There are three types of indoor air pollution:
- The pollution by chemical pollutants
- The pollution by biological contaminants
- The pollution by physical pollutants

Pollution by chemical pollutants

Many chemical pollutants accumulate indoors

Which are they? Here are a few of them:

• volatile organic compounds (VOC)
• semi-volatile organic compounds (sVOC)
• formaldehyde
• carbon monoxide (CO)
• particles
• Nitrogen oxides 
• asbestos
• radon
• aldehydes
• benzene
• tobacco smoke

What are the risks involved?

For chemical pollutants, we are exposed to two types of risks whose effects are specific to each type:

• Acute/short-term risks: short exposures to high concentrations of pollutants

Symptoms may include: irritation of the skin, of the mucous membranes or respiratory tract, nausea or headache, which could even lead to death in some cases due to poisoning by carbon monoxide (CO).

• Chronic/long-term risks: Long-term exposure to low but significant doses

Probable pathologies: respiratory, neurological or chronic cardiovascular as well as development of some cancers.

A few documented cases of these risks:

Exposures to substances present in indoor air are now associated with well-established effects on the health. This is true for the following substances:

• benzene and formaldehyde are classified as "Carcinogens" in humans by the International Agency for Research on Cancer (IARC) and the Scientific Committee of the European Chemicals Agency;
• asbestos, radon, benzene can cause the onset of some cancers;
• carbon monoxide (CO) emitted by faulty combustion appliances (cooking, heating, production of domestic hot water, etc.) is the cause of carbon monoxide poisoning. At very low doses, repeated regular exposure to CO can lead to lung or chronic heart diseases. Other pollutants (particles and nitrogen oxides) emitted by combustion appliances result in respiratory disorders (wheezing, decreased lung capacity, bronchial hypersensitivity, etc.) demonstrated by epidemiological studies that are specifically interested in the quality of indoor air;
• some chemical pollutants partly found in closed environments (such as some biocides, phthalates, etc.) become neurotoxic (attacking the nervous system) and/or toxic for reproduction (affecting the reproduction function).

Pollution from biological contaminants

Which are they?

• The moulds
• The legionella
• The animal allergens (from dust mites, cat, dog, etc.)

What are the risks involved?

The following biological contaminants may be the cause of allergic diseases:
• Moulds, dust mites, as well as the compounds released by them (mycotoxins, mite droppings, etc.);
• domestic allergens (from dust mites, cat, dog, etc.) in susceptible individuals.

A few documented cases of these risks:

- Epidemiological studies show an association between increased incidence of asthma or respiratory symptoms and the presence of mould (or excessive dampness) in indoor spaces. In Belgium, most Environmental Medicine related treatments in individuals, relate to moulds present in homes.

- The Sick Building Syndrome (or SBS) is defined as an excess of complaints and non-specific symptoms (headaches, concentration problems, fatigue, irritation of the skin or of the nose and eye mucous membranes, and of the upper respiratory tract) occurring among the occupants of non-industrial buildings. It has multifactorial origins involving environmental pollutions (presence of VOCs and bio-contaminants, noise, poor lighting, faulty ventilation, etc.) plus socio-professional and psychological factors, such as the working conditions and the organisation.

- In developing countries, the deterioration in the quality of indoor air, due to domestic combustion of coal and biomass fuels is a major public health problem. The World Health Organization (WHO) estimates 1.5 million deaths annually attributable to residential exposures to these fumes (acute infections of the lower respiratory tract, pulmonary diseases, lung cancer) (WHO, 2007).

Pollution by physical pollutants

Noise and electromagnetic waves can also have an effect on our health. For more information visit the pages dealing with these topics: Noise and electromagnetic waves.

6.2. Pathologies rencontrées au cours des audits Environnment-Santé_FR_ISP 

1. Dermatological
2. Digestive
3. Headaches
4. Widespread pain
5. Fatigue
6. Atypical discomfort
7. Tingling members
8. Mood disorders
9. Dizziness
10. Ophthalmic
11. VRI Asthma
12. VRI Respiratory problems
13. VRI Chronic infections
14. RSV Sneezing
15. RSV Chronic infections
16. RSV Cough