Protection, Beijing style: face masks outsell condoms as smog gets settled in Chinese capital

Face masks are outselling condoms online as Beijingers count the hidden costs of the capital's choking smog.

Another company, Syntun, said 571,310 air purifiers were sold on the November 11 Singles Day shopping festival.

Beijing has been labouring under severe smog since the end of last month. It endured a particularly heavy five-day stretch from November 27, when the concentration of PM2.5 - tiny particles that can lodge in the lungs causing health problems including cancer - soared past officially classified levels.

Some readings during the period neared 1,000 micrograms per cubic metre - double the level of 300-500 micrograms classified as "hazardous".

After a brief respite, the smog returned over the weekend, prompting authorities to issue a red alert, the highest in a four-tier system, as well as shut schools and bring in traffic controls such as allowing cars on the roads only on alternate days.