Indoor Air Quality Parameters to Know for Environmental and Occupational Health

Indoor air quality is crucial for health and well-being, impacting comfort, productivity, and safety. Key parameters like temperature, humidity, and pollutants can significantly affect respiratory health and overall quality of life in both residential and occupational settings.

1. Temperature

   • Affects occupant comfort and productivity; optimal range is typically between 68°F and 72°F (20°C to 22°C).
   • High temperatures can lead to heat stress and exacerbate respiratory issues.
   • Temperature fluctuations can influence the growth of biological contaminants.

2. Relative Humidity

   • Ideal indoor relative humidity levels are between 30% and 50% to prevent mold growth and dust mite proliferation.
   • High humidity can lead to condensation, promoting mold and mildew.
   • Low humidity can cause respiratory irritation and dry skin.

3. Carbon Dioxide (CO2)

   • Elevated CO2 levels (above 1000 ppm) can indicate poor ventilation and lead to drowsiness and decreased cognitive function.
   • Normal indoor levels typically range from 400 to 1000 ppm.
   • Monitoring CO2 can help assess overall indoor air quality and ventilation effectiveness.

4. Carbon Monoxide (CO)

   • A colorless, odorless gas that can be lethal at high concentrations; safe levels are below 9 ppm.
   • Common sources include gas appliances, vehicles, and tobacco smoke.
   • Chronic exposure can lead to headaches, dizziness, and impaired cognitive function.

5. Particulate Matter (PM2.5 and PM10)

   • PM2.5 (particles ≤2.5 micrometers) can penetrate deep into the lungs and enter the bloodstream, causing serious health issues.
   • PM10 (particles ≤10 micrometers) can cause respiratory problems and aggravate existing conditions.
   • Sources include combustion processes, dust, and biological materials.

6. Volatile Organic Compounds (VOCs)

   • Emitted from various sources, including paints, cleaning products, and building materials; can cause short- and long-term health effects.
   • Common VOCs include benzene, formaldehyde, and toluene.
   • High levels can lead to headaches, dizziness, and respiratory irritation.

7. Formaldehyde

   • A common VOC found in building materials, furniture, and household products; can cause irritation of the eyes, nose, and throat.
   • Long-term exposure is linked to respiratory issues and certain cancers.
   • Recommended indoor levels are below 0.1 ppm.

8. Radon

   • A naturally occurring radioactive gas that can accumulate indoors, especially in basements and lower levels.
   • Long-term exposure is the second leading cause of lung cancer after smoking.
   • Recommended action level is 4 pCi/L; testing is essential for homes and buildings.

9. Biological Contaminants (mold, bacteria, dust mites)

   • Mold can trigger allergies, asthma, and other respiratory issues; thrives in damp environments.
   • Dust mites are a common allergen found in bedding and upholstery; they thrive in humid conditions.
   • Bacteria can cause infections and exacerbate respiratory conditions; proper cleaning and humidity control are essential.

10. Ventilation Rate (air exchange rate)

    • Refers to the amount of outdoor air introduced into a space; essential for diluting indoor pollutants.
    • Recommended ventilation rates vary by building type and occupancy; ASHRAE guidelines provide standards.
    • Poor ventilation can lead to increased levels of CO2, VOCs, and other pollutants, impacting health and comfort.