Shanghai's air quality improved somewhat yesterday after two days of the worst pollution on record, the Shanghai Environmental Protection Bureau said.

Despite the improvement, the bureau said the air was still moderately polluted, which is level four on the five-tier scale.

The bureau said air quality is expected to improve further today to level 3 or slightly polluted. Tomorrow the air quality will be good, or level 2, the bureau said

The Shanghai Meteorological Bureau also said yesterday that the sky will clear up in the next few days as the wind will be blowing from the sea.

"A southeastern wind is expected to bring clean air to the city tomorrow," said Wu Rui, a chief service officer of the bureau. "The source of the wind is clean and it should help diffuse the dust in the air."

Moreover, rain is forecast on the weekend, which should also help clear the air, Wu told Shanghai Daily yesterday.

Temperatures in the next few days should increase gradually, the bureau said.

Shanghai had a slightly polluted day on Sunday. Two severely polluted days followed. Shanghai was the dirtiest city in the nation on both days due to particle matters in the air.

Environmental protection officials said they didn't properly prepare for the impact of the sandstorm in the country's north and failed to inform the public about possible poor air quality.

The bureau said they will work with education authorities to warn students of the dangers of outdoor exercise on highly polluted days. They will also send short message warnings in future about poor air quality.

Today's forecast calls for clouds with a low of 16 degrees Celsius and a high of 23 degrees, the bureau said.

Tomorrow should also be cloudy with temperatures ranging from 17 to 26 degrees, the bureau said.