Main indoor air pollutants
Gases
Inorganic gases
Organic gases
Very volatile organic compounds
Very volatile organic compounds (VVOCs)
Volatile organic compounds
Volatile organic compounds (VOCs) are a large group of chemicals that easily become gases or vapors at room temperature. They are found in many common household products and building materials, and they can have a significant impact on indoor air quality (IAQ).
Semi-volatile organic compounds
Semi-volatile organic compounds (SVOCs)
Radon
Indoor air particles
Particulate matter (PM) is a mixture of solid particles and liquid droplets suspended in the air. These particles vary in size, composition, and origin, and their effects on human health depend on these characteristics.
PM is classified by its aerodynamic diameter, which is the size of a unit-density sphere with the same aerodynamic properties as the particle.
Coarse particles (PM10)
Coarse particles are inhalable particles, with diameters that are generally 10 micrometers and smaller.
Fine particles (PM2.5)
Fine particles are inhalable particles, with diameters that are generally 2.5 micrometers and smaller. Due to their small size, they can penetrate deep into the respiratory tract, reaching the lungs.
Ultrafine particles (PM0.1 )
Ultrafine particles (UFP) are a subset of particulate matter with a diameter of less than 0.1 micrometers. Due to their extremely small size, UFP can penetrate deep into the lungs and potentially enter the bloodstream, raising concerns about their health effects.
Biological agents
This category encompasses living organisms and their byproducts that can negatively affect indoor air quality.
Mold and Fungi
These microorganisms thrive in damp or humid indoor environments and can release mycotoxins, which can have carcinogenic, immunotoxic, cytotoxic, and mutagenic effects.◦
Bacteria
Similar to mold, bacteria can grow in damp conditions and cause health issues.◦
Viruses
These can be transmitted through the air, especially in poorly ventilated spaces.◦
Allergens
These substances can trigger the immune system, causing allergic reactions. Common indoor allergens include dust mites, pet dander, and pollen
Concentration limit values for main air pollutants
| Pollutant | Averaging period | Concentration limit value | Reference | ||
|---|---|---|---|---|---|
| Organic air pollutants | Benzene | - | no safe level | WHO 2010 | |
| Naphthalene | annual | 10 | μg/m3 | WHO 2010 | |
| Polycyclic aromatic hydrocarbons | no safe level | WHO 2010 | |||
| Tetrachloroethylene | annual | 250 | μg/m3 | WHO 2010 | |
| Trichloroethylene | WHO 2010 | ||||
| Formaldehyde | 30-minute | 100 | μg/m3 | WHO 2010 | |
| Particulate matter | PM2.5 | 24-hour
annual |
15
5 |
μg/m3 | WHO 2021 |
| PM10 | 24-hour
annual |
45
15 |
μg/m3 | WHO 2021 | |
| O3 | 8-hour
peak season |
100
60 |
μg/m3 | WHO 2021 | |
| SO2 | 10-minute
24-hour |
500
40 |
μg/m3 | WHO 2021 | |
| Inorganic gaseous pollutants | NO2 | 1-hour
24-hour annual |
200
25 10 |
μg/m3 | WHO 2021 |
| CO | 15-minute
1-hour 8-hour 24-hour |
100
35 10 4 |
mg/m3 | WHO 2021 | |
| Radon | |||||