Record-Breaking Wildfires Made North American Air Worse in 2020

Source: By Laura Millan Lombrana, Bloomberg • Posted: Tuesday, March 16, 2021

Coronavirus lockdowns cleared the air in every region of the world except North America

Last year, the U.S. West suffered wildfires that charred millions of acres, left dozens of people dead and ravaged air quality from Los Angeles to Seattle.

Last year, the U.S. West suffered wildfires that charred millions of acres, left dozens of people dead and ravaged air quality from Los Angeles to Seattle. Photographer: David Odisho/Bloomberg

The devastating wildfires that torched a record 4.3 million acres in the U.S. in 2020 made North America the only region in the world where air quality was worse than during the previous year.

Most of the world’s major cities had better air last year than in 2019, mainly thanks to coronavirus lockdowns that cleared skies for weeks or months, according to the annual report by air quality platform IQAir. Though India’s New Delhi was the most-polluted capital city, its pollution levels nevertheless fell 16% from the previous year.

Los Angeles, Melbourne and Sao Paulo, all of which were close to major wildfires in 2020, were among the few where pollution was worse than in 2019.

In the U.S., 38% of cities had levels of fine particulate matter, known as PM2.5, that exceeded World Health Organization quality standards in 2020, up from 21% the previous year. Skies in the western coast were so choked with wildfire smoke during September that 77 of the world’s 100 most polluted cities that month were in the U.S.

High exposure to PM2.5, which is emitted by fossil-fuel powered vehicles, industrial activity and biomass burning, can cause asthma, lung cancer, heart disease, and has been associated with low birth weight, acute respiratory infections and strokes, IQAir said.

An increasing amount of studies are also linking worsening air pollution to increased vulnerability to Covid-19, which attacks respiratory and cardiovascular systems. Coronavirus deaths attributable to long-term air pollution exposure could represent between 7% and 33% of all fatalities due to the virus, according to an early study published in Cardiovascular Research and cited by IQAir.

The same fumes also contain greenhouse gases that are warming the planet and in turn are making wildfires more frequent and intense.

relates to Record-Breaking Wildfires Made North American Air Worse in 2020

Satellite data show the monthly average nitrogen dioxide concentrations over China in February 2019, February 2020 and February 2021. Source: ESA

IQAir’s analysis suggests that as cities tightened lockdowns last year, pollution tended to improve, and these gains were lost when movement restrictions eased. This indicates 2020’s improvements will prove fleeting without significant changes to the energy mix and to human behavior.

Chinese cities regularly rank as some of the most polluted, but last year 86% of them had cleaner air. Pollution levels are returning to pre-pandemic levels, according to satellite data published Monday by the European Space Agency.