As pollution has darkened the skies above Northern China since Wednesday, Beijing issued a blue alert on Thursday. And forecasts say the heavy smog won't be dispersed by cold weather till next Monday.

According to the national meteorological center, this round of air pollution blankets a number of provinces in northern China, to include: Beijing, Liaoning, and Shandong. The concentration of hazardous PM2.5 particles, exceeded 300 micrograms per cubic meter on Friday, indicating severe pollution hovering over the capital. In an effort to endure this particularly heavy five-day stretch, people in Beijing are again wearing masks to protect themselves. These surgical masks have almost become a trend in China and can be seen around all corners of the streets.

The bad air days in Beijing are getting people anxious and worried about going outdoors, especially mothers with children.

"We can feel that the smog is serious. At the moment, my whole family is coughing due to the smog, and the kid dares not to go outside to play, and every day (we) have to turn the air purifier up to the highest setting. Probably that will help."

It sounds like air purifiers are the last straw for many desperate families. Syntun, a statistics company, said nearly 600-thousand air purifiers were sold on the November 11 Singles Day shopping festival last year.

Speaking of air purifiers, The Smog Free Tower, the world's largest air purifier was recently opened to the public in Beijing. The seven-meter-high tower, created by Dutch artist and innovator Daan Roosegaarde and his team, inhales dirty air and release bubbles of smog-free air.

"So the Smog Free Project is about the Smog Free Tower providing clean air, but it's also about the Smog Free Ring creating an engagement and making the people in China part of the solution, instead of just feeling part of the problem," said Dutch artist and innovator Daan Roosegaarde.
 
China has implemented a series of measures to curb air pollution. From now until 2020, China aims to cut coal output by 500 million tonnes, or about 19 percent of its current annual output. It also plans to reduce emissions of major pollutants in the power sector by 60 percent.

It is expected that North China will face more bouts of smog in autumn and winter, given unfavorable weather conditions this year. Experts advise the public to take precautions and reduce outdoor activities.