Herndon, VA
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.
Herndon, VA air quality summary: Herndon, VA is currently rated with a Clean Air Score of 79.4 and a grade of B, with an annual PM2.5 mean of 6.8 µg/m³. This data summarizes the city's long-term atmospheric conditions based on historical records. Herndon records an annual PM2.5 mean of 6.8 µg/m³, which is considered moderate for long-term exposure. Historical records show that long-term air quality in Herndon has been improving over recent years.
Clean Air Score
The Clean Air Score of 79.4 and B grade indicate moderate long-term air quality in Herndon. This assessment evaluates chronic environmental exposure over multi-year periods.
🏡 What This Means for Buying
Evaluated air quality in Herndon is one element of a broad long-term living assessment. The B grade serves as a factual context for those considering relocation to the area.
Indoor Air Quality in Herndon, VA
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 Herndon.
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 Herndon:
- 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 Herndon Homes:
🩺 My Health Risk Assessment
See how Herndon's air quality affects you and your family specifically.
Health Advice
Enjoy the outdoors! Air quality is great.
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</> Create Free Widget🏡 Property Value Impact Analysis
Between 2019 and 2024, Herndon's air quality improved by 2.4 μg/m³. Based on NBER studies, this change correlates with a estimated 9.6% increase in relative property value retention.
Cleaner Alternatives in VA
Why Herndon earned a 79.4
Raw inputs, scoring weights, and data coverage for this city.
Best Time to Run
Find the cleanest hours for your run today.
Cycling Forecast
Avoid pollution spikes on your next ride.
📅 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% | 74.8 |
| Unhealthy Days | 25% | 100 |
| 5-Year Trend | 20% | 62 |
| Seasonal Variability | 10% | 94.5 |
| Extreme Events | 5% | 100 |
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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Herndon Air Quality FAQs
Is Herndon a good fit for people who care about long-term air quality?
Herndon, VA holds a Clean Air Score of 79.4 and a grade of B, with an annual PM2.5 mean of 6.8 µg/m³. This profile reflects moderate long-term air quality baseline for residents.
How often does Herndon experience unhealthy air frequency?
In Herndon, 0% of days recorded unhealthy air levels, consistent with its B grade and 6.8 µg/m³ annual PM2.5 mean. This suggests that acute pollution spikes are rare in the historical record.
Is the air quality in Herndon improving or getting worse over time?
Long-term monitoring in Herndon suggests that air quality has been improving over recent years.
Does air quality vary within Herndon?
Air quality can fluctuate within Herndon due to local factors like traffic and development, which is typical for many urban environments.