When contaminants are allowed to build and accumulate in a space, the negative effects can range from foul odors to physical symptoms such as damage to respiratory system, lung irritation, headaches, dizziness and nausea.
Indoor air contaminants can be categorized as being either particulate (solids) or molecular (gas).
- Particulates are induced into the respiratory system through breathing or though breaks in the skin
- Gaseous pollutants also enter the body through breathing however these pollutants are much more dangerous because they have the ability to penetrate beyond the lungs, into the bloodstream and around the entire body causing serious long term health concerns.
The source of indoor air contaminants can be internal or external and is caused by one or a combination of:
- chemical contaminants from outdoor air
- chemical contaminants from internal sources
- biological contaminants from living organisms
- or from poor ventilation
A list of commonly known contaminants is below as a reference:
- Chemical Odors
- Dust Mites
- Mold Spores
- Nitrogen Dioxide (NO2)
- Outdoor Air Pollution
- Pests, rats & cockroach droppings
- Second Hand Smoke
- Solvents, Paints, Adhesives
An allergen can be any substance that causes an allergic reaction in humans. Reactions vary from one person to the next. Allergens found in indoor air are primarily biological material such as pet dander, cockroach and other insect pest particles, pollen, bacteria, and mold spores. All of these materials are tiny particles, can become airborne, and thus, are easily inhaled.
Asbestos is a naturally-occurring mineral fiber commonly used in building construction materials for insulation and as a fire-retardant. If undamaged and unlikely to be disturbed, asbestos should be left alone. Disturbing asbestos materials through building renovations or asbestos removal can release asbestos fibers into the air, potentially leading to inhalation and accumulation within the lungs. Over time, a buildup of asbestos fibers embedded within the lung tissue may lead to serious lung diseases including asbestosis (irreversible lung scarring that can be fatal), lung cancer and mesothelioma, which is a cancer of the chest and abdominal linings.
Chemical odors are given off from a wide variety of materials: paints, solvents, pesticides, adhesives, particleboard, vinyl flooring and tiles, dry-cleaned clothes, toner from photocopiers, and cleaning agents used in your business and home. These odors can asthma attacks in people with sensitivity.
A wide range of hazardous chemicals (toxic, reactive, corrosive and explosive) can be found in science classrooms, labs, art classrooms and storage rooms, and can be used in building and grounds maintenance (e.g., cleaning and pest control). Chemicals that are outdated or unknown pose a particular danger in the event of a fire. Schools may inadvertently purchase chemicals in excessive amounts, store them incorrectly and dispose of them improperly. Exposure to these chemicals can occur during normal use and when they spill or leak.
Dust mites are tiny microscopic relatives of the spider and live on mattresses, bedding, upholstered furniture, carpets and curtains in your homes, offices and classrooms. These tiny creatures feed on the flakes of skin that people and pets shed daily and they thrive in warm and humid environments.
Formaldehyde is a chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes. This colorless, pungent-smelling gas can cause watery eyes, burning sensations in the eyes and throat, nausea, and difficulty in breathing in people exposed at elevated levels (above 0.1 parts per million). High concentrations may trigger attacks in people with asthma. There is also evidence that some people can develop a sensitivity to formaldehyde. It has also been shown to cause cancer in animals and may cause cancer in humans. Sources of formaldehyde include: pressed wood products (hardwood plywood wall paneling, particleboard, fiberboard); furniture made with these pressed wood products; combustion sources and environmental tobacco smoke; durable press drapes; and other textiles and glues.
Mercury is found in products such as fluorescent light bulbs, thermostats, thermometers, barometers, batteries and electrical switches and relays. Mercury can permanently damage the brain and kidneys, especially in developing fetuses. Exposure can occur through inhalation of vapors, skin contact (if mercury is accidentally spilled or leaked) or while using chemicals containing mercury. There are now non-mercury or low-mercury product substitutes. If a mercury spill or leak occurs, contact your local health department immediately. EPA encourages schools to prevent spills by removing all mercury compounds and mercury-containing equipment and by discontinuing their use.
Once formed, mold spores can proliferate quickly and efficiently throughout an indoor environment, especially a humid one. Molds and mildews release disease-causing airborne toxic mold spores.
Nitrogen Dioxide (NO2)
Is an odorless gas that can irritate your eyes, nose and throat and cause shortness of breath. NO2 can come from appliances inside your home that burn fuels such as gas, kerosene and wood. NO2 forms quickly from emissions from cars, trucks and buses, power plants and off-road equipment. Smoke from your stove or fireplace can trigger asthma.
Outdoor Air Pollution
Outdoor air pollution is caused by small particles and ground level ozone that comes from car exhaust, smoke, road dust and factory emissions. Outdoor air quality is also affected by pollen from plants, crops and weeds
Indoor Ozone is a colorless unstable toxic gas with a noticeable odor and when inhaled, it can damage the lungs and irritate the throat. Although ozone is found and is naturally produced in the atmosphere, it is also a main part of air pollution called smog. In the upper layer of the sky, ozone is helpful in protecting us from some of the effects of the sun. However, when it exists in the lower layer, close to the earth (outdoors and in our buildings and homes), it can be very harmful if we inhale it.
Pests, rats & cockroach droppings
The cockroach allergens stem from their shed outer coverings (cuticles), their saliva, and their eggs and feces. Once dried, these become airborne. Rat, cockroach and pest allergens can be found in house dust and bedding.
Radon is a colorless, odorless and tasteless radioactive gas that occurs naturally in almost all soil and rock. Radon can enter schools through cracks or other openings in their foundations. Radon is second only to smoking as the main cause of lung cancer in United States.
Second Hand Smoke
Second hand tobacco smoke can infiltrate indoor public areas via building entrances, exits, and ventilation systems, causing a serious degradation of indoor air quality. Tobacco smoke typically contains excessive amounts of carbon monoxide, arsenic, and other indoor air toxins that can cause or exacerbate respiratory illnesses.
Some biological contaminants trigger allergic reactions, including hypersensitivity pneumonitis, allergic rhinitis, and some types of asthma. Symptoms caused by biological pollutants include sneezing, watery eyes, coughing, shortness of breath, dizziness, lethargy, fever, and digestive problems. People who have noticed only mild allergic reactions, (or even no reactions at all), may suddenly find themselves very sensitive to particular allergens. Children, elderly people, and people with breathing problems, allergies, and lung diseases are particularly susceptible to disease-causing biological agents in the indoor air.
Central air conditioning systems and HVAC duct work can become breeding grounds for all of these allergen producing contaminants and can then distribute these contaminants through an home or office building.