There are no practical tests for biological contaminants for use by non-professionals. However there are signs to watch for. You can sometimes see and smell mold colonies growing on surfaces. Mold growth should be suspected wherever there are water stains, standing water or moist surfaces. Another means of detection is by the use of ultraviolet (UV) light. Under UV light, a microorganism growth will appear luminescent. But if they are suspected in the home, an investigation should be conducted to remove and control them because of the health consequencesPrevent mold growth by keeping basements, bathrooms and other rooms clean and dry. Use a disinfectant to clean surfaces that have mold on them. If carpeting or furnishings become wet, they must be quickly and thoroughly dried or discarded.

Humidifiers, dehumidifiers and air conditioning condensing units should be regularly cleaned with a disinfectant such as chlorine bleach or safe anti-microbial.

Keep humidity at acceptable levels (less than 50 %) and make sure there’s plenty of ventilation, especially in areas where moisture tends to build up.

Vacuums with high efficiency filters or central vacuum systems can help reduce the airborne dust generated by vacuuming.

Mold spores are pollutants that are particulates–that is, they are particles so small that they “float” in the air. Larger particles settle out onto surfaces but very small particles stay suspended indefinitely.

Allergic reactions are the most common health problems associated with biological pollutants. People differ in their sensitivity to biological allergens, some may have no symptoms while sensitive persons may have severe health problems. Some common symptoms are watery eyes, runny nose and sneezing, nasal congestion, itching, coughing, wheezing and difficulty breathing, headache, dizziness and fatigue. The most severe reaction to allergens is an asthma attack, which can be life-threatening. The American Lung Association reports there are nearly 10 million people in the US with asthma. Of these, over 2.5 million are children. There are over 4,000 deaths each year from asthma. The number of persons with asthma has been consistently increasing over the last 15 years. Airborne biological pollutants present a special risk to people with allergies and asthma.

Left unchecked, mold can continue to grow and cause health problems for sensitive people. Because there are no standards for “normal” levels of mold, tests are not usually conducted. When tests are made, it is to compare types and levels of molds in the house with molds in the outside air. Mold growing on surfaces can sometimes be seen (it is sometimes invisible) and smelled (it has a musty odor). Mold should be suspected wherever there are water stains, standing water, or moist surfaces. Some conditions indicating high humidity levels are condensation on windows or walls, water pooled in the basement and crawlspace, rotting wood or other signs of water damage, use of humidifiers or un-vented kerosene and gas heaters. Damp carpet, walls feeling cold and touch, and areas where there is poor ventilation such as closets, may have mold growing on them. Cooking and bathing without using an exhaust fan promote mold growth in the kitchen and bathroom.  Firewood stored in the home can also promote mold growth.

Mold also grows in wall cavities, under carpets, behind wall coverings, above ceilings and other places where moisture can accumulate undetected. Before testing for mold, an investigation can be conducted to find building components that are damp or wet.