Cycling Air Quality Guide

Cycling-Specific AQI Thresholds

Exertion Level Considerations

Easy Pace / Recovery Rides (Zone 1-2)

• Safe up to AQI 100 for most cyclists
• AQI 101-150: Reduce duration by 30%, stay in zone 1
• AQI 151+: Move to indoor trainer
• Breathing rate: 2-3x resting

Tempo Rides (Zone 3)

• Safe up to AQI 75
• AQI 76-100: Reduce power output by 10-15%
• AQI 101+: Cancel outdoor ride
• Breathing rate: 4-5x resting

Threshold / Sweet Spot (Zone 4)

• Only recommended below AQI 70
• AQI 70-100: Switch to easier ride
• AQI 100+: Indoor trainer only
• Breathing rate: 6-7x resting

High-Intensity Intervals (Zone 5+)

• Requires AQI below 60 for safety
• Maximum breathing rate: 8-10x resting
• AQI 60+: Postpone or do indoor

Long Endurance Rides (3+ hours)

• Safe up to AQI 90 for trained cyclists
• AQI 91-120: Reduce duration and intensity
• AQI 120+: Cancel or significantly shorten ride

Cycling-Specific Air Quality Factors

Road Cycling Considerations

• Traffic Exposure: Cyclists on roads breathe concentrated exhaust fumes
• Speed Effect: Higher speeds increase air intake volume
• Route Matters: Busy roads can have 2-3x higher pollution than bike paths
• Urban Canyons: Tall buildings trap pollution at street level

Mountain Biking Advantages

• Forest trails typically have 30-50% better air quality than roads
• Higher elevation means cleaner air
• Distance from traffic reduces pollutant exposure
• Tree canopy provides natural air filtration

Mask Recommendations for Cyclists

When Masks Make Sense

• Commuters in AQI 101-150: Sport N95 or Cambridge Mask recommended
• Necessary errands in AQI 151-200: Mask required, reduce speed significantly
• AQI 201+: No outdoor cycling regardless of mask

Cycling Masks Best Practices

• Use sport-specific masks with breathing valves (Respro, Vogmask, Cambridge Mask)
• Expect 20-30% reduction in power output when masked
• Avoid N95 masks without valves for cycling - too restrictive
• Clean reusable masks after every ride
• Replace filters every 50-100 miles or monthly
• Practice breathing with mask on easy rides first

Masks Not Recommended For:

• High-intensity intervals - breathing restriction too severe
• Races or group rides - performance penalty too high
• Mountain biking descents - reduced oxygen during technical sections

Alternative Indoor Options

Smart Trainer Options

• Zwift / RGT: Virtual riding with group workouts
• TrainerRoad: Structured training plans
• Rouvy: Augmented reality routes
• Sufferfest: High-intensity training videos

Indoor Cycling Alternatives

• Spin classes at gyms with good air filtration
• Rollers for skill work (lower intensity)
• Mountain bike skills park if indoors available
• Stationary bike at gym

Best Times of Day for Cycling

Early Morning (5 AM - 8 AM)

Optimal choice: Lowest AQI and minimal traffic. Ozone levels low. Road cycling safest before commuter traffic begins. Aim for before 7 AM in cities.

Late Morning (9 AM - 11 AM)

Acceptable: AQI starts rising. Traffic decreasing. Good compromise if early morning isn't possible.

Midday (11 AM - 3 PM)

Avoid when possible: Peak ozone formation especially in summer. AQI can be 30-50 points higher. Only ride if morning AQI was below 40.

Late Afternoon (3 PM - 6 PM)

Not ideal: Rush hour traffic pollution. Still elevated ozone. Wait until after 6:30 PM if possible.

Evening (6:30 PM - Dark)

Second best option: Ozone dissipates after sunset. Traffic pollution decreasing. Good alternative to morning rides.

Best Cities for Cycling Based on Air Quality

Premier Cycling Cities (Average AQI Below 35)

• Portland, OR: Extensive bike infrastructure, clean Pacific air
• Boulder, CO: Mountain air, bike-friendly culture
• Burlington, VT: Clean New England air, great bike paths
• Santa Barbara, CA: Coastal air quality, year-round riding
• Bellingham, WA: Clean Pacific Northwest air

Excellent Cycling Cities (Average AQI 35-50)

• Seattle, WA: Bike lanes, generally good air
• Minneapolis, MN: Extensive trails, clean air most of year
• San Francisco, CA: Ocean breezes, challenging climbs
• Fort Collins, CO: Bike culture, mountain air
• Madison, WI: Bike-friendly, good air quality

Good with Seasonal Challenges (Average AQI 50-70)

• Los Angeles, CA: Great winter, summer ozone issues
• Phoenix, AZ: Excellent winter, avoid summer
• Austin, TX: Good spring/fall, challenging summer
• Denver, CO: Great summer, winter inversions

Route Planning for Air Quality

Choose Clean Air Routes

• Waterfront paths: Ocean/lake breezes disperse pollution
• Dedicated bike trails: Away from traffic = better air
• Residential streets: 40-60% less pollution than arterials
• Parks and greenways: Trees filter air naturally
• Higher elevation: Above inversion layers in valleys

Avoid High-Pollution Routes

• Highways and freeways: 3-5x higher pollution
• Industrial areas: Multiple pollution sources
• Truck routes: Diesel exhaust especially harmful
• Tunnels: Trapped concentrated exhaust
• Bus corridors: Repeated exposure to diesel

Safety Checklist for Cyclists

Special Considerations

Bike Commuting in Poor Air Quality

• AQI 101-150: Consider sport mask, reduce pace, add 25% time
• AQI 151+: Use public transit, carpool, or work from home if possible
• Choose longer route with less traffic over shorter busy route
• Shower and change immediately upon arrival

Group Rides and Cycling Clubs

• Ride leaders should check AQI before announcing ride
• Consider canceling if AQI forecast exceeds 100
• Announce AQI at start and let riders opt out
• Plan alternative indoor group Zwift ride

Cyclists with Asthma

• Carry rescue inhaler in easily accessible jersey pocket
• Use preventive inhaler 15 minutes before ride when AQI is 51-100
• Avoid outdoor cycling above AQI 100
• Extend warm-up to 15-20 minutes
• Have emergency contact information on bike ID

Racing and Events

Race organizers should monitor AQI and have contingency plans. Participants should know their limits. If AQI exceeds 100 on race day, consider withdrawing - your health is more important than one race result.