Almost 80 percent of office buildings in Qingdao, Shandong province, fail to meet national standards for indoor air quality, and people's health is suffering as a result, a local trade association has said.
According to a survey by the Qingdao Indoor Furnishing Industry Association, the results of which were released on Sunday, just 22 percent of the city's offices have acceptable air quality, the Peninsula Metropolitan News reported on Tuesday.
The study investigated 98 buildings over a 10-month period from January to October.
"When heating systems are running, there is a lack of proper ventilation in the offices, as windows tend to be kept closed. This leads to a buildup of pollutants in the air that can be harmful to people's health," the report said.
"In studies conducted after October, less than 10 percent of the offices met the quality standard," it said.
Most of the pollutants found in the air were volatile organic compounds, ozone and various forms of bacteria. In some instances, their levels were more than 12 times the acceptable limits, the survey said.
High levels of pollutants can cause people to experience headaches, nausea, difficulties breathing and sore throats, it said.
"I often feel dizzy when I'm at work," Yin Peiliang, who works at an office in Qingdao, said.
"My desk is near the copier room, and that makes the air quality even worse."
The office lacks a proper ventilation system, and because there is only one window in the 90-sq-m office the air has no chance to circulate, he said.
"Sometimes I have to stand by the window just to get some fresh air and stop myself feeling sick," Yin said.
According to the World Health Organization (WHO), 2.8 million people around the world, and 111,000 in China, die each year from conditions related to indoor air pollution.
The more than 300 polluting substances found in air can be linked to nearly 60 percent of all human diseases, the WHO said.
Earlier in the year, a three-month study carried out by the Guangdong environmental supervision center in Guangzhou and Shenzhen found that nearly 60 percent of indoor air pollution was caused by inadequate ventilation, Sina.com reported at the time.
Over the weekend, Song Guangsheng, head of the China Indoor Environment Treatment Supervision Center, reminded the public of the need for proper ventilation in their homes, regardless of the cold winter weather.
People should also try to limit their use of heaters to reduce the amount of air pollution, he said.
China News Services early reported that the center is working with several indoor environment management organizations to provide free air quality treatment services to 100 families in Beijing, as a precursor to a nationwide scheme.