Yungui Plateau (YGP) in southwestern China can be caused by the transport of biomass burning aerosols from Southeast Asia; however, the magnitude and mechanisms of such long‐range transport have not been fully investigated. Here, we studied the impacts of fire emissions on vertical PM2.5 over the YGP and the transport mechanisms of PM2.5 during the fire seasons (March–April) of the neighboring Indo‐China Peninsula (ICP) region in 2015–2019 using ground‐based monitoring data, reanalysis of meteorology, and GEOS‐Chem model simulations. Average daily PM2.5 concentrations of 36.06 ± 14.86 μg m−3 were measured at 16 ground stations in the YGP with the highest value of 53.77 μg m−3 at Xishuangbanna, the nearest station to the ICP. Model simulations showed that fire emissions contributed approximately 50%–60% of the vertical PM2.5 over the YGP at a height of 3–4 km, with larger contributions in meridional than zonal cross‐sections. Four weather patterns with low pressure over the YGP were identified as favorable conditions for smoke transport. The pattern with the lowest pressure over the northern YGP and the strongest vertical wind disturbance was the most favorable for the eastward transport of fire air pollution to the YGP. Another pattern, which had the strongest southerly wind, promoted smoke aerosols to climb from eastern Myanmar and northern Laos/Vietnam to the YGP. Through these typical pathways, ICP biomass burning significantly impacted PM2.5 pollution in southwestern China. Plain Language Summary: Based on the ground atmospheric monitoring data, reanalysis of meteorological data, and simulations of chemical transport model, we studied the impacts of fire emissions on vertical PM2.5 over the Yungui Plateau (YGP) and the transport mechanisms of PM2.5 during the fire season of the neighboring Indo‐China Peninsula (ICP) region in 2015–2019. We find that fire emissions contributed approximately 50%{plus minus}20% of the vertical PM2.5 over the YGP at a height of 3–4 km, with larger contributions in meridional than zonal cross‐sections. Four weather patterns with low pressure over the YGP were identified as favorable conditions for smoke transport and the weather pattern showed two typical pathways of smoke transport from the ICP to the YGP. This study reveals the large impacts of trans‐boundary air pollution from the ICP on the air quality in the YGP during biomass burning seasons. Key Points: Average PM2.5 concentrations at Yungui Plateau (YGP) stations were 36.06 ± 14.86 μg m−3 with the highest value at the nearest station to the Indo‐China PeninsulaFire emissions contributed 50% ± 20% of the vertical PM2.5 at a height of 3–4 km over the YGPFour weather patterns with low air pressure were favorable for the transport of PM2.5 to the YGP through two typical pathways [ABSTRACT FROM AUTHOR]

The remarkable development of China has resulted in rapid urbanization (urban heat island and dry island) and severe air pollution (aerosol pollution). Previous studies demonstrate that these two factors have either suppressing or promoting effects on fog, but what are the extents of their individual and combined effects? In this study, a dense radiation fog event in eastern China in January 2017 was reproduced by the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), and the individual and combined effects of urbanization and aerosols on fog (indicated by liquid water content – LWC) are quantitatively revealed. Results show that urbanization inhibits low-level fog, delays its formation and advances its dissipation due to higher temperatures and lower saturations. In contrast, upper-level fog could be enhanced because of the updraught-induced vapour convergence. Aerosols promote fog by increasing LWC, increasing droplet concentration and decreasing droplet effective radius. Further experiments show that the current pollution level in China could still be below the critical aerosol concentration that suppresses fog. Urbanization influences fog to a larger extent than aerosols do. When urbanization and aerosol pollution are combined, the much weaker aerosol-promoting effect is counteracted by the stronger urbanization-suppressing effect on fog. Budget analysis of LWC reveals that urban development (urbanization and aerosols) alters the LWC profile and fog structure mainly by modulating condensation–evaporation process. Our results infer that urban fog will be further reduced if urbanization keeps developing and air quality keeps deteriorating in the future. [ABSTRACT FROM AUTHOR]

In January 2013, several serious haze pollution events happened in North China. Cimel sunphotometer measurements at an urban site of Beijing (Chinese Academy of Meteorological Sciences-CAMS) from 1 to 30 January 2013 were used to investigate the detailed variation of aerosol optical properties. It was found that Angstrom exponents were mostly larger than 0.80 when aerosol optical depth values are higher than 0.60 at the urban region of Beijing during January 2013. The aerosol optical depth (AOD) at the urban region of Beijing can remain steady at approximately 0.40 before haze happening and then increased sharply to more than 1.50 at 500 nm with the onset of haze, which suggests that the fine-mode AOD is a factor of 20 of the coarse-mode AOD during a serious haze pollution event. The single scattering albedo was approximately 0.90 ± 0.03 at 440, 675, 870 and 1,020 nm during the haze pollution period. The single scattering albedo at 440 nm as a function of the fine-mode fraction was relatively consistent, but it was highly variable at 675, 870 and 1,020 nm. Except on January 12 and 18, all the fine-mode particle volumes were larger than those of coarse particles, which suggests that fine particles from anthropogenic activities made up most of the haze. Aerosol type classification analysis showed that the dominant aerosol types can be classified as both 'mixed' and 'urban/industrial (U/I) and biomass burning (BB)' categories during the heavy haze period of Beijing in January of 2013. The mixed category occurrence was about 31 %, while the U/I and BB was about 69 %. [ABSTRACT FROM AUTHOR]

Background: Public health is a priority for the Chinese Government. Evidence-based decision making for health at the province level in China, which is home to a fifth of the global population, is of paramount importance. This analysis uses data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 to help inform decision making and monitor progress on health at the province level.Methods: We used the methods in GBD 2017 to analyse health patterns in the 34 province-level administrative units in China from 1990 to 2017. We estimated all-cause and cause-specific mortality, years of life lost (YLLs), years lived with disability (YLDs), disability-adjusted life-years (DALYs), summary exposure values (SEVs), and attributable risk. We compared the observed results with expected values estimated based on the Socio-demographic Index (SDI).Findings: Stroke and ischaemic heart disease were the leading causes of death and DALYs at the national level in China in 2017. Age-standardised DALYs per 100 000 population decreased by 33·1% (95% uncertainty interval [UI] 29·8 to 37·4) for stroke and increased by 4·6% (-3·3 to 10·7) for ischaemic heart disease from 1990 to 2017. Age-standardised stroke, ischaemic heart disease, lung cancer, chronic obstructive pulmonary disease, and liver cancer were the five leading causes of YLLs in 2017. Musculoskeletal disorders, mental health disorders, and sense organ diseases were the three leading causes of YLDs in 2017, and high systolic blood pressure, smoking, high-sodium diet, and ambient particulate matter pollution were among the leading four risk factors contributing to deaths and DALYs. All provinces had higher than expected DALYs per 100 000 population for liver cancer, with the observed to expected ratio ranging from 2·04 to 6·88. The all-cause age-standardised DALYs per 100 000 population were lower than expected in all provinces in 2017, and among the top 20 level 3 causes were lower than expected for ischaemic heart disease, Alzheimer's disease, headache disorder, and low back pain. The largest percentage change at the national level in age-standardised SEVs among the top ten leading risk factors was in high body-mass index (185%, 95% UI 113·1 to 247·7]), followed by ambient particulate matter pollution (88·5%, 66·4 to 116·4).Interpretation: China has made substantial progress in reducing the burden of many diseases and disabilities. Strategies targeting chronic diseases, particularly in the elderly, should be prioritised in the expanding Chinese health-care system.Funding: China National Key Research and Development Program and Bill & Melinda Gates Foundation. [ABSTRACT FROM AUTHOR]