What is PM2.5?
PM2.5 refers to fine inhalable particles with diameters 2.5 micrometers or smaller. To put that in perspective, a human hair is about 70 micrometers in diameter, making PM2.5 roughly 30 times smaller.
Why PM2.5 is Dangerous
Because of their tiny size, PM2.5 particles can:
- Bypass your nose and throat defenses
- Penetrate deep into your lungs
- Enter your bloodstream
- Reach vital organs including your heart and brain
Sources of PM2.5
PM2.5 comes from various sources including:
- Combustion: Vehicle exhaust, industrial emissions, power plants
- Wildfires: Major source of PM2.5 in western states
- Wood burning: Fireplaces and wood stoves
- Dust: Construction sites, unpaved roads
- Secondary formation: Chemical reactions in the atmosphere
Health Effects
Short-term exposure to PM2.5 can cause:
- Eye, nose, and throat irritation
- Coughing and difficulty breathing
- Asthma attacks
- Heart attacks in people with heart disease
Long-term exposure is linked to:
- Reduced lung function
- Chronic bronchitis
- Premature death in people with heart or lung disease
- Increased risk of lung cancer
Protection Strategies
- Monitor PM2.5 levels daily using the AQI
- Limit outdoor activities when levels are high
- Use N95 or KN95 masks during poor air quality days
- Run HEPA air purifiers indoors
- Keep windows closed during high pollution episodes