Air pollution has reached alarming levels in this capital and much of northern China, although meteorologists say strong winds in the region Wednesday night will disperse the toxic smog.

The PM 2.5 Air Quality Index exceeded 500 micrograms per cubic meter, its maximum level, in various readings Wednesday, marking a further uptick in the pollution levels affecting Beijing and China's northern region over the past week.

That index measures air particles smaller than 2.5 microns, which are considered by scientists to be harmful to human health, particularly to people's lungs.

Visibility, meanwhile, was so poor Wednesday that the upper floors of many of the city's skyscrapers could not be seen from street level.

Although public concern is still running high and many of the elderly and other citizens are choosing to remain indoors, experts from the Beijing-based China Meteorological Administration say wind gusts associated with a cold front will disperse the toxic smog starting Wednesday night.

Residents of the Chinese capital, one of the world's most polluted metropolises, have become increasingly aware of the city's severe smog problem in recent years thanks to the regular AQI readings.

The situation is particularly worrisome in winter due to low-pressure systems that trap pollutants and an increase in coal burning for heating needs.

President Xi Jinping tried Tuesday to project an image of normalcy in the capital in spite of the smog, walking down the tourist street of Nanluoguxiang with Mayor Wang Anshun and municipal Communist Party chief Guo Jinlong.

Some people praised the move on social-networking sites, pointing out that Xi and the local leaders were not wearing the anti-pollution masks that have become commonplace among the city's inhabitants. EFE