Local news reports frequently inform Houston residents about the levels of potential allergens, such as pollen or mold spores, or of dangerous pollutants, such as ozone. The amounts of these substances are measured at special outdoor collection points. But what about indoor pollution? How do we know if the air inside our homes and businesses is safe to breathe?

There is a growing consensus among experts that indoor air can be even more polluted and potentially more harmful than outdoor air. In addition, most people spend more time inside than outside, thus increasing the risks and duration of exposure to indoor pollutants. Because they are still growing, children are even more vulnerable to the effects of poor indoor air quality than adults. Even though we usually don’t have measurements of pollutants inside our homes, we can take actions that will reduce the amounts of harmful substances in the air.

A variety of substances can cause indoor air to become unsafe. Some of these substances are chemicals that can be harmful to anyone. Examples include tobacco smoke, carbon monoxide from improperly vented heaters and fireplaces, pesticides, glues, paints and cleaners. Second-hand smoke, for example, was linked to increased risks of cancer and respiratory illnesses among non-smokers. Household chemicals such as pesticides, paint thinners or glues can cause health problems when safety instructions on the labels are not followed or if they are used in rooms that are poorly ventilated. Eliminating or restricting the use of these materials can reduce hazardous exposures.

Other indoor air pollutants only affect some people. In Houston, the damp climate and heavy rains create conditions that can be ideal for the growth of mold and mildew. Mold, that fuzzy black stuff that grows in dark, damp places, reproduces itself by releasing thousands of tiny spores. The spores allow the mold to spread and can trigger allergic reactions in some people. Since there is no way to eliminate all mold and mold spores, the best way to limit mold growth indoors is by finding and eliminating any sources of moisture near plumbing, windows or inside walls.

Damp climates also are ideal for the growth of the dust mite – another tiny organism that can cause big allergy problems. Dust mites are microscopic animals that live inside bedding, pillows and mattresses. Too small to see without a microscope, dust mites survive by eating cast off flakes of skin from the human inhabitants of the same house. Waste and pieces of body parts from dust mites are powerful allergy triggers that have also been linked to asthma in children. Dust mites can be controlled by washing bedding frequently in hot water and by replacing feather pillows and comforters with polyester bedding. Another common Houston pest, the cockroach, is also known to produce waste that can trigger allergy and asthma attacks. Cockroaches are attracted to food waste, so keeping food preparation areas clean and covering all leftovers is an easy way to begin to discourage this common insect.

Even pets can contribute to the misery of allergy sufferers. Dander, or skin and hair flakes, can be present as dust in indoor spaces and contribute to air pollution.

Sometimes, the simplest solutions – opening a window to provide fresh air, changing the filters on an air conditioning system or fixing a plumbing leak – can provide the biggest benefits when it comes to improving the quality of indoor air.

For more information on the importance of indoor air quality visit The National Institute for Environmental Health Sciences at www.niehs.nih.gov.