Air pollution returns to parts of China as Covid-19 lockdowns end and people return to work
- In February, PM2.5 levels in Beijing significantly improved, with only three days of ‘very unhealthy’ air
- Air monitor calls for action around the world to prevent pollution from returning
Satellite images and air quality index (AQI) data indicate that the improvement in China's air quality as a result of recent lockdowns and industrial stoppages related to the Covid-19 pandemic may have been a temporary phase as the country gets back to work.
Nitrogen dioxide (NO2), which is produced by combustion engines and burning fossil fuels, fell in Wuhan – the early Covid-19 epicentre in China – during the 20-day period starting January 21 compared with the previous 20-day cycle, according to a coloured satellite map compiled by the European Environmental Bureau (EEB), a regional network of environmental organisations.
The Chinese authorities blocked people from leaving or entering Wuhan on January 23 and NO2 levels remained static at lower levels: below 150 micromoles per square metre (umol/m2) until late March. But during the 20-day period that ended April 9, a day after the lockdown was cancelled, levels spiked back to about 300 umol/m2 in the most polluted areas of the city, the EEB map shows.
A similar pollution curve can be seen for areas surrounding Beijing, Shanghai and Guangzhou, according to the EEB map.
In January, when the Covid-19 outbreak was just beginning, levels of the most harmful atmospheric particulate matter (known as PM2.5) were relatively higher than in the following three months. For example, during this period Beijing saw five days of PM2.5 levels between 200 and 300, deemed as very unhealthy, while only two days between 25 and 50, which indicated good air, according to aqicn.org, an AQI aggregator of various local observer and monitor sources.