The first fog of the Year of the Tiger descended upon Beijing yesterday, causing traffic delays and poor air quality.
The fog hit the city during morning rush hour, reducing visibility to less than one kilometer on the east side and leaving the scene not much better throughout the rest of the city, said Liao Xiaonong, the chief weather forecaster from the Beijing meteorological bureau.
"The atmospheric surface layer was rather humid and the humidity could not be dispersed because there was no wind, so the foggy weather will last until tomorrow's daytime," she said yesterday, adding that the forecast of fog can only be made one day in advance.
The Mirror Evening News reported that the poor visibility caused street lighting to be left on for 20 minutes longer than intended, to 6:48 am.
According to the press office at Beijing Capital International Airport, as many as 133 planes, both arrivals and departures, were delayed and nine were canceled because of the fog.
Operations at the airport returned to normal after 10 am when visibility improved to 2 km.
Traffic flow citywide was briefly hindered by the fog, with cars backed up on three expressways linking Beijing with the nearby destinations of Tianjin and Hebei.
Traffic returned to normal by around noon, the Beijing traffic management bureau said.
Visibility, rated by the BBC as "very poor," was not the only impact from the fog. Liao, from the meteorological bureau, warned that the conditions that caused the fog can also be very harmful to air quality.
"No horizontal or vertical air flow is part of the conditions that form a fog. This meteorological condition can hardly help the dispersal of pollutants," she said.
Statistics from the 28 environmental monitoring stations in the city showed the air quality yesterday was slightly polluted.
One station in Haidian district reached the standard of "heavily polluted."
The city as a whole was rated "average" by the meteorological bureau in its 2009 Beijing ecological quality evaluation.
The evaluation considers the elements of natural calamities, humidity, water resources, soil erosion and plant coverage. Compared to 2008, the entire level of ecological quality in the city was lowered by around 23 percent.