Highlights
- The West Phoenix air monitor recorded ozone at 77.0 PPB at midnight July 23, crossing AirNow's Unhealthy for Sensitive Groups breakpoint.
- Carbon monoxide, nitrogen dioxide, PM10, and PM2.5 readings at the same station remained well below alert thresholds at the same hour.
- Maricopa County Air Quality Department is the reporting agency; current Phoenix-area conditions and forecasts are available via AirNow.
The West Phoenix air monitoring station (AQS site ID 040130019) recorded ozone at 77.0 parts per billion at midnight Thursday, crossing AirNow's threshold for the Unhealthy for Sensitive Groups category, according to EPA AirNow hourly aggregate data reported by the Maricopa County Air Quality Department.
Other pollutants at the station during the same hour remained low: carbon monoxide at 0.1 PPM, nitrogen dioxide at 3.0 PPB, PM10 at 5.0 micrograms per cubic meter, and PM2.5 at 0.7 micrograms per cubic meter.
The Maricopa County Air Quality Department operates a Rapid Response Notification System for residents who want alerts when pollution levels rise at selected monitoring locations across the valley, including a West 43rd Avenue station at 43rd Avenue and Broadway Road. Sign-up information is available through the county. For current Phoenix-area ozone forecasts and any active advisories, the EPA's AirNow Phoenix page is updated hourly. Health guidance, if issued, would come from Maricopa County Air Quality.
Sources
Every factual claim in this article traces to one of the sources below. See how we work for the editorial process.
- 040130019 retrieved 23/07/2026 01:17
- Maricopa County retrieved 23/07/2026 01:17
Authored by The Scottsdale Signal. Drafted by AI from primary-source material under our beat-specific editorial guides; reviewed by humans before publish under our five-gate process. Sources retrieved at 23/07/2026 01:17. Every claim traces to a source.
