World Air Quality Report Reveals Substantial Air Quality Changes In 2020 USA - English News provided by Share this article Share this article GOLDACH, Switzerland, March 16, 2021 /PRNewswire/ -- New data from IQAir's global air quality data platform, published in the 2020 World Air Quality Report and an online interactive global map, reveals the impact of COVID-19 lockdowns and behavioral changes on global particulate pollution (PM2.5) levels. Key f indings: COVID-19 impact: In 2020, 84% of all monitored countries observed air quality improvements, largely due to global measures to slow the spread of COVID-19. Air quality improvements across major cities in 2020 compared to 2019 include Beijing (-11%), Chicago (-13%), Delhi (-15%), London (-16%), Paris (-17%) and Seoul (-16%).