South Pasadena, 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.
South Pasadena, CA air quality summary: South Pasadena, CA, has a Clean Air Score of 39.6 and an overall grade of F. The city's average annual PM2.5 concentration is 13 µg/m³. South Pasadena has an annual PM2.5 mean of 13 µg/m³, which is considered elevated for long-term exposure. Long-term air quality in South Pasadena has been worsening over recent years.
Clean Air Score
A score of 39.6 and an F grade indicate that South Pasadena has elevated long-term exposure to fine particulate matter. This grade reflects environmental challenges typical of the San Gabriel Valley area.
🏡 What This Means for Buying
Air quality should be treated as one factor in a broader relocation or housing decision in South Pasadena. The city's data provides a baseline for evaluating long-term environmental conditions.
Indoor Air Quality in South Pasadena, 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 South Pasadena.
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 South Pasadena:
- 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 South Pasadena Homes:
🩺 My Health Risk Assessment
See how South Pasadena'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, South Pasadena's air quality worsened by 2.3 μg/m³. Based on NBER studies, this change correlates with a estimated 9.2% decrease in relative property value retention.
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Why South Pasadena earned a 39.6
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% | 67.2 |
| 5-Year Trend | 20% | 38.5 |
| Seasonal Variability | 10% | 80.8 |
| Extreme Events | 5% | 95 |
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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South Pasadena Air Quality FAQs
Is South Pasadena a good fit for people who care about long-term air quality?
South Pasadena, CA, has a Clean Air Score of 39.6 and a grade of F, indicating elevated particulate levels. Its annual PM2.5 mean of 13 µg/m³ is a relevant factor for long-term residents.
What is the frequency of unhealthy air days in South Pasadena?
South Pasadena reports an unhealthy air days percentage of 1.6%, which is reflected in its F grade. This frequency of spikes contributes to the overall annual particulate exposure.
Is the air quality in South Pasadena improving or getting worse over time?
The long-term air quality in South Pasadena is worsening according to recent historical trends. A 100% data completeness rate provides high confidence in this assessment of environmental change.
Does air quality vary across different parts of South Pasadena?
Air quality can vary within the city due to local traffic, industry, and location patterns. Factors like topography and proximity to major highways can influence local particulate concentrations.