The Air Infiltration and Ventilation Centre (AIVC) in Europe recently evaluated existing guidelines, hazard assessments, cumulative risk, and health impact for indoor air contaminants. AIVC then proposed a hierarchy of high-priority indoor air pollutants for residential ventilation standards. Experts call these high-priority contaminants: contaminants of concern (COCs). COCs are sometimes called pollutants of concern (POCs)
Identifying Contaminants of Concern
For chronic exposure, AIVC identified the following high-priority contaminants, ranked by population impact.
- particles,
- mold and moisture,
- formaldehyde,
- acrolein.
For acute exposure, experts propose the following contaminants without ranking them because of the lack of information in the literature: acrolein, chloroform, carbon monoxide, formaldehyde, NO2, PM2.5. Also, even if humidity itself isn’t a contaminant, experts considers humidity as a health concern because of the risk of mold and dust mites.
High-priority pollutants: chronic exposure, ranked by health impact | High-priority pollutants for acute exposure |
1. Particulate matter
2. Mold and moisture 3. Formaldehyde 4. Acrolein |
Acrolein
Chloroform Carbon monoxide Formaldehyde NO2 PM2.5 |
Quantifying the Harm Caused by Contaminants
IAQ experts use two common methods for quantifying the effects of COCs.
- Animal experiments that provide the following values.
- Exposure limit values (ELVs)
- Toxicity reference values (TRVs)
- Indoor air guideline values (IAGVs)
- These three values can’t effectively combine into an integrated health assessment
- Disability-adjusted life years (DALYs) that provide a versatile assessment of contaminant effect on humans. IAQ experts can add DALYs for individual contaminants to characterize the health effects of a particular air mass, depending on the concentration of various contaminants it contains.

Further Reading
Burden of disease from Household Air Pollution for 2012. World Health Organization.WHO, 2014.
What’s in the Air We Breathe.” ASHRAE Journal (2010): 72-77. “