Highlights
- The Fountain Hills air monitor recorded ozone at 71.0 ppb at 11 p.m. Wednesday, July 16, crossing the Unhealthy for Sensitive Groups threshold.
- The reading comes from AQS site 040139704, reported by the Maricopa County Air Quality Department via EPA AirNow.
- Residents in sensitive groups should check the AirNow Phoenix-area page for current forecasts and any active advisories.
The Maricopa County Air Quality Department reported an ozone reading of 71.0 parts per billion at the Fountain Hills monitoring station (AQS site 040139704) at 11 p.m. Wednesday, July 16, according to the EPA AirNow public hourly aggregate. That level crosses AirNow's Unhealthy for Sensitive Groups breakpoint for ozone.
The reading was published through the EPA AirNow system, which aggregates hourly data from Maricopa County's network of air quality monitors. Sensitive groups, which the Arizona Department of Environmental Quality identifies as children, older adults, adults exercising outdoors, and people with heart or lung disease, asthma, or bronchitis, face elevated risk at this concentration level, according to ADEQ's Phoenix forecast page.
For guidance specific to Maricopa County, residents can contact the Maricopa County Air Quality Department at 602-506-6010 or visit the county's air quality page. The AirNow Phoenix-area forecast carries the current advisory status and hourly updates.
Sources
Every factual claim in this article traces to one of the sources below. See how we work for the editorial process.
- 040139704 retrieved 17/07/2026 00:19
- azdeq.gov retrieved 17/07/2026 00:19
- fountainhillsaz.gov retrieved 17/07/2026 00:19
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 17/07/2026 00:19. Every claim traces to a source.
