The University of Chicago reports little change in global average particulate pollution in 2020, with increases in areas such as India.

The lockdowns imposed to stop the spread of Covid led to “virtually no change” in average levels of particulate pollution worldwide during 2020, and in some of the most populous countries, pollution has increased, according to a study.

Analysis of revised satellite-derived data on PM2.5 levels, which measures tiny, dangerous particles in the air, suggests that economic lockdowns imposed in many parts of the world have brought clear skies to some areas only temporarily.

According to Air Quality of Life Index survey , based at the University of Chicago, the weighted average PM2.5 level of the global population dropped from 27.7 to just 27.5 μg/m3 between 2019 and 2020, remaining more than five times above the WHO guideline. , which was revised last year to 5 μg/m3.

Very different effects by region

Pollution levels have increased in South Asia, the world’s most polluted region, where residents are expected to lose about five years of life expectancy if conditions do not improve.

Increases have also been recorded in parts of Southeast Asia, where pollution levels have increased by up to 25% in some areas.

Christa Hasenkopf, director of AQLI, said brief periods of “blue skies” during lockdowns gave a glimpse into what the air might look like, but added: “Its relatively minor effects on the long-term quality of the air we breathe underscores that contamination It’s a persistent problem.”

Some countries have seen big declines in pollution in 2020, including Indonesia, where particulate pollution levels have dropped by more than 20% year on year due to a reduction in fire-related haze. Pollution also decreased significantly in Russia, China, Germany and Japan in 2020 compared to 2019.

Variations within countries were also observed, Hasenkopf said: “While average levels of particulate pollution in India increased by 2.9%, Delhi saw an approximately 6% decrease in particulate pollution from 2019 to 2019. 2020.”

Other populous countries where pollution levels have worsened include Bangladesh, Nigeria, Pakistan and the US.

The revision of WHO guidelines on the level of particulate pollution that people can breathe means that 97.3% of the world’s population now live in areas where PM2.5 levels are unsafe, according to the report.

Air pollution from fires

According to the AQLI analysis, permanently reducing global air pollution to meet the WHO guideline of 5 μg/m3 would add 2.2 years to average life expectancy, from about 72 to 74.2 years.

The research did not address the reasons why some areas experienced increases and decreases in pollution, Hasenkopf said, but cited possible causes: forest fires”.

The haze caused by thousands of fires on the Indonesian island of Sumatra and Borneo had a drastic impact on air quality in 2019. In 2020, pollution in Singapore and Indonesia dropped by 38.3% and 20.3%, respectively.

Elsewhere in Southeast Asia, however, PM2.5 has increased, including in Cambodia (25.9%) and Thailand (10.8%), with researchers pointing to biomass fires, forests and peatlands, emission patterns of loose fuel and coal power plants. as the main factors of contamination.

By Rebekah Ratcliffe. Article in English


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