Controlling air quality in homes and facilities is critical. What are the specific types of contamination and what are the associated challenges and risks?
What's normal?
Air is composed of much more than nitrogen, oxygen, and carbon dioxide. Even the relatively "clean" air of a normal (non-smoking) household or office environment contains a variety of microscopic particles, allergens and organic chemicals. Most of these compounds and materials are the result of normal human and animal activity, as well as plants, insects, cleaning products, and personal hygiene products.
Introducing dirt and certain soil- and plant-borne mold spores into the indoor environment normally occurs through open windows, doors, and from foot traffic. These particulates comprise most of what is found in normal indoor dust, both on surfaces (such as carpets) and in the air.
A normal indoor environment also includes trace quantities of volatile organic compounds (VOCs). These VOCs are the result of evaporation or off-gassing from carpeting, furniture and certain household or other chemical products. Most of these substances are harmless, but in a few cases, they represent potential hazards to a small number of susceptible individuals.
What causes indoor air quality problems?
It is helpful to distinguish normally occurring indoor substances from actual indoor "contaminants" or "pollutants." The latter have the potential to cause adverse health effects, both short-term (acute) and long-term (chronic). The Environmental Protection Agency (EPA) has published articles listing pollutants of concern. These pollutants can be classified into two types: 1) particulate and 2) gaseous.
1. Particulate Pollutants
These very small solid or liquid particles are light enough to float around in the air. They may include organic (i.e., carbon-containing) or inorganic compounds as well as dormant and/or living organisms. Of primary concern are non-visible particles that are small enough to penetrate deep into the lungs, where they can cause acute or chronic disease and health effects.
Larger particles —such as pollen, animal dander, or dust— are also a concern. Although they they do not tend to enter the lungs so deeply, they may aggravate asthma or cause an allergic reaction in sensitive individuals.
2. Gaseous Pollutants
These include combustion gases and organic chemicals that are not associated with particles. Hundreds of different gaseous chemical pollutants in indoor air come from combustion appliances, cigarette smoking, vehicle exhaust, building materials, furnishings, paints, adhesives, dyes, solvents, cleaners, deodorizers, personal hygiene products, pesticides and even the cooking of food or the metabolic processes of humans, animals or plants.
Health effects depend on the type and concentrations of gaseous pollutants, frequency and duration of exposure, and in the case of allergenic substances, individual sensitivity. Some of these chemicals are simply transient irritants, capable of causing short-lived reactions such as watering or burning of the eyes or nose, cough or other adverse reactions related to their unpleasant odor. For all but a few specific agents, the long-term health effects (at relatively low concentrations found in typical indoor environments) are unknown and/or not studied.
How can you remove pollutants?
Proper HEPA air filtration will help to reduce the exposure of occupants and workers to potentially dangerous particulates. Many HVAC systems do not adequately filter out harmful particulates, especially the smallest ones.
Portable air scrubbers with HEPA efficiency of 99.99% such as the Dri-Eaz HEPA 700 air scrubber or Mediclean AP 700 air purifier can help ensure that your indoor environment is healthy. The AP 700's UVC LED also attacks viruses and bacteria on the HEPA filter inlet, removing 99.98% of viruses on the HEPA filter.
Read "Why Indoor Air Quality Matters" for more information.
Learn more about indoor air quality at the EPA’s website, including a guide for school facility managers.
