The Silver Lining of COVID‐19: Estimation of Short‐Term Health Impacts Due to Lockdown in the Yangtze River Delta Region, China

Abstract

The outbreak of COVID-19 in China has led to massive lockdowns in order to reduce the spread of the epidemic and control human-to-human transmission. Subsequent reductions in various anthropogenic activities have led to improved air quality during the lockdown. In this study, we apply a widely used exposure-response function to estimate the short-term health impacts associated with PM 2.5 changes over the Yangtze River Delta (YRD) region due to COVID-19 lockdown. Concentrations of PM 2.5 during lockdown period reduced by 22.9% to 54.0% compared to pre-lockdown level. Estimated PM 2.5related daily premature mortality during lockdown period is 895 (95% confidential interval: 637-1,081), which is 43.3% lower than pre-lockdown period and 46.5% lower compared with averages of 2017-2019. According to our calculation, total number of avoided premature death aassociated with PM 2.5 reduction during the lockdown is estimated to be 42.4 thousand over the YRD region, with Shanghai, Wenzhou, Suzhou (Jiangsu province), Nanjing, and Nantong being the top five cities with largest health benefits. Avoided premature mortality is mostly contributed by reduced death associated with stroke (16.9 thousand, accounting for 40.0%), ischemic heart disease (14.0 thousand, 33.2%), and chronic obstructive pulmonary disease (7.6 thousand, 18.0%). Our calculations do not support or advocate any idea that pandemics produce a positive note to community health. We simply present health benefits from air pollution improvement due to large emission reductions from lowered human and industrial activities. Our results show that continuous efforts to improve air quality are essential to protect public health, especially over city-clusters with dense population. Plain Language Summary The outbreak of COVID-19 is tragic and has caused tremendous impacts on people's life across the world. In late January 2020, massive lockdown was taken in China in order to prevent the spread of the pandemic and control human-to-human transmissions. As a result of reduced human activities, air quality was shown to improve substantially over China. A natural follow-up question would be what is the short-term health impact associated with the changes of air quality during the lockdown. This study attempted to quantify the number of avoided death due to reduced PM 2.5 concentrations over the Yangtze River Delta Region in China, a region with dense population and used to suffer from severe air pollution problems in the past.

Reduction of air pollutants and associated mortality during and after the COVID-19 lockdown in China: Impacts and implications

“…The substantial improvements in air quality since the lockdown may have brought down 51.3 thousand premature deaths and 1066.8 thousand YLLs in China, and most benefits were obtained in the four key regions. Three previous studies have estimated the health impacts from air pollution changes during COVID-19 lockdown in China ( Huang et al, 2020 ; Chen et al, 2020b ; Giani et al, 2020 ). Huang et al observed that the PM 2.5 reduction during the lockdown was associated with 42.4 thousand less premature deaths over the Yangtze River Delta region, China ( Huang et al, 2020 ).…”

“…The log-linear exposure-response function below was applied to estimate the short-term health impacts attributable to the changes in PM 2.5 and O 3 ( Huang et al, 2020 ; Liu et al, 2018 ). Where Y d denotes the daily number of deaths in each province avoided by the air quality improvement; y 0 represents the daily mean total and cause-specific (CVD and RESP) mortality rate (/100,000); β 0 is the regression coefficient derived from the RRs associated with every 1 μg/m 3 change in PM 2.5 and O 3 ; x 1 indicates daily mean air pollutant concentration in 2020; x 0 means daily mean air pollutant concentration in the same calendar in 2018–2019; Pop denotes the total population size in each province; d donates the number of days in a period.…”

“…Exposure to air pollution has estimated to cause 6.7 million excess deaths annually worldwide, and most of the access deaths were in low- and middle-income countries including China in which 1.85 million deaths were attributable to air pollution in 2019 ( D 2017 Disease and Inju, 2020 ). Although the health impacts from air pollution have been widely noticed, there have been very few studies estimating the health impacts from air pollutant reduction during and after the COVID-19 lockdown in China ( Huang et al, 2020 ; Chen et al, 2020b ; Giani et al, 2020 ). In this study, we described the changes of key air pollutants during and after the COVID-19 lockdown, and estimated the mortality burden attributable to the air pollutant reductions in China.…”

Changes of air quality and its associated health and economic burden in 31 provincial capital cities in China during COVID-19 pandemic

“…While great efforts in recent years have been made to reduce air pollution in particularly fine particulate matter (PM 2.5 ) concentration, China is still suffering relatively heavy air pollution and potentially high health risks particularly in densely populated regions ( Nie et al 2018 ; Sahu et al 2020 ; Shen et al 2017 ; Shen et al 2020 ). Haze events still occurred due to that enhanced production of secondary aerosol components might compensate the reduced primary emissions ( Chang et al 2020 ; Huang et al 2020b ; Le et al 2020 ; Sun et al 2020 ; Wang et al 2020a ), yet an overall improvement of air quality was very probably during COVID-19 period ( Bao and Zhang 2020 ; Huang et al 2020a ; Shi and Brasseur 2020 ; Xu et al 2020b ). In what extent this improvement influences the health burden, and how large is the economic cost associated with the change of air quality during COVID-19 pandemic?…”

Indoor and Outdoor Exposure to PM2.5 during COVID-19 Lockdown in Suburban Malaysia

“…The preoccupation with outdoor air pollution (Huang et al, 2020b) may have distorted our views of how exposure might have changed. This is an especially distinct period when people spent so…”