Southeast Asia had a 40% reduction in toxic airborne particles caused by transportation and energy production in 2020, according to the World Meteorological Organization’s (WMO) Air Quality and Climate Bulletin.
During the first year of the pandemic, China, Europe, and North America saw reductions in emissions and improved air quality, while countries like Sweden saw less dramatic improvements due to existing air quality containing comparatively lower microparticle levels (PM2.5) of harmful sulphur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), and ozone (O3).
Although the clean air development was welcomed by many people with breathing problems, the absence of harmful microparticles cleared the way for naturally occurring ozone, which is “one of the most dangerous pollutants,” according to Dr. Oksana Tarasova, chief of the WMO’s Atmospheric Environment Research Division.
Despite such an unexpected experiment with atmospheric chemistry, it has been noted that air quality in many places of the world would not satisfy WHO requirements even if transportation and other emissions were reduced.
Despite the fact that human-caused air pollution emissions decreased as a result of COVID-19 movement restrictions and the ensuing global economic downturn, weather extremes fueled by climate and environmental change triggered unprecedented sand storms, including the “Godzilla” dust cloud in June 2020 – the largest African dust storm on record – and wildfires from Australia to Siberia, worsening air quality.
This trend is expected to continue in 2021 according to WMO, citing destructive wildfires in North America, Europe, and the Russian tundra, which have “damaged air quality for millions,” as well as sand and dust storms that have blanketed several regions and crossed continents.
Air pollution has a substantial influence on human health, according to the UN agency. According to the latest Global Burden of Disease assessment, global mortality increased from 2.3 million in 1990 (91 percent due to particulate matter, 9% due to ozone) to 4.5 million in 2019 (92 percent due to particulate matter, 8% due to ozone).
The WMO’s first Air Quality and Climate Bulletin is based on data from over 540 observation stations in and around 63 cities in 25 nations, spanning the world’s seven geographical regions.
In comparison to the same periods in 2015–2019, the analysis revealed a 30–40% reduction in total PM2.5 concentrations during the full lockdown in 2020.
However, even within the same region, PM2.5 levels demonstrated complex behavior, with increases in some Spanish cities, for example, ascribed mostly to the long-range movement of African dust and/or biomass burning.
Ozone concentrations vary widely among locations, ranging from no change to minor increases (as in Europe) and bigger increases (as in the United States) (up 25% in East Asia and up 30% in South America).
According to the WMO’s Bulletin, sulphur dioxide concentrations were 25–60% lower in 2020 than they were in 2015–2019 for all regions. Carbon monoxide levels were reduced in all regions, with South America experiencing the greatest reduction, up to 40%.
Despite the fact that intense wildfires caused “anomalously high” microparticle pollution in several parts of the world in 2020, the World Meteorological Organization (WMO) explained that forest fires in southwestern Australia in December 2018 and January 2019 “also led to temporary cooling across the southern hemisphere, comparable to that caused by ash from a volcanic eruption”.