SILC Business School, Shanghai University, Shanghai, 201800, China.
School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
Environ Pollut. 2021 Dec 1;290:117988. doi: 10.1016/j.envpol.2021.117988. Epub 2021 Aug 20.
The outbreak of coronavirus (COVID-19) has forced China to lockdown many cities and restrict transportation, industrial, and social activities. This provides a great opportunity to look at the impacts of pandemic quarantine on air quality and premature death due to exposure to air pollution. In this study, we applied the difference-in-differences (DID) model to quantify the casual impacts of COVID-19 lockdown on air quality at 278 cities across China. A widely used exposure-response function was further utilized to estimate the short-term health impacts associated with changes in PM due to lockdown. Results show that lockdown has caused drastic reduction in air pollution level in terms of all criteria pollutants except ozone. On average, concentrations of PM, PM, NO, SO and CO are estimated to drop by 14.3 μg/m, 22.2 μg/m, 17.7 μg/m, 2.9 μg/m, and 0.18 mg/m as the result of lockdown. Cities with more confirmed cases of COVID-19 are related to stronger responses in air quality, despite that similar lockdown measures were implemented by the local governments. The improvement of air quality caused by COVID-19 lockdown in northern cities is found to be smaller than that of southern cities. Avoided premature death associated with PM exposures over the 278 cities was estimated to be 50.8 thousand. Our results re-emphasize the effectiveness of emission controls on air quality and associated health impacts. The high cost of lockdown, still high level of air pollution during lockdown and smaller effects in northern cities implies that source-specific mitigation policies are needed for continuous and sustainable reduction of air pollution.
冠状病毒（COVID-19）的爆发迫使中国封锁了许多城市，限制了交通、工业和社会活动。这为研究大流行隔离对空气质量和因暴露于空气污染而导致的过早死亡的影响提供了一个绝佳的机会。在这项研究中，我们应用了双重差分（DID）模型来量化 COVID-19 封锁对中国 278 个城市空气质量的因果影响。进一步利用了广泛使用的暴露反应函数来估计与封锁导致的 PM 变化相关的短期健康影响。结果表明，封锁已导致除臭氧以外的所有污染物标准的空气污染水平急剧下降。平均而言，由于封锁，PM、PM、NO、SO 和 CO 的浓度预计分别下降 14.3μg/m、22.2μg/m、17.7μg/m、2.9μg/m 和 0.18mg/m。COVID-19 确诊病例较多的城市，尽管地方政府采取了类似的封锁措施，但空气质量的响应更强。研究发现，北方城市因 COVID-19 封锁而改善的空气质量小于南方城市。在 278 个城市中，因 PM 暴露而避免的过早死亡估计为 50800 人。我们的结果再次强调了排放控制对空气质量和相关健康影响的有效性。封锁的高成本、封锁期间仍处于较高水平的空气污染以及北方城市的影响较小，这意味着需要采取针对特定污染源的缓解政策，以持续和可持续地减少空气污染。
