Testing services for indoor air pollutants will be available free for Shanghai residents to help them circumvent health hazards and promote green living concepts.

Residents can apply for the service by contacting the Shanghai Environmental Protection Industry Association, and families with children, the elderly and those suffering from blood diseases will be prioritized, said Li Wei, deputy secretary general of the association.

The measurement of PM2.5 was included as an indicator of the country's air quality standards in February in response to widespread public concern.

PM2.5 - tiny particles smaller than 2.5 micrometers in diameter - can be easily absorbed into the lungs and can trigger severe cardiovascular and respiratory disorders.

People associate the pollution with factory chimneys and vehicle exhaust, said Li, but they rarely know that some indoor sources, such as kitchen smoke and cigarettes, also produce the pollutant.

Testing organizations and businesses in the association will provide the test service and absorb the costs, according to Li, and the association will also gather statistical data while providing the service.

This is the sixth year in which they have monitored indoor pollution for residents, but it is the first time PM2.5 has been included.

More than 13,000 households have benefited from the free service in the past five years, figures from the association showed.

"I make dinner for my family every day and so I'm exposed," said Hu Xiulan, a 68-year-old retired teacher.

"I'm eager to know if my indoor environment is healthy."

Hu, a breast cancer patient, believes her disease is related to the fact that her apartment was painted and decorated three years ago.

"So I must be very cautious about the safety of my surroundings, and I'm interested in anything I can try to make improvements."

Experts suggested ventilating rooms and opening windows after a rainfall when the air is clean outdoors.

Qian Hua, director of the research institute of atmospheric environment under the Shanghai Academy of Environmental Sciences, said it was also important to have proper air filters.

Feng Yongfeng, founder of Green Beagle, a Beijing-based non-governmental organization, initiated an online appeal in 2011 calling for people to monitor the concentration of PM2.5 themselves, and some donated money to the organization to help it purchase the testing devices.

Testing work indoors and outdoors is going on in a number of cities, including Shanghai, Guangzhou, Wuhan, Wenzhou and Shenzhen, Feng said.