After a big improvement in 2018, new data shows China’s war on air pollution is slowing down. A Smart Air analysis of 2019 PM2.5 data for China’s 15 largest cities found that more than half saw worse air quality over 2018.

Maps comparing average PM2.5 in December 2018 to December 2019 show a general increase in PM2.5 across the country, especially in southern China.

Source: www.aqistudy.cn

These Cities Saw Cleaner Air

Beijing

Beijing’s PM2.5 have dropped by 10.7% in 2019, reaching half of what it was back in 2014.

Beijing’s improvement suggests that the 2013-2017 Clean Air Action Plan has had an effect. However, the improvement seems to go even farther back, since data stretching back to 1998 shows improvement even in the decade before the action plan.

However, Beijing’s progress is slowing down. Beijing cut 16 micrograms in 2017, 10 micrograms in 2018, and just 5 micrograms in 2019. This could be a sign that the easiest fixes have already been made and that the remaining fixes may be harder to execute.

 Guangzhou

Guangzhou saw an 8.8% decrease in 2019.

One of China’s most important automobile manufacturing hubs, Guangzhou has moved to make cars on its streets greener. By 2020, the city plans to replace all gasoline-fueled buses with pure electric buses and encourage more electric vehicles by lowering purchase and maintenance prices, as well as increase charging stations.

These Cities Saw Worse Air

Xi’an

Despite recent efforts, Xi’an PM2.5 was up 9.7% in 2019.

One potential reason is insufficient gas supply infrastructure, making Xi’an still heavily reliant on coal. However, there is hope: if Xi’an achieves its goal to go coal-free by 2020, its PM2.5 should come down.

In addition, Shenyang, Tianjin, Chongqing, and Harbin all saw worse air in 2019.

All Major Chinese Cities Above WHO Limit

Despite the range of improvement and worsening air, all cities have this in common—they are all above the WHO annual limit. Even the cleanest city, Shenzhen, averages more than double the limit.

This fact carries consequences for people’s health, since studies show that PM2.5 raises blood pressure, inflammation, and rates of heart attacks and strokes. This is true even at low levels around 10 micrograms.

WATCH: The Harmful Health Effects of PM2.5

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While Particulate Improves, Ozone Worsens

This analysis used over 33,000 PM2.5 data points pulled from official sensors around the country. However, it does not include gas pollutants like ozone, which have been rising in Beijing. Paradoxically, improving particulate pollution can actually make ozone worse.

Studies Document Protective Effects of Purifiers, Masks

Despite the harms of PM2.5, studies have found that wearing masks prevents effects on blood pressure and heart rate variability. Placebo-controlled studies of air purifiers have found that reducing particulate in the home prevents harm to blood pressure, inflammation, and immune response—even among young, healthy twenty-year-olds.

Smart Air is a certified B Corp committed to combating the myths big companies use to artificially inflate the price of clean air. To help people living in polluted cities protect themselves, Smart Air provides empirically backed, no-nonsense purifiers and masks, helping to lower the cost of clean air.