Air quality and the COVID-19 outbreak in China

We appreciate that Urrutia-Pereira M., et al. have reported on “COVID-19 and air pollution:A dangerous association.”1 Research on the role of air pollution in the spread ofSARS-CoV-2 is worth discussing. Air pollution refers to harmful substances that are carriedin the air. When the quantity or proportion of the pollutants reaches or exceeds theenvironmental carrying capacity, they will change the normal state of the environment.2 With rapid economic development around the world, global pollution gradually increases.Ecological governance has become a crucial issue across the globe.3 Pollution control isalso a highly debated issue between developing countries and developed countries; Chinatoo has an environmental pollution control problem.4 China began to pay attention to the question of pollution control and its preventionmethods early on. The Chinese government has formulated many policies in thisrespect. However, these measures did not improve the environment. At the end of 2019,the COVID-19 epidemic broke in Wuhan, China.5 The Chinese government has taken aseries of measures to control the outbreak. Wuhan was locked down on January 23, 2020,and people’s travel was restricted.We downloaded the daily air pollution parameters of 367 cities around China from theChina Meteorological Administration website (http://data.cma.cn/). Records covered theperiods between January 23, 2019 and March 23, 2019;November 22, 2019 and January22, 2020;and January 23, 2020 and March 23, 2020. Pollution severity was divided intoquartiles according to the air quality index (AQI). The AQI was calculated using the concentrationof the following six pollutants: PM10, PM2.5, CO, NO2, SO2, and O3. An AQI of0–100 indicates no pollution, 101–150 indicates mild pollution, 151–200 indicates moderatepollution, and AQI >200 indicates severe pollution (USEPA 2013, http://www.Gpo.gov/).We found a significant improvement in air quality across China as a result of the reduction © 2021. Wen-tao Gan et al.