As health scares like HIV/AIDS, SARS, mad cow disease and the newly feared bird flu follow hot on each other's heels, people are becoming accustomed to finding danger lurking in every corner.

But, while most threats are fairly easy to protect against, the latest danger, indoor air pollution, might prove rather harder to avoid.

With people spending around 90 percent of their time indoors, health experts are warning how dangerous this invisible threat can be, fearing it could even prove fatal for some children.

Nearly 77 percent of schools in Beijing tested in a recent survey by the China National Interior Decoration Association (CNIDA) showed high levels of deadly pollutants, such as formaldehyde, benzene and ammonia.

These chemicals, widely used in building materials and numerous household products, can cause damage to eyes, skin and nervous, respiratory and digestive systems.

The survey was carried out last month after requests from parents, according to the CNIDA's Indoor Environment Test Centre.

Centre Director Song Guangsheng said a number of primary and middle schools in Beijing had decorated their rooms during the summer holidays.

When the new semester started, parents phoned the centre, complaining that fumes at school were making their children sick. As well as dizziness, some students also developed rashes in reaction to the newly polluted environment.

Song said his centre chose 14 of the schools parents had reported and conducted indoor air quality tests.

Nearly 77 percent of the schools exceeded national standards on indoor air pollutants.

Particularly worrying, 55 percent exceeded the benchmark for formaldehyde. The figure at one school was four times higher than the national safety limit.

Tests showed the chemical pollutants mainly came from construction and decoration materials used in classrooms.

New desks and chairs were also partly to blame, Song said.

According to sources with the Beijing Municipal Education Commission, the commission has worked with government agencies, such as construction and health departments, to strengthen surveillance on indoor air pollution in schools, especially following interior renovations.

However, some schools fail to report renovation projects, and so are not subject to the required indoor air quality testing, sources said.

Liang Jinluan, a member of the Beijing Committee of the Chinese People's Political Consultative Conference, said that although there are required standards for indoor air quality, they are not always observed.

She suggested government departments take iron-handed measures to supervise indoor air quality, especially in kindergartens and primary and middle schools, as children are particularly vulnerable to toxic chemicals.

(China Daily October 27, 2005)