IF Severe Acute Respiratory Syndrome (SARS) hadn't broken out in China in 2003, people might not have given much consideration to indoor air quality.

The primary causes of indoor air quality problems are pollution sources releasing gases or particles into the air. Inadequate ventilation can increase indoor pollutant levels.

"High temperature and humidity levels can also increase concentrations of some pollutants. The latter factor is especially obvious in Shanghai with its many wet days," said Cui Lixin, an indoor environment treatment expert.

The American Environment Protection Agency lists indoor air pollution sources, including combustion sources such as oil, gas, kerosene, coal, wood and tobacco products; building materials and furnishings as diverse as deteriorated asbestos-containing insulation, wet or damp carpets, and cabinets or other furniture made of certain pressed wood products; solvents used in cleaning and hobby activities, central heating and cooling systems and humidifying devices; and outdoor sources such as radon, pesticides and outdoor air pollution.

Some sources, such as building materials, furnishings, and household products like air fresheners, release pollutants more or less continuously. If too little outdoor air enters a room, pollutants can accumulate to levels that can pose health and comfort problems.

Health hazards from indoor air pollutants may be experienced soon after exposure or years later. Immediate effects include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Symptoms of some diseases, including asthma and hypersensitivity pneumonia may also show up soon after exposure to some indoor air pollutants.

Certain immediate effects are similar to those from colds or other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution.

Other health effects may show up either years after exposure has occurred. But these effects, including some respiratory diseases, heart disease and cancer, can be debilitating or fatal.

In recent years, China has seen an increase in the number of leukemia cases among children, with building materials and furniture being blamed. "Such suspicion has not been backed by medical research or large-scale empidemiological surveys, but exposure to chemical pollutants is surely harmful," said professor Xue Huiliang, of the Hematology Department at the Shanghai Children's Medical Centre.

Environmental treatment engineers advise people not to move into a newly renovated office or apartment for two or three months. Once uncomfortable syndromes occur, professional air treatment should be sought to reduce pollutants in the air. "Putting green plants indoors will not solve air problems fundamentally," said Cui.

(Star News)