China’s Air Quality Improved 9% in 2020, is COVID-19 the Reason?

On paper, China’s “war” on air pollution is still underway. But with COVID-19 disrupting the first half of 2020, has air quality really improved?

Smart Air analyzed PM2.5 data for 11 of China’s major cities to get to the bottom of it. The data showed average PM2.5 reduced 9% compared to the first half of 2019.

China's major cities PM2.5 decreased 9% in 2020, air quality is getting better, due to COVID-19


Why Air Quality in China Improved in 2020

Why did China’s air quality improve in 2020? For one, the COVID-19 lockdown seemed to reduce air pollution. During the lockdown, fewer cars on the road and factory shutdowns helped reduce PM2.5.

At the same time, Beijing has continued its plan to lower the country’s PM2.5. For 2020, they set a year-on-year reduction target of 4%. The first half of the year has exceeded this target.

City-by-City Analysis of China’s 2020 Air Quality

Breaking the data down city by city, only 2 cities saw an increase in PM2.5: Shenyang and Harbin.

9/11 China's major cities PM2.5 level decreased in 2020


Ten other cities saw decreases in PM2.5. Perhaps not surprisingly, Wuhan led the way with a 29% reduction.

Month-by-Month Analysis of China’s 2020 PM2.5

How on Earth did pollution get worse in Shenyang and Harbin? Analyzing the data month-by-month suggests an answer. These two cities had a very bad January and April–pre-lockdown and post-lockdown. Despite the reduction in PM2.5 in other months, January and April pulled the average PM2.5 for these two cities above last year’s levels.

China 2020 air quality PM2.5 versus 2019


China’s PM2.5: North vs South


Beijing’s PM2.5 dropped 9% from 2019.

Beijing Pm2.5 decreased 9% in 2020 first half year

Beijing started the year poorly, with higher pollution in January and February of 2020 than 2019. But the capital then saw a huge turnaround in the following months, giving Beijing an overall reduction in PM2.5.

Beijing PM2.5 level presented monthly


Shenyang saw a small increase of 2%. This increase was due entirely to January and April.

Shenyang 2020 first half year PM2.5 increased 2%


Along with Shenyang, Harbin was the only other city in our analysis to see an increase in PM2.5. Yet this was not a small increase. Pollution soared a whopping 23%.

Harbin first half year PM2.5 increased 23% in 2020

However, this increase came entirely in January and April.

Harbin China 2020 Air Quality PM2.5 Data

Why Did Harbin and Shenyang Buck the Trend?

One reason the northeast saw increases might be straw. The northeast produces approximately 100 million tons of straw every year, most of which goes to waste. It’s possible that farmers burned more of their waste straw as while the country was on COVID-19 lockdown.

China arable land area

Air Pollution In Southern China


Shanghai PM2.5 dropped 11% year on year for the first half of 2020.

Shanghai first half year PM2.5 decreased 11%

During February – April – when the COVID-19 lockdowns were at their height – the air quality was much better compared with 2019.

Shanghai PM2.5 level presented monthly

However, Shanghai saw a reversal in May and June. This is most likely due to the increased economic activity of the “back to normal” period. Data shows that there was an increase in a travel start to travel much more than March; passenger capacity increased 58% compared with March.



Wuhan saw the biggest drop in PM2.5 of all 11 cities–29% lower than the same period in 2019.

Wuhan China 2020 air quality

Each month has a very obvious decline, but the biggest declines were January and February. These are the months Wuhan saw its strictest lockdown.

Wuhan PM2.5 level presented monthly 2020


The lockdown has helped lungs in Wuhan, which was China’s third worst in air quality the year before.

2020 Air Quality in All of China’s Major Cities Above WHO limit

Despite the improvement, 2020 air quality is above the WHO annual limit of 10 micrograms in all of China’s 11 biggest cities. Even Shenzhen–known for its supposedly clean air–still averages roughly twice the limit. Harbin averages 6 times the limit.

China 2020 air quality


Bottom Line: China's PM2.5 Levels First Half 2020

In China 2020 air quality improved 9% compared to the first half of the previous year. However, two cities in northeast China saw worse air, and all cities are far above the WHO annual limit.

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