On December 31, 2019, the Chinese authorities reported to the World Health Organization (WHO) the outbreak of a new strain of coronavirus that causes a serious disease in the city of Wuhan, China. This outbreak was classified as SARS-CoV2 and is the cause of the COVID-19 disease. On March 11, 2020, the WHO declares it a Pandemic and today it is considered the greatest challenge in global health that humanity has faced since World War II and it is estimated that between 40 and 60% of the population worldwide will catch the virus. This has caused enormous challenges in countries around the world in social, economic, environmental and obviously health issues. These challenges are mainly due to the effects of the established quarantines in almost all capitals and major cities around the world, from Asia, Europe to America. However, these lockdown which began worldwide from January 23, have had a significant impact on the environment and on the air quality of cities as recently reported by NASA (National Aeronautics and Space Administration) and ESA (European Space Agency), with reductions according to them of up to 30% in some of the epicenters such as the case of Wuhan. Knowing that air pollution causes approximately 29% of lung cancer deaths, 43% of COPD deaths, and 25% of ischemic heart disease deaths, it is important to know the effects of quarantines in cities regarding air quality to take measures that favor populations and urban ecosystems when the emergency ends. Therefore, this paper describes the behavior of PM 2.5 emissions particulate matter from the 50 most polluted capital cities in the world according to the WHO, measured before-after the start of the quarantine. Likewise, the impact at the local and global level of this emissions behavior, which averaged 12% of PM 2.5 decrease in these cities. Graphical abstract Image 1 Highlights • 12% reduction in the 50 most contaminated capitals during the lockdown by COVID-19. • Dhaka, Kampala and Delhi had a PM2.5 reduction of 14%, 35% and 40%. • The greatest PM2.5 reduction within the data collected is Bogotá, Colombia with 57%. • Kubait City, presents the second largest reduction of PM2.5 (42%). • The greatest PM2.5 reductions occurred in the capitals of America, Asia and Africa. Main finding: 12% of PM 2.5 reduction in the 50 most contaminated capitals cities of the world during the lockdown by COVID-19 and a the greatest PM 2.5 reduction in a capital city was 57%.
【저자키워드】 PM2.5, Environmental pollution, capital cities, Air pollutant emissions,