Sandstorm skews capital's air quality figures for May

A sandstorm in early May resulted in the Beijing-Tianjin-Hebei region's average air quality taking a hit, with the number of “good air” days reduced by 23.5 percent year-on-year, the Ministry of Environmental Protection said on Friday.

Air quality was defined as good on just 39 percent of days in the region's 13 cities last month, a 23.5 percent year-on-year decrease, said Liu Zhiquan, head of the ministry's environmental monitoring department.

In addition, PM10 concentrations soared by 59.4 percent year-on-year to reach 153 micrograms per cubic meter, the ministry said.

PM2.5 concentrations also increased by 14.9 percent year-on-year, it added.

PM10 and PM2.5 refer to microscopic particulate matter that are air pollutants hazardous to human health. Both are major measures of air quality.

The ministry attributed the dramatic drop in air quality in the Beijing-Tianjin-Hebei region to a sweeping sandstorm in early May.

For three days from May 3, the sandstorm blanketed China's northern and northwestern regions including Beijing, Tianjin and many other cities, sending concentrations of PM10 — the main pollutant in the dust — soaring to up to 1,000 micrograms per cubic meter, data released by the China National Environmental Monitoring Center showed.

The dust then moved southward, affecting a larger region that stretched as far as Shanghai, according to the ministry's statement, adding that it covered 1.63 million square kilometers in total, or more than 16 percent of China.

In addition to the worsening air pollution in northern cities, the 338 cities under regular monitoring by the ministry nationwide also witnessed a drop in air quality in May.

Liu said these cities experienced 70.5 percent of “good air” days on average during the month, a 12.4 year-on-year decrease, while PM10 concentrations also increased.