Outdoor air pollution in cities is a major health problem. Much effort and money continue to be spent cleaning up pollution in the outdoor air. But air pollution can be a problem where you least expect it, in the place you may have thought was safest -- your home. Many ordinary activities, such as cooking, heating, cooling, cleaning and redecorating, can cause the release and spread of indoor pollutants at home. Studies have shown that the air in our homes can be even more polluted than outdoor air. Many Americans spend up to 90% of their time indoors, often at home. Therefore, breathing clean indoor air can have an important impact on health. People who are inside a great deal may be at greater risk of developing health problems, or having problems made worse by indoor air pollutants. These people include infants, young children, the elderly and those with chronic illnesses. Many factors determine whether pollutants in your home will affect your health. They include the presence, use and condition of pollutant sources, the level of pollutants both indoors and out, the amount of ventilation in your home, and your overall health.
What are Biological Pollutants?
Biological pollutants are or were living organisms. They promote poor indoor air quality and may be a major cause of days lost from work and school, and of doctor and hospital visits. Some can even damage surfaces inside and outside your house. Biological pollutants can travel through the air and are often invisible. Some common indoor biological pollutants are:
animal dander (minute scales from hair, feathers, or skin);
dust mite and cockroach parts;
infectious agents (bacteria and viruses); and
Some of these substances are in every home. It is impossible to get rid of them all. Even a spotless home may permit the growth of biological pollutants. Two conditions are essential to support biological growth: nutrients and moisture. These conditions can be found in many locations, such as bathrooms, damp or flooded basements, wet appliances (such as humidifiers and air conditioners), and even some carpets and furniture. Modern materials and construction techniques may reduce the amount of outside air brought into buildings, which may result in high moisture levels inside. Using humidifiers, unvented heaters, and air conditioners in our homes has increased the chances of moisture forming on interior surfaces. This encourages the growth of certain biological pollutants.
The Scope of the Problem
Most information about sources and health effects of biological pollutants is based on studies of large office buildings and surveys of homes in the northern U.S. and Canada. These surveys show that 30% to 50% of all structures have damp conditions which may encourage the growth and buildup of biological pollutants. This percentage is likely to be higher in warm, moist climates. Some diseases and illnesses have been linked with biological pollutants in the indoor environment. However, many of them also have causes unrelated to the indoor environment. Therefore, we do not know how many health problems relate only to poor indoor air.
Health Effects of Biological Pollutants
All of us are exposed to biological pollutants. However, the effects on our health depend on the type and amount of biological pollution and the individual person. Some people do not experience health reactions from certain biological pollutants, while others may experience one or more of the following reactions:
Except for the spread of infections indoors, allergic reactions may be the most common health problem with indoor air quality in homes. They are often connected with animal dander (mostly from cats and dogs), with house dust mites (microscopic animals living in household dust), and with pollen. Allergic reactions can range from mildly uncomfortable to life-threatening, as in a severe asthma attack. Some common signs and symptoms are:
Health experts are especially concerned about people with asthma. These people have very sensitive airways that can react to various irritants, making breathing difficult. The number of people who have asthma has greatly increased in recent years. The number of people with asthma has gone up by 59% since 1970, to a total of 9.6 million people. Asthma in children under 15 years of age has increased 41% in the same period, to a total of 2.6 million children. The number of deaths from asthma is up by 68% since 1979, to a total of almost 4,400 deaths per year.
Talking to Your Doctor
Are you concerned about the effects on your health that may be related to biological pollutants in your home? Before you discuss your concerns with your doctor, you should know the answers to the following questions. This information can help the doctor determine whether your health problems may be related to biological pollution.