Running-Specific AQI Thresholds
AQI 0-50: Excellent Running Conditions
Perfect for all running intensities, intervals, and long runs. No restrictions.
AQI 51-100: Good for Most Runners
Safe for normal training. Sensitive individuals may notice slight discomfort during intense efforts.
AQI 101-150: Modify Your Run
Reduce intensity by 20-30%. Limit interval workouts. Sensitive groups should reduce duration.
AQI 151-200: Indoor Running Recommended
Move to treadmill if possible. If running outside, keep easy pace and limit to 20-30 minutes.
AQI 201+: Avoid Outdoor Running
Do not run outdoors. Health risks outweigh training benefits.
Exertion Level Considerations
Easy Runs (Conversational Pace)
- Safe up to AQI 100 for most people
- AQI 101-150: Reduce duration by 25%, monitor breathing
- AQI 151+: Move indoors
Tempo Runs (Comfortably Hard)
- Safe up to AQI 75 without modification
- AQI 76-100: Reduce intensity slightly
- AQI 101+: Skip or move to treadmill
Interval Training (High Intensity)
- Only recommended below AQI 75
- AQI 76-100: Consider postponing or doing easy run instead
- AQI 101+: Do not attempt outdoors
Long Runs (60+ minutes)
- Safe up to AQI 100
- AQI 101-150: Reduce pace significantly, take walk breaks
- AQI 151+: Split into shorter sessions indoors
Mask Recommendations for Runners
When to Consider a Running Mask
- AQI 101-150: N95 or KN95 mask recommended for sensitive individuals
- AQI 151-200: Sport-specific N95 mask essential if running outdoors
- AQI 201+: No mask is adequate protection for running
Running Mask Best Practices
- Use masks designed for athletic activity with breathing valves
- Expect 15-25% reduction in performance when masked
- Take breaks more frequently to manage breathing
- Stay well hydrated as masks increase perceived effort
- Replace masks every 3-5 runs or when breathing becomes difficult
Alternative Indoor Options
When Air Quality Is Poor
- Treadmill Running: Best option to maintain training consistency
- Indoor Track: Available at many gyms and recreation centers
- Cross-Training: Stationary bike, rowing machine, elliptical
- Strength Training: Use poor air quality days for gym work
- Swimming: Excellent alternative that maintains cardiovascular fitness
Best Times of Day for Running
Morning Runs (5 AM - 9 AM)
Best choice: Typically lowest AQI levels. Ozone has not yet formed, and traffic pollution is minimal. Aim for before 7 AM in urban areas.
Midday Runs (11 AM - 3 PM)
Avoid if possible: Peak ozone formation. AQI typically 20-40 points higher than morning. Only run during midday if morning AQI was below 50.
Evening Runs (6 PM - 9 PM)
Second best: Ozone decreases after sunset, but traffic pollution may be elevated during rush hour. After 7 PM is usually better than 6 PM.
Night Runs (After 9 PM)
Good for air quality: Low pollution levels, but consider safety and impact on sleep schedule.
Best Cities for Running Based on Air Quality
Excellent Year-Round Running Cities (Average AQI Below 30)
- Honolulu, HI - Consistent ocean breezes
- Anchorage, AK - Clean arctic air
- Burlington, VT - Mountain air quality
- Portland, ME - Coastal ventilation
- Bellingham, WA - Pacific Northwest air
Good Running Cities (Average AQI 30-50)
- Seattle, WA - Rarely exceeds moderate
- San Diego, CA - Coastal air circulation
- Colorado Springs, CO - Mountain elevation
- Raleigh, NC - Good air flow patterns
- Minneapolis, MN - Generally clean air
Cities Requiring AQI Monitoring (Average AQI 50-75)
- Los Angeles, CA - Summer ozone issues
- Phoenix, AZ - Dust and summer heat
- Atlanta, GA - Humid summer conditions
- Denver, CO - Winter inversions
- Salt Lake City, UT - Winter air quality challenges
Health Risks by Running Intensity
Light Running (Below 60% Max HR)
- Minimal risk up to AQI 100
- Breathing rate 2-3x normal
- Safe for most people with precautions up to AQI 150
Moderate Running (60-75% Max HR)
- Breathing rate 4-5x normal
- Significantly increased pollutant exposure
- Risk becomes concerning above AQI 100
- Not recommended above AQI 150
Hard Running (75-90% Max HR)
- Breathing rate 6-8x normal
- Maximum pollutant intake
- Only safe below AQI 75
- Avoid entirely above AQI 100
Safety Checklist for Runners
Before Every Run
- ✓Check current AQI and forecast for your run duration
- ✓Review wind direction (avoid running downwind of pollution sources)
- ✓Plan route away from major roads and industrial areas
- ✓Have indoor backup plan ready
- ✓Carry phone to check AQI if conditions change
During Your Run
- ✓Monitor breathing - difficulty breathing is a sign to stop
- ✓Watch for eye irritation, coughing, or chest tightness
- ✓Reduce pace immediately if symptoms develop
- ✓Head home early if air quality seems worse than forecast
After Your Run
- ✓Shower promptly to remove pollutants from skin and hair
- ✓Note any symptoms in training log
- ✓Wash running clothes separately from indoor clothes
- ✓Rest longer if you experienced any breathing difficulty
Special Considerations
Training for Races
If you have an important race coming up, never compromise your health for a workout. Missing one training run is better than developing respiratory issues that could sideline you for weeks.
Running Clubs and Group Runs
Group run organizers should check AQI and communicate plans. Consider canceling or moving indoors if AQI exceeds 100. Remember that participants have varying sensitivity levels.
Runners with Asthma
- Keep rescue inhaler accessible on all runs
- Use preventive inhaler before running when AQI is 51-100
- Avoid outdoor running above AQI 100
- Extend warm-up period to allow airways to adjust