Air pollution soars above safe level

The city is seen shrouded in heavy smog yesterday as the Air Quality Index hit 218 at 9am, reaching the "heavily polluted" level. — Zhang Suoqing

Air quality is set to improve in Shanghai today, following yesterday's periods of heavy pollution, environmental officials said.

Today, the city Air Quality Index (AQI )is set to be between 80 and 100 — signifying good air quality, said the Shanghai Environmental Monitoring Center.

But at 9am yesterday the AQI stood at 218, indicating heavily polluted.

The main pollutant was PM2.5, tiny particles that are especially harmful as they can get deep into the respiratory system.

The average level of PM2.5 in the city reached just over 161 micrograms per cubic meter at 10am — more than twice the national safety level of 75 micrograms per cubic meter.

Qingpu District was among the most polluted areas, with PM2.5 levels of almost 263 micrograms per cubic meter recorded.

Stronger winds in the afternoon helped disperse the smog.

In most parts of the city, the AQI then dropped below 200 to moderately polluted, although Yangpu and Hongkou districts still recorded heavily polluted.

The center said that the arrival of autumn, and with winter on the way, means that Shanghai can expect more frequent air pollution.

This week's spell of haze began on Wednesday, with the pollution coming from the north of China, said the center.

A combination of calm weather and humidity made it difficult for the smog to disperse, said officials.

Next week's air quality will depend both on local conditions and the quantity of pollutants blown down to Shanghai from the north.

Northern Chinese cities, including Beijing and Tianjin, and northern provinces such as Hebei and Shandong have been plagued by heavy pollution in recent days, with AQI levels of 500 recorded. Readings above 200 are considered to be heavily polluted.

Seasonal straw burning there is said to have added to problems caused by coal burning and vehicle exhaust fumes.

The National Meteorological Center said that the smog is set to persist in northern areas over the next few days as calm weather is forecast.