Year's worst smog to hit north China; second red alert likely

Beijing and parts of northern China will see the worst smog so far this year from Saturday which may prompt authorities to issue a second red alert this month.
China's National Meteorological Centre said, the air pollution will last through the following Tuesday and be worse than the spell between December 6 and 9, which forced Beijing to issue its highest first-ever smog alert since the emergency response system was created in October 2013.
Visibility in Beijing and some neighbouring regions will be reduced to less than one km during the new bout of smog, and the density of PM 2.5 pollution in some of the regions will exceed 500 micrograms per cubic meter, state-run Xinhua news agency quoted the observatory as saying.

The December 6 smog recorded PM 2.5 around 400 micrograms per cubic meters. Beijingers expects a second record as the weekend smog expected to cross that.
On December 7, Beijing issued the first-ever red alert as the city of over 22 million people faced the worst ever smog, forcing authorities to shut down schools and putting restrictions on factories and traffic.
The World Health Organisation's recommended maximum is 25 micrograms per cubic meter.
Coal burning and car emissions are some of the major sources of air pollution.
In winter, an increase in coal-burning for heating in north China and still weather often exacerbate other forms of pollution and create periods of heavy smog lasting days.