San Dimas, CA
Long-term air quality
What this page tells you
This page combines annual PM2.5, unhealthy days, 5-year trend, and data coverage so you can compare long-term air quality, not just today's reading.
San Dimas, CA air quality summary: San Dimas, CA receives a clean air score of 30.7 and a grade of F, reflecting significant long-term air quality challenges. The city's annual mean PM2.5 concentration is 14.7 µg/m³. The annual mean concentration of PM2.5 in San Dimas is 14.7 µg/m³. Long-term air quality in San Dimas has remained neutral over recent years.
Clean Air Score
A clean air score of 30.7 and a grade of F signify that San Dimas experiences high long-term exposure to particulate matter. These ratings indicate poor environmental conditions for long-term residency.
🏡 What This Means for Buying
San Dimas' air quality should be a primary consideration for anyone evaluating long-term living conditions. The F grade reflects a level of particulate matter that is elevated by national standards.
Indoor Air Quality in San Dimas, CA
Outdoor pollution can still affect indoor air when windows are open, filtration is weak, or wildfire smoke moves in.
How to react when today's AQI changes
Use the AQI bands below to decide whether to open windows, run an air purifier, or stay indoors when pollution spikes in San Dimas.
AQI 0-50
GoodOpen windows: Open windows if you want fresh air.
Air purifier: No purifier needed for most homes.
Indoor activity: Normal indoor activity is fine.
AQI 51-100
ModerateOpen windows: Sensitive groups should limit open-window time.
Air purifier: Use fans or filtration if dust or pollen is bothering you.
Indoor activity: Most people can stay active indoors.
AQI 101-150
Unhealthy for Sensitive GroupsOpen windows: Keep windows closed.
Air purifier: Run a HEPA purifier in the main room and bedroom.
Indoor activity: Sensitive groups should reduce outdoor exposure.
AQI 151+
UnhealthyOpen windows: Keep windows and doors closed.
Air purifier: Run HEPA continuously and seal obvious drafts.
Indoor activity: Stay indoors as much as possible; use an N95 if you must go out.
Common indoor air concerns in San Dimas:
- Wildfire smoke infiltration (PM2.5)
- Seasonal pollen and dust mite allergens
- VOCs from household products
Recommended action: If today's AQI reaches 101 or higher, close windows and run HEPA filtration before indoor air starts to feel smoky or stale.
Top Products for San Dimas Homes:
🩺 My Health Risk Assessment
See how San Dimas's air quality affects you and your family specifically.
Health Advice
Reduce prolonged outdoor exertion.
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</> Create Free Widget🏡 Property Value Impact Analysis
Between 2019 and 2024, San Dimas's air quality worsened by 0.1 μg/m³. Based on NBER studies, this change correlates with a estimated 0.4% decrease in relative property value retention.
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Why San Dimas earned a 30.7
Raw inputs, scoring weights, and data coverage for this city.
Best Time to Run
Find the cleanest hours for your run today.
Cycling Forecast
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📅 Past 30 Days Trend
Real-time daily PM2.5 AQI
🌸 Pollen Outlook
Current Seasonal Forecast
How it worksBased on current seasonal forecast data. Not a long-term pollution rating or relocation score.
Score Breakdown
| Component | Weight | Score Contribution |
|---|---|---|
| Annual Air Quality | 40% | 0 |
| Unhealthy Days | 25% | 34.2 |
| 5-Year Trend | 20% | 50 |
| Seasonal Variability | 10% | 76.6 |
| Extreme Events | 5% | 90 |
Explore More Air Quality Data
Frequently Asked Questions
About This Data
Data Sources
Historical air quality mapping and scoring are based completely on official U.S. Environmental Protection Agency (EPA) AirNow API data. 5-day AQI forecasts are provided by WAQI.
Methodology
Our Clean Air Score (0-100) is a proprietary algorithm that weighs multiple factors:
- Annual PM2.5 averages (40%)
- Frequency of unhealthy days (25%)
- 5-year pollution trends (20%)
- Seasonal variability and extreme events (15%)
Updates & Accuracy
Real-time data is updated hourly. Historical aggregate scores are recalculated monthly to reflect the latest trends. While we strive for accuracy, sensor maintenance and local conditions can affect individual readings.
Practical Advice
When AQI > 100: Sensitive groups (children, elderly, asthmatics) should limit prolonged outdoor exertion.
When AQI > 150: Everyone should avoid outdoor exercise and keep windows closed.
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San Dimas Air Quality FAQs
Is San Dimas a good fit for people who care about long-term air quality?
San Dimas' clean air score of 30.7 and grade of F indicate very high long-term particulate exposure. The annual PM2.5 mean of 14.7 µg/m³ is considered elevated for long-term health considerations.
How frequent is unhealthy air in San Dimas?
In San Dimas, 3.3% of days are classified as unhealthy, reflecting its F grade and PM2.5 mean of 14.7 µg/m³. Residents face more frequent exposure to pollution than in most other cities.
Is air quality in San Dimas improving or getting worse over time?
The long-term air quality trend in San Dimas is described as neutral, suggesting limited change in recent years.
Does air quality vary within San Dimas?
Air quality can vary within the city due to local traffic, industry, and location patterns, without naming specific districts.