Shanghai should get colder this week with the latest in a wave of cold fronts arriving. However, the hazy sky that cast a shadow over the city at the weekend is expected to lessen over the next few days.

The latest cold front from northwestern China brought drizzle and reduced temperatures by four degrees Celsius yesterday and its effect is forecast to get stronger today and tomorrow, according to the Shanghai Meteorological Bureau.

Temperatures are expected to drop six to eight degrees during the next 48 hours and the minimum could be nine degrees tomorrow and Wednesday, the lowest this week, the bureau said.

"There will be some ups and downs in temperatures while the cold front is here," said Xu Jiye, a chief service officer of the bureau. He advised locals to be aware of the fluctuations in temperature.

Despite lower temperatures, the weather is expected to improve this week. It will be sunny with some clouds - no rain has been forecast.

With more northeast winds, the hazy sky over the weekend should brighten today, the bureau said.

"The sky will clear with the passing of the cold front and the weather should be cloudy to fine over the coming three days," said Xu.

The weather bureau also said the recent hazy and smoggy sky was not actually haze, but was caused by the dust carried in with the cold front from the north.

As a result, experts from the Shanghai Environmental Monitoring Center said the air quality this week won't improve significantly.

This month, Shanghai has experienced six polluted days, four of which occurred last week.

The environmental monitoring center reported slightly?polluted days last Monday and yesterday, medium polluted on Friday and a seriously polluted day on Saturday.

Saturday was only the second day classified as seriously polluted, the lowest in a five-level scale with one being the best, this year, the other was on March 21. The main reason is sand brought in by cold fronts from the north, which is currently experiencing a large-scale sandstorm.

As well as this, dust from construction sites, which have reopened now that the World Expo has ended, and hay burning also caused a deterioration in air quality.

"November is always the month with the poorest air quality in the city," said Wang Qian from the environmental monitoring center. "The record is 12 polluted days in November. The public should be aware of this and take health precautions."

Today is forecast to be drizzly and cloudy with temperatures ranging from a low of 11 degrees to a high of 15. The sky will be cloudy tomorrow and the temperatures should be between nine degrees low and 16 high. The air quality is forecast as good.