Seacliff, California Air Quality
Seacliff has a median AQI of 37, earning an air quality grade of A — excellent air quality that ranks better than 74% of US cities. Air quality has remained relatively stable over the past decade. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Seacliff recorded 148 good air quality days (82% of monitored days).
Population: 3,299 • County: Santa Cruz
Current AQI
Quick Facts
| Current AQI | 8 — Good |
| Air Quality Grade | A |
| Median AQI (2025) | 37 |
| vs. U.S. Cities | Better than 74% |
| Primary Pollutant | Ozone |
| Unhealthy Days/Year | 0 |
| 10-Year Trend | → Stable |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Seacliff is sourced from the Santa Cruz AMS monitoring area, located approximately 4 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Wildfire smoke is a significant factor in Seacliff's air quality, with regional fires capable of pushing AQI from Good to Unhealthy within hours during fire season (typically July through October). On smoke-impacted days, staying indoors with windows closed and running an air purifier with a HEPA filter is the most effective protection.
AQI Trend (10 Years)
Air Quality Days by Year
Seacliff Median AQI by Year
Annual EPA air quality data for Seacliff — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 37 | 148 | — | 71 | Ozone |
| 2024 | 39 | 293 | — | 80 | PM2.5 |
| 2023 | 36 | 300 | 1 | 130 | PM2.5 |
| 2022 | 35 | 287 | — | 93 | PM2.5 |
| 2021 | 37 | 298 | — | 80 | Ozone |
| 2020 | 39 | 261 | 20 | 624 | PM2.5 |
| 2019 | 39 | 291 | — | 74 | PM2.5 |
| 2018 | 41 | 273 | 10 | 177 | PM2.5 |
| 2017 | 39 | 269 | 4 | 130 | PM2.5 |
| 2016 | 35 | 306 | — | 76 | PM2.5 |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About Seacliff Air Quality
What is the air quality in Seacliff today?
The current AQI in Seacliff is 8, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Seacliff getting better or worse?
Air quality in Seacliff has been stable. The median AQI has risen 2 points (from 35 in 2016 to 37 in 2025).
What is the most common air pollutant in Seacliff?
Ozone is the primary air pollutant in Seacliff, responsible for 98 days (54% of monitored days) in 2025. Ground-level ozone forms when sunlight reacts with emissions from vehicles and industry, typically peaking on hot summer afternoons.
How many unhealthy air days does Seacliff have per year?
In 2025, Seacliff recorded 82% good air quality days (148 days) out of 181 monitored days. There were 0 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 71.
What air quality grade does Seacliff receive?
Seacliff receives an air quality grade of A, placing it better than 74% of US cities. This is based on a median AQI of 37 in 2025, with 148 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 74% of US cities
Nearby Cities
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National Rankings
See how Seacliff compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Seacliff
Ozone is Seacliff's primary pollutant. Standard HEPA filters don't capture ozone molecules — you need activated carbon or PECO technology to chemically break them down. We highlight those units here.
Blueair Blue Pure 211+
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Other Great Options
Molekule Air Pro
Commercial-grade with patented PECO technology for destroying pollutants.
Honeywell HPA300
Powerful workhorse for large rooms. Built to last.
RabbitAir MinusA2
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Not sure which air purifier is right for you?
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