Pollution in north China exceeds WHO guideline by 100 times; flights grounded, cars ordered off the road

Updated earlier today at 4:56am

PHOTO: A red alert for air pollution was issued in Beijing. (Reuters: China Stringer Network)

RELATED STORY: China wants 23 northern cities put on red alert for smog

MAP: China

Concentrations of airborne pollutants in a major north Chinese city have exceeded a World Health Organisation (WHO) guideline by 100 times, as northern China battled with poor air quality for the third straight day.

Key points:

• Flights grounded and highways closed
• 22 cities have issued red alerts
• Pollution alerts increasingly common in northern China

In Shijiazhuang, capital of northern Hebei province, levels of PM 2.5, fine particulate matter, soared to 1,000 micrograms per cubic metre, state-run Xinhua News Agency reported.

That compares with a WHO guideline of an annual average of no more than 10 micrograms.

In nearby Tianjin city, authorities grounded dozens of flights for the second day and closed all highways after severe smog blanketed the port city, one of more than 40 in China's northeast to issue pollution warnings.

PM 2.5 levels hit 334 micrograms per cubic metre in Tianjin, according to local environmental protection authorities.

In Beijing, PM 2.5 levels were at 212 micrograms per cubic metre.

PHOTO: Artist Liu Bolin is wearing a vest with 24 mobile phones to help him live broadcast the smog situation in Beijing. (Reuters: Jason Lee)

State media reported on Monday that more than 700 companies stopped production in Beijing, and that traffic police were restricting drivers by monitoring their license plate numbers.

Dozens of cities closed schools and took other emergency measures after a "red alert" was issued from Friday night to Wednesday, for much of northern China.

On Saturday, 22 cities issued red alerts, including top steel-making city Tangshan city in Hebei and Jinan in coal-rich Shandong province.

A red alert is the highest possible air pollution warning.

Red alerts are issued when the Air Quality Index (AQI) is forecast to exceed 200 for more than four days in succession, 300 for more than two days or 500 for at least 24 hours.

The AQI is a different measure from the PM 2.5 gauge.

Pollution alerts have become increasingly common in China's northern industrial heartland, especially during winter when energy demand, much of it met by coal, skyrockets.

AQI readings at some monitoring stations in seven cities in Hebei peaked above 400 on Monday, with Shijiazhuang and two other cities breaking above the 500 limit, Xinhua said.

Anything above 300 is considered hazardous by the US Environmental Protection Agency.

The National Meteorological Centre warned that this round of pollution is expected to affect 10 provinces, along with the municipalities of Beijing and Tianjin, hitting as far south as Jiangsu and Anhui.

Reuters/AP