La Crescenta-Montrose, 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.
La Crescenta-Montrose, CA air quality summary: La Crescenta-Montrose, CA, has a Clean Air Score of 39.6 and a grade of F. The annual PM2.5 mean is 13, which is considered elevated for long-term exposure. La Crescenta-Montrose has an annual PM2.5 mean of 13, which is considered elevated for long-term exposure. Long-term air quality in La Crescenta-Montrose has been worsening over recent years.
Clean Air Score
A Clean Air Score of 39.6 and a grade of F indicate a significant level of long-term air pollution. These metrics reflect frequent and consistent exposure to fine particulate matter that exceeds recommended environmental levels.
🏡 What This Means for Buying
Prospective residents should carefully consider the elevated particulate levels as part of their long-term evaluation. Air quality should be treated as one factor in a broader relocation or housing decision.
Indoor Air Quality in La Crescenta-Montrose, 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 La Crescenta-Montrose.
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 La Crescenta-Montrose:
- 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 La Crescenta-Montrose Homes:
🩺 My Health Risk Assessment
See how La Crescenta-Montrose'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, La Crescenta-Montrose'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 La Crescenta-Montrose 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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La Crescenta-Montrose Air Quality FAQs
Is La Crescenta-Montrose a good fit for people who care about long-term air quality?
La Crescenta-Montrose presents challenges for those concerned with air quality, given its score of 39.6 and grade of F. The annual PM2.5 mean of 13 represents an elevated level of long-term exposure.
What is the frequency of unhealthy air or long-term pollution exposure in La Crescenta-Montrose?
La Crescenta-Montrose experiences unhealthy air on 1.6% of days, contributing to its F grade. This indicates that residents face regular periods of exposure to pollution levels that exceed health standards.
Is air quality in La Crescenta-Montrose improving or getting worse over time?
The air quality in La Crescenta-Montrose has been worsening over recent years. This suggests that long-term pollution levels are on an upward trajectory.
Does air quality vary within different parts of La Crescenta-Montrose?
Air quality can vary within the city due to local traffic, industry, and location patterns. Topography and proximity to major transit corridors can significantly affect local air conditions.