Air quality monitoring for outdoor events is the signal weather alone can't tell you. A sunny, 75°F afternoon at Coachella in 2020 had an AQI over 200 from wildfire smoke 90 miles upwind — the kind of reading that gets festivals postponed, performers' insurance riders triggered, and N95 masks distributed to crowd-facing staff. SignalGuard's air quality signal surfaces the same EPA AQI bands that local public health agencies use, plus the 24-hour forecast so you know whether the haze rolls in during ingress or after the headliner.
What this signal monitors
The Air Quality signal reports the current US AQI at the venue, the dominant pollutant pushing the number up (PM2.5, PM10, ozone, NO₂, SO₂, or carbon monoxide), and the worst AQI projected in the next 24 hours. It covers wildfire smoke, ozone alerts, dust storms, inversion-trapped smog, and industrial releases — anything that degrades breathable air for crowds, staff, or performers.
Data sources
SignalGuard's airQualityClient.js calls the Open-Meteo Air Quality API, which blends ECMWF/CAMS atmospheric models with ground-station observations into a single global feed. No API key, no rate limit at our usage level, and global coverage. We request the current snapshot plus hourly forecasts for the next 48 hours, then bucket every 3 hours into an 8-cell strip the UI renders as the "next 24h" sparkline. AQI is reported on the US EPA scale, the same one AirNow.gov and state environmental agencies publish.
How SignalGuard scores severity
US AQI bands map directly to our threat scale: 0–100 is low (Good or Moderate); 101–150 is medium (Unhealthy for Sensitive Groups); 151–300 is high (Unhealthy through Very Unhealthy); 301+ is critical (Hazardous). The signal also looks 24 hours ahead — if the current AQI is 90 but the peak in the next 24 hours is 175, the threat level escalates to high so the operator sees what's coming. SignalGuard separately surfaces the dominant pollutant — the one whose concentration is furthest above its EPA moderate-band ceiling — because the operational response differs sharply: PM2.5 from wildfire smoke calls for N95s and indoor staging; ozone calls for strenuous-activity advisories; dust calls for filter changes on HVAC at indoor sub-venues.
Use cases for event security
- Wildfire smoke ingress decision. When the current AQI is Moderate but the 24-hour peak forecast lands in the Unhealthy band, operations briefs medical and pre-positions masks for crowd-facing staff before gates open.
- Outdoor staffing duration limits. Sustained AQI above 150 triggers rotation of perimeter security and parking attendants to indoor breaks every 60 minutes — guidance from EPA's outdoor worker advisory.
- Performer rider compliance. Many touring acts contract specific air quality ceilings (typically AQI 150 as a hard stop). The 24-hour forecast lets production tell management before they board the plane, not after soundcheck.
Pairs well with
- Wildfire smoke monitoring — the smoke source that explains a rising PM2.5 reading.
- Weather monitoring — wind direction and speed determine whether the smoke clears or settles.
- SPC severe weather forecasts — convective activity often clears or worsens air quality dramatically.
Premium upgrade path
For higher-resolution sensor data, BYOK an IQAir AirVisual API key on the Integrations page — IQAir's network includes consumer-grade and reference-grade ground stations that report at sub-hourly cadence, which matters when smoke is rolling in fast. BreezoMeter (now part of Google) and PurpleAir are also supported as BYOK providers. For US-only events near EPA-monitored cities, the free Open-Meteo path is operationally sufficient.
Frequently asked questions
What AQI level should cancel an outdoor event? The EPA recommends sensitive groups limit prolonged exertion at AQI 101+ and that everyone reduce exertion at 151+. Most production safety officers treat sustained AQI 200+ as a postponement threshold and AQI 300+ as a hard stop.
Does the signal track wildfire smoke specifically? Yes — wildfire smoke is dominated by PM2.5, and SignalGuard surfaces the dominant pollutant alongside the headline AQI. Pair this signal with Wildfire smoke monitoring for hotspot geometry.
How accurate is air quality for venues without a nearby ground station? Open-Meteo's model fills sensor gaps with ECMWF/CAMS atmospheric data, which is accurate to within roughly 10 AQI points for unhealthy events but smooths out very localized spikes. BYOK IQAir for higher-density sensor coverage.
Does air quality monitoring work outside the US? Yes — Open-Meteo is global. The US AQI band labels still apply; SignalGuard also reports the European AQI alongside for reference.
Can I set an AQI threshold to alert my team? Yes — Pro and Enterprise plans support custom thresholds. See the Integrations page and docs hub.
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