The capital choked in the worst smog in months on Thursday with weather forecasters warning pollution would continue to plague the city into the weekend, the Beijing Morning Post reported.
The “heavy pollution” was blamed on a trough of low pressure hanging over Beijing.
The air quality index (AQI) improved slightly from nearly 300 on Thursday to 230 on Friday, according the Beijing Municipal Bureau of Environmental Protection.
An AQI reading below 50 is good while anything over 200 is very unhealthy – and a reading of more than 300 is hazardous.
By comparison, the level in Hong Kong on Friday afternoon was 66.
The Beijing authorities warned residents to avoid strenuous outdoor activities and advised that children, the elderly and the sick should remain indoors. Many who did venture outside wore face masks to try and protect themselves.
Visibility remained low as thick smog hung over the city and the sun was obscured behind the pollution on Friday.
With persistent smog repeatedly shrouding the capital, photo apps which mask the pollution are now increasingly popular on the mainland.
Beijing has routinely suffered from serious pollution for years. Although the local authorities have been highlighting policies to try and combat the problem many residents remain to be convinced they are having much effect.
According to the Beijing Municipal Bureau of Environmental Protection, public complaints over air pollution more than doubled in the first five months of the year compared to the same period last year, the Beijing Youth Daily previous reported.
With skies over the capital often shrouded in pollution, a new smartphone app has offered at least a little cosmetic help.
Camera 360, a photo-editing app launched by Chengdu-based Pinguo, uses a series of digital filters called “Magic Sky” to banish the smog on photos.
“Magic Sky” offers seven filters to “help to turn the sky to blue”, Pinguo said on its website, noting the “severe concern caused by the increasingly serious smog”.
Users are able to choose seven different kinds of skies – “Nagrand” gives the photo a tint of blue known as cerulean, “Laputa” adds some light clouds while “Garden” adds heavy clouds.
Another photo editing app, MeituPic, has also released a new “clear fog” feature designed to sharpen pictures.
“You never need to be worried about colourless photos even when smog in Beijing is severe,” its website said.
MeituPic ranked fourth and Camera 360 number 11 on App Store’s free photo and video apps on the mainland.