Detailed Methodology for Studying Indoor Air Pollution

Indoor air pollution is caused by high levels of contaminants that become trapped indoors because of poor ventilation. Some sources of contamination include asbestos from building materials, lead from lead-based paint and mold from water damage. Generally, the first sign of indoor air pollution is that inhabitants become ill. There is a specific methodology to follow when studying indoor air pollution, but some sources of contamination, for example radon, are odorless and require testing before habitation occurs.

Indoor Air Pollution

• Indoor air pollution can be caused by various contaminants: carbon monoxide, nitrogen dioxide, sulfur dioxide, biologicals (like animal dander, mold, dust mites), fungi, volatile organic compounds (like formaldehyde, pesticides), airborne lead and mercury vapors, asbestos and radon. Sources of these indoor contaminants are paint, carpeting, furniture, building materials, pest fumigation, or outside sources that become trapped indoors because of poor ventilation.

Indoor Air Pollution Diagnostic

• Generally, the first sign of indoor air problems is when someone becomes sick. Health care providers are guided to perform a diagnostic questionnaire to identify potential indoor air problems for unexplained asthma, other respiratory ailments and rashes. The diagnostic eliminates sources of contaminants by asking questions like:

  When did you first become sick?

  Are you sick all the time, or does it come and go with the times of the day, week or seasons?

  Do you feel better when you go outside? Do you feel sick when you return inside?

  Has the indoor space been redecorated or refurnished?

  Have you started using pesticides or different cleaning products, or even craft supplies?

  Does smoking occur inside?

  Have you recently renovated?

  Are new hobbies being practiced indoors? Do you have a new pet?

  How many people in your home have the same symptoms? (If more than one, it indicates a common source or is communicable)

  The answers to these questions determine whether indoor air sampling is necessary.

Indoor Air Sampling

• The purpose of indoor air sampling is to identify potential sources of contamination and/or problems with ventilation. Indoor air sampling is very expensive. It requires the correct selection of measurement devices and detailed information on the building type, the number of occupants, the identification of potential contamination sources and consideration of the temporal and spatial variation of contaminant emissions.

Measurement Devices

• There are a variety of indoor air sampling devices. Diffusion-controlled passive monitors measure gaseous pollutants within a room. Solid sorbent diffusive samplers measure exposure to contaminants and are worn on inhabitants. Small-scale environmental chambers are used to test emissions from products like carpets but only sample small sections of larger materials. Large-scale environmental chambers test emissions from assemblages of products, like furniture, or can test emissions from application processes, like paint, but materials must be transported off-site.

Risk Assessment

• After data is collected, a risk assessment is conducted to identify the chance of cumulative harmful effects to humans as a result of exposure to a contaminant based on the collected sample data. The risk depends on how much of the contaminant is present, how much contact occurs with the contaminant (exposure) and the inherent toxicity of the contaminant. For indoor air pollution, exposure is dependent upon exposure.

  If there is a true indoor air pollution problem, the completed risk assessment will guide source removal and/or increased ventilation options. An air purifier will not treat indoor air pollution, and there are significant human health risks associated with ozone air cleaners.