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

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, have pollution levels really dropped? If so, what’s the real reason behind any improvements in PM2.5?

Smart Air analyzed PM2.5 data for 11 of China’s major cities, revealing average PM2.5 levels reduced 9% year on year compared to 2019.

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


The most likely reason for this apparent success in reducing PM2.5 levels are:

  1. COVID-19 lockdowns reducing air pollution: during the lockdown, the emission of automobile exhaust gas and the suspension of the factory helped reduce PM2.5.
  2. Beijing’s continued push to lower the countries’ PM2.5 levels. For 2020, they set a year on year reduction target of 4%. The first half of the year has exceeded this target by two times.

City by City Analysis of China PM2.5 – 2019 vs. 2020 (First Half)

Breaking the data down city-by-city, only 2 cities saw an increase in PM2.5 levels compared with the same period in 2019: Shenyang and Harbin.

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


Month by Month Analysis of China PM2.5 – 2019 vs. 2020 (First Half)

Why the increase in pollution levels for Shenyang and Harbin? Analyzing the data month-by-month shows that these two cities had a very bad January and April. 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.

PM2.5 changes in 2020 of China's major cities


China’s PM2.5 – North vs South

Air Pollution Levels In The South of China


Beijing’s PM2.5 levels dropped 9% YoY.

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

Despite higher levels compared with 2020 in January and February, the huge turnaround in the following months gave Beijing an overall reduction in PM2.5.

Beijing PM2.5 level presented monthly


Shenyang saw a small increase of 1%, with January and April’s increase of 53% and 45% respectively accounting for this.

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 levels, increasing 23%.

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

And again, January and April accounted for this – PM2.5 rising 106% and 155% respectively.

Harbin PM2.5 level presented monthly

Why did Harbin and Shenyang buck the trend compared to the rest of China?

Without further analysis, it’s difficult to say for sure. However, Heilongjiang in the north-east easy is a major agricultural province. Data shows that approximately 100 million tons of straw are produced every year, with most of it going to waste. It’s possible that during the COVID-19 lockdown, crop-burning increased as it can be considered the easiest way to get rid of the straw waste.

China arable land area

Air Pollution Levels In The South of China


Shanghai PM2.5 dropped on average 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, a reversal occurred in May and June, most likely due to the increased economic activity of the ‘back to normal’ working life. Data shows that there was an increase in a travel start to travel much more than March(the passenger capacity increased 58% compared with March), either using public transportation or private car, will increasing the PM2.5.



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

Wuhan first half year PM2.5 decreased 29% in 2020

Each month has a very obvious decline. The reason is the strict lockdown from the end of January to the end of March.

Wuhan PM2.5 level presented monthly 2020

It can be seen from the figure that PM2.5 in Shanghai and Chengdu has risen in May and June. Therefore, even if everyone has back to normal life, we also need to pay more attention to air pollution!

All major cities are above WHO limit

From the picture, we can clearly see that all these 11 China’s major cities still above WHO annual standard a lot. Using Shenzhen as an example, although the air quality is the best among these 11 cities, it’s still almost 2 times more than the standard. Harbin is even 6 times more than the standard.

All China's major cities PM2.5 in 2020 are higher than WHO standard


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

China’s air pollution improved 9% during the first half of 2020 when compared to the previous year. However, out of the 11 cities analyzed two cities saw worse air pollution – both in the north-west of China.

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