Northern China was hit by widespread sandstorms on the morning of Wednesday, March 22, 2023, impairing visibility and severely impacting breathable air for millions of people.

Sand and dust blew into central and eastern China from the Gobi Desert, which stretches across much of China’s northern border with Mongolia. Hazardous air quality was recorded by air quality monitors in multiple northeastern provinces.

The U.S. air quality index (AQI) for Beijing, China spiked to a high of 1,575 at 6 AM. Hazardous air quality levels range from 300 and up.

Hazardous air quality across northern China was measured by air quality monitors on March 22, 2023. Source: IQAir.

The wide band of hazardous air quality affected millions in some of China’s most densely populated cities. Source: IQAir.

Dust storms in China are most common in the spring and early summer (1).

Hazardous sand and dust coat cities

Air quality monitors detected hazardous air quality and elevated concentrations of particulate matter pollutants across dozens of Chinese cities.

Winds carried the sand and dust southeast of the Gobi Desert into highly populated cities. Forecasters predicted the sandstorm would weaken after being pushed further south (2).

By 8 AM PST, the most polluted cities in China were in the country’s northeastern provinces. Jining, Taian, Liaocheng, and Yanzhou were among the nation’s top ten most polluted cities in the peninsular Shandong Province southeast of Beijing. Also among the top ten were Hegang, Shuangyashan, Jiamusi, and Mudanjiang in the far northeastern Heilongjiang Province adjacent to the Russian border.

The other two cities in the top ten at that hour, Kaifeng and Jiaozuo, were bordering Shandong Province in northern Henan Province.

The ten most polluted cities in China at 8 AM on March 22 all had AQIs in the hazardous range from 1,149 to 1,891. Source: IQAir.

Hazardous air quality in those cities ranged from 1,149 to 1,891.

Air quality monitors in China detected significantly elevated concentrations of PM2.5 and PM10. Particulate matter is measured by micron diameter. PM2.5 measures 2.5 microns or less, while PM10 measures 10 microns or less. For PM10, the particles are larger and have less hazardous potential than PM2.5 because the particles have less penetration depth into critical systems in the body. The larger particles also don’t linger in the air as long as PM2.5 does. However, both pollutants are a threat to human health and are linked to coronary and respiratory disease.

While there were elevated concentrations of PM2.5 measured by air quality monitors in China, PM10 measurements were far greater. The concentration difference isn’t uncommon with sandstorms, as dust and sand particles can be found in PM10.

In Taian, the hourly average concentration of PM2.5 was 214 micrograms per cubic meter (µg/m3) at 11 AM. Meanwhile, hourly average concentration of PM10 was 1,961 µg/m3.

Hazardous air quality levels were measured in Taian. Source: IQAir.

The dust storms in China were fast moving in some cities, quickly elevating concentrations of pollutants and then subsiding as winds directed the sands elsewhere. For example, the hourly average concentration of PM2.5 in Beijing was 401 µg/m3 at 6 AM. At the same time, the hourly average concentration of PM10 was 1,677 µg/m3, the tell-tale markings of a severe sandstorm.

Hourly average concentrations of PM10 in Beijing spiked with the sandstorm’s initial onslaught but subsided later in the day. Source: IQAir.

By 1 AM, hourly average concentrations of PM10 were at 169 µg/m3 – still unhealthy, but not the extreme concentration of PM10 experienced earlier in the day.

The takeaway

The sandstorm in China is a reminder that air quality awareness is an essential component of public health. Knowing what’s in the air we breathe empowers us to act and protect ourselves.

When sandstorms strike, there are several steps one can take to protect themselves:

• Wearing a KN95/FFP2 mask with a strong seal is important to prevent sand, dust, and other pollutants from entering one’s breathing space.
• Try to stay indoors and avoid going outside.
• Avoid driving or pull over if necessary due to windy conditions and low visibility.
• Keep doors, windows, and vents closed.
• Run a room air purifier.