Indoor Air Pollutants
Learning Objectives
Students will be able to:
- Identify the major categories of indoor air pollutants
- Describe common sources of each pollutant type
- Explain health effects associated with indoor pollutants
- Apply knowledge to identify pollutant sources in their own environments
Categories of Indoor Air Pollutants
Gases
- CO2 (carbon dioxide)
- CO (carbon monoxide)
- NO2 (nitrogen dioxide)
- Radon
Particles
- PM2.5 (fine particles)
- PM10 (coarse particles)
- Dust and allergens
- Smoke particles
VOCs
- Formaldehyde
- Benzene
- Cleaning product fumes
- Paint and adhesive vapors
Biological
- Mold spores
- Bacteria
- Viruses (aerosols)
- Pet dander
What Are VOCs?
Volatile Organic Compounds (VOCs) are chemicals that evaporate easily at room temperature. "Volatile" means they turn from liquid to gas quickly. Many household products release VOCs into the air.
Common Indoor Pollutant Sources
| Pollutant | Common Sources | Health Effects |
|---|---|---|
| CO2 | Human breathing, combustion | Drowsiness, poor concentration at high levels |
| CO | Gas stoves, heaters, car exhaust, fireplaces | Headaches, dizziness, potentially fatal |
| PM2.5 | Cooking, candles, smoking, wildfires | Respiratory irritation, cardiovascular effects |
| Formaldehyde | New furniture, flooring, pressed wood | Eye/nose irritation, respiratory issues |
| VOCs (general) | Paints, cleaners, air fresheners, markers | Headaches, nausea, irritation |
| Radon | Ground seepage (natural radioactive gas) | Lung cancer (long-term exposure) |
| NO2 | Gas stoves, space heaters | Respiratory irritation, asthma triggers |
Carbon Monoxide: The Silent Killer
Why is CO dangerous?
- Colorless and odorless - you can't see or smell it
- Binds to hemoglobin - blocks oxygen transport in blood
- Produced by incomplete combustion - gas appliances, cars, generators
- Can be fatal - causes ~400 deaths/year in the US
Protection: CO detectors on every floor, proper appliance ventilation, never run cars/generators indoors
Particulate Matter Sizes
Particle size determines how deep into your lungs particles can travel:
PM10
Dust, pollen
<10 micrometers
Stopped in nose/throat
PM2.5
Smoke, combustion
<2.5 micrometers
Reaches deep lungs
Ultrafine
Combustion byproducts
<0.1 micrometers
Enters bloodstream
For comparison: a human hair is about 70 micrometers wide. PM2.5 particles are about 30 times smaller!
Activity: Pollutant Source Hunt
Walk through your school or home and identify potential pollutant sources:
| Location | Potential Sources Found | Pollutant Type |
|---|---|---|
| Kitchen | Example: Gas stove, toaster | CO, NO2, PM2.5 |
| Bathroom | ||
| Classroom | ||
| Art Room | ||
| Gym/Cafeteria |
Reducing Indoor Pollutants
Source Control
- Use low-VOC products
- Avoid burning candles/incense
- Maintain gas appliances
- Remove shoes at door
Ventilation
- Open windows when possible
- Use exhaust fans (kitchen, bath)
- Run HVAC fan
- Check that vents aren't blocked
Filtration
- Use HEPA filters
- Change HVAC filters regularly
- Run air purifiers (or CR boxes!)
- Vacuum with HEPA filter
Monitoring
- Install CO detectors
- Test for radon
- Use CO2 monitors
- Watch for mold/moisture
Key Takeaway
Indoor air often contains more pollutants than outdoor air because pollutants get trapped inside. We spend about 90% of our time indoors, so understanding and controlling these pollutants is critical for our health. The three strategies are: control sources, improve ventilation, and filter the air.