Air Quality Inside Buildings
Air pollution, both indoor and outdoor, is a significant cause of health
problems worldwide. Home environments contain airborne allergens, infections,
irritants and toxins that can reduce the quality of life and cause disease.
Indoor work and living environments concentrate air contaminants and create
Every year, approximately 1,000 new chemicals are developed and added to the
70,000 chemicals, 9 million mixtures, formulations and blends of chemicals
already in commercial use. Some of these chemicals are purchased for home use,
others pollute work environments. Workers contaminated with industrial and
agricultural chemicals bring some home on the clothing and skin. Few of these
chemicals have been adequately assessed for their potential toxicity, either
individually or in combination with other chemicals.
Indoor air is often more polluted than outdoor air. A decrease in
indoor air quality is the result of reduced ventilation and efficient
construction practices, sealing homes and office buildings from the outdoor
environment. Reduced ventilation contributes to the "Sick Building Syndrome"
(SBS) with symptoms such as headache, fatigue, malaise, mental confusion, eye
and throat irritation, coughing and wheezing.
Air inside buildings contains local aerosols that are more concentrated than
outdoor air. The term "dust" refers to the larger particles in the aerosol that
settle on walls and furniture. A smoker in the living room of a house produces a
toxic aerosol that permeates the rest of the house. Smoke particles settle on
walls and every object in a room so that a smoker leaves a trail of
contamination that non-smokers smell as soon as they enter the room.
Indoor air contains a living aerosol of microorganisms that infect or trigger
allergic reactions. Spores of bacteria and fungi are microscopic and may persist
for months or years.
The abundance of microorganisms, even in a very clean house, surprises most
people who have tests done to assess air quality. Insects and their excretions
and body parts form part of the aerosol. Allergy to dust mites is often
recognized. Other mites are common and are usually not recognized.
See Airborne Fungal Diseases
Chemicals Found in Indoor Air
Many hazardous chemicals are used at home. Studies have shown that cancer
risks from airborne chemicals can be higher for home environments than for
hazardous waste disposal sites. The concentration of chemicals is determined by
the airflow (or lack of it), heating appliances, the use of cleaners, paints,
adhesives, types of furnishings and the smoking habits of the inhabitants.
- 1,1,1-Trichloroethane Benezene
- Formaldehyde Alipthatic Hydrocarbons
- Chlordane Chloroform
- Styrene Trichloroethylene
- Toluene Xylene
- Dichloromethane Tetrachloroethylene
- Alcohols N-Hexanol
- Ethyl Acetate Acetone
- Radon 4-Phenylcyclohexene
- Carbon Monoxide Carbon Dioxide
- Polycyclic Aromatic Hydrocarbons
There are 80 or more main chemical components found in cigarette smoke and a
wide variety of toxins created from the degradation and out-gassing of synthetic
and treated materials and plastics. Indoor air is often a greater source of
exposure to hazardous chemicals than is outdoor exposure according to a
acareful study by the US Federal Environmental Protection Agency (EPA) The EPA looked for 20
chemicals in a variety of locations and found 11 chemicals at all locations -
1,1,1-trichloroethane, p-xylene, ethylbenzene, tetrachloroethylene, o-xylene,
p-dichlorobenzene, chloroform, trichloroethylene, and carbon tetrachloride.
In New Jersey, nighttime readings of domestic indoor air exceeded outdoor air
concentrations in 28 out of 30 cases. In North Carolina and North Dakota the
indoor air pollution was even stronger (because in NC and ND the outdoor air is
cleaner): in 17 out of 18 cases, inside air exceeded the levels found in outdoor
air, usually by a factor of 5 to 10. The chemicals on peoples' breath were
closely correlated with their activities of the previous 12 hours. Averages for
personal air exceeded outdoor averages for every chemical in every season,
usually by a factor of 2 to 5. This means that, in a typical day at work and at
home, people breathed in 2 to 5 times more hazardous chemical than they would
have if they had sat in their back yards for 24 hours. This was true even if the
people lived within a mile of a source of industrial air pollution.