How to Check Air Quality Before Your Event
Start with the official numbers. Pull the AQI and the hourly forecast for your venue's ZIP code from AirNow.gov (the EPA's public air quality service) or from our current AQI alerts, and estimate how safe your event window is with the safe outdoor time calculator. Because ozone climbs through hot afternoons and wildfire smoke can shift within hours, check again the morning of and roughly three hours before doors open — the forecast matters more than a single spot reading.
It helps to know what the numbers mean. AirNow reports AQI in six official categories: Good (0–50), Moderate (51–100), Unhealthy for Sensitive Groups (101–150), Unhealthy (151–200), Very Unhealthy (201–300), and Hazardous (301+). Our guide to understanding AQI breaks down each level. The event-specific limits below are practical planning guidelines built on top of those categories — they are not medical advice, and you should defer to AirNow, local health authorities, and venue policies when they set stricter rules.
Event Planning AQI Thresholds
AQI 0-50: Perfect Event Conditions
All outdoor events safe. No modifications needed.
AQI 51-100: Safe with Awareness
Events proceed normally. Announce AQI to attendees. Provide shaded rest areas.
AQI 101-150: Modify Event
Shorten duration. Reduce physical activities. Provide rest areas. Consider postponing.
AQI 151-200: Move Indoors or Cancel
Outdoor events not recommended. Move to indoor venue if possible.
AQI 201+: Cancel Outdoor Events
Do not hold outdoor gatherings. Serious health risk.
Event Type Guidelines
Active Events (Races, Sports Events, Field Days)
- Safe up to: AQI 75
- AQI 76-100: Reduce intensity, longer breaks
- AQI 101+: Cancel or significantly modify
- Participants breathe heavily, maximum pollutant exposure
Moderate Activity (Festivals, Fairs, Outdoor Markets)
- Safe up to: AQI 100
- AQI 101-150: Shorten hours, provide air-conditioned rest areas
- AQI 151+: Cancel or move indoors
Seated Events (Concerts, Movies, Ceremonies)
- Safe up to: AQI 125
- AQI 126-150: Consider postponing
- AQI 151+: Move indoors
- Minimal exertion but extended exposure
Children's Events (Birthday Parties, School Events)
- Safe up to: AQI 75
- AQI 76-100: Reduce active games
- AQI 101+: Move indoors
- Children more vulnerable than adults
Event Modifications by AQI Level
AQI 51-100: Enhanced Monitoring
- Post AQI level at event entrance
- Provide water stations
- Ensure shaded areas available
- Make announcements about sensitive groups
- Have first aid staff aware of air quality symptoms
AQI 101-150: Significant Modifications
- Reduce event duration by 30-50%
- Eliminate or reduce physical activities
- Provide air-conditioned rest areas
- Offer N95 masks to attendees
- Allow attendees to leave without penalty
- Consider canceling and rescheduling
Pre-Event Planning
Booking and Scheduling
- Check historical AQI data for date/location
- Avoid peak ozone months for outdoor events
- Schedule for morning or evening when possible
- Have indoor backup venue contracted
- Include weather/air quality cancellation clause
Communication Plan
- Establish AQI threshold for cancellation
- Create notification system for attendees
- Designate person to monitor AQI day-of
- Prepare messaging for postponement
Wildfire Smoke Contingency Plan
Wildfire smoke is the hardest scenario to plan for because it can push AQI from Good to Unhealthy in a matter of hours and lingers unpredictably. If your event falls in or near wildfire season, build a smoke plan on top of your normal air-quality checks — see our wildfire smoke guide for how smoke behaves and what it does to AQI.
- Track active fires and smoke forecasts in the days before the event, not just the day-of AQI.
- Have a clear, pre-agreed AQI number that triggers moving indoors or postponing, and communicate it to attendees in advance.
- Secure an indoor backup venue with real filtration — a well-sealed building with HVAC or portable air cleaners, not an open-sided tent, which does little against fine smoke particles (PM2.5).
- Stock N95 or KN95 respirators for staff and vulnerable attendees; cloth and surgical masks do little against smoke particles.
- Keep refund, reschedule, and notification messaging drafted ahead of time so a fast-moving smoke event doesn't catch you flat-footed.
- When smoke is heavy, err toward canceling outdoor exertion — smoke exposure is a health risk, especially for children, older adults, and anyone with heart or lung conditions.
Planning an indoor backup venue? Make sure its air is clean too:
Protect Your Indoor Air
With an AQI of 101 driven by fine particulate matter (PM2.5), outdoor pollution is seeping indoors. A True-HEPA purifier captures up to 99.97% of the PM2.5, wildfire smoke and fine particles behind this reading. On unhealthy days like today, size up to a higher-CADR unit so it can clear the whole living area quickly.
Compare top-rated True-HEPA purifiers:
Prices are approximate and subject to change. As an Amazon Associate, we earn from qualifying purchases at no extra cost to you.
Day-of-Event Protocols
Event Staff Checklist
- ✓Check AQI 3 hours before event start
- ✓Review hourly forecast for event duration
- ✓Set up air quality information signs
- ✓Ensure first aid staff briefed on air quality symptoms
- ✓Designate person to monitor AQI during event
- ✓Have plan to evacuate to indoor space if needed
Venue Selection
Better Air Quality Venues
- Parks away from roads: Trees filter air
- Waterfront locations: Better air circulation
- Higher elevation: Above street-level pollution
- Suburban/rural venues: Less traffic pollution
Venues to Avoid
- Adjacent to highways: High traffic pollution
- Industrial areas: Multiple pollution sources
- Urban centers: Concentrated pollution
- Valleys: Pollution can be trapped
Special Event Types
Outdoor Weddings
- Check AQI forecast week before
- Have indoor backup plan (tent with AC or indoor venue)
- Consider evening ceremony for better air quality
- Communicate AQI concerns to elderly guests
- Spring and fall typically better than summer
Music Festivals and Concerts
- Multi-day events need contingency plans
- Provide covered rest areas with fans/AC
- Reduce set times if AQI elevated
- Medical staff should monitor for pollution symptoms
- Consider partial refunds if AQI causes cancellation
Sports Events and Tournaments
- Have clear AQI cancellation policy
- Schedule games for morning when possible
- Modify rules (shorter games, more subs) when AQI elevated
- Youth events more restrictive than adult
Graduation Ceremonies
- Traditionally held in early summer (high ozone season)
- Evening ceremonies better than afternoon
- Have indoor auditorium backup
- Consider shortened ceremony if AQI elevated
- Provide shade structures
Attendee Safety
Information to Provide
- Current AQI level posted at entrance
- Signs explaining AQI categories
- Guidance for sensitive groups
- Location of rest areas
- Water station locations
Sensitive Groups
- Children
- Elderly attendees
- People with respiratory conditions
- Pregnant women
- People with heart disease
Best Seasons for Outdoor Events
Best Air Quality
- Fall: Generally cleanest air, comfortable temperatures
- Spring: Good air quality, watch for pollen
- Winter: Low ozone but watch for inversions
Challenging Seasons
- Summer: Peak ozone season, highest AQI days
- Wildfire season: West Coast summer/fall variability
Best Cities for Outdoor Events
Reliable Clean Air
- Seattle, WA - Rarely exceeds moderate AQI
- Portland, ME - Consistent good air
- San Diego, CA - Coastal air quality
- Honolulu, HI - Ocean breezes
Monitor Closely
- Los Angeles, CA - Summer ozone
- Phoenix, AZ - Summer dust and heat
- Salt Lake City, UT - Winter inversions
- Denver, CO - Seasonal variations
Frequently Asked Questions: Outdoor Events & Air Quality
What AQI is safe for an outdoor event?
AQI 0–50 is perfect for any outdoor event with no modifications, and 51–100 is still safe — just post the AQI, provide shaded rest areas and water, and alert sensitive groups. The safe ceiling depends on how active the event is: races, field days, and other active events are safe only up to about AQI 75; festivals, fairs, and outdoor markets up to 100; seated events like concerts, movies, and ceremonies up to 125 (minimal exertion but longer exposure); and children's events such as birthday parties up to 75, since kids are more vulnerable than adults. Above those limits, start modifying the event.
At what AQI should you cancel or move an outdoor event indoors?
From AQI 101–150, modify the event — shorten the duration by 30–50%, cut physical activities, add air-conditioned rest areas, offer N95 masks, and let attendees leave without penalty. At AQI 151–200, outdoor events are not recommended: move to an indoor venue if you can. At AQI 201 and above, do not hold outdoor gatherings at all — it is a serious health risk. Active events reach their cancel-or-modify point earliest (AQI 101), while seated ceremonies can usually proceed with caution to about AQI 150 before moving indoors.
Should an outdoor wedding be moved indoors because of air quality?
Check the AQI forecast in the week before the wedding and always contract an indoor backup — a tent with AC or an indoor venue. A seated ceremony can generally go ahead up to about AQI 125, but move indoors by AQI 151. An evening ceremony usually has better air than a hot afternoon (less ozone), and spring and fall are typically cleaner than summer. Communicate any air-quality concerns to elderly guests and anyone with respiratory or heart conditions, since they're the most vulnerable to smoke and ozone.
What is the best time of day and season to hold an outdoor event for clean air?
Schedule events for morning or evening when possible — ozone builds through hot afternoons and eases after sunset. By season, fall generally has the cleanest air and comfortable temperatures, spring is good (watch for pollen), and winter has low ozone but can trap pollution under inversions. Summer is the hardest: it's peak ozone season with the highest-AQI days, and on the West Coast wildfire season adds summer-into-fall variability. Graduations and other early-summer events benefit from evening scheduling and a shaded or indoor backup.
How should event organizers plan for poor air quality?
Build air quality into the plan before the event: check historical AQI for the date and location, avoid peak ozone months, contract an indoor backup venue, and include an air-quality cancellation clause. Set a clear AQI threshold for cancellation, create a way to notify attendees, and designate someone to monitor the AQI on the day — check it three hours before start and review the hourly forecast for the event's duration. Pick venues with better air (parks away from roads, waterfront, higher elevation) over highway-adjacent, industrial, or valley sites, post the current AQI at the entrance, and for multi-day festivals plan covered AC rest areas and consider partial refunds if air quality forces a cancellation.