EPA ACTIVE WATCH Western US & Intermountain Basins: Wildfire Smoke & Elevated PM2.5 Infiltration

Chelsea air quality.

Air quality observations and historical context for Chelsea, MA

Historical perspective

The longer view.

Annual PM2.5 concentrations · µg/m³

Historical annual PM2.5 concentrations 0.04.89.5 2020: 9.5 µg/m³20202021: 7 µg/m³20212022: 6.5 µg/m³20222023: 7.5 µg/m³20232024: 6 µg/m³2024
View data table
Annual PM2.5 · µg/m³
YearPM2.5
20209.5
20217.0
20226.5
20237.5
20246.0
Historical score83.2/100
Annual mean PM2.56.0 µg/m³

Available history: 2020–2024. Historical scores are distinct from current AQI and do not describe today’s conditions.

Sources and scoring method ↗

Local context

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.

Sponsor
83.2
Clean Air Score
Chelsea Long-term Air Quality
Based on EPA 5-year data · Loading live AQI...
Connecting to live sensor...

Regional Air Quality Context & Seasonal Patterns

Chelsea is treated as a local community in MA, so the most useful signal is the long-term pollution baseline rather than a single live AQI reading. Annual PM2.5 averages 6 ug/m3, with roughly 0 unhealthy-air days per year, and the multi-year trend is improving. Its Clean Air Score is 83.2 (grade B), which helps compare Chelsea with other MA cities. In Chelsea, historical EPA observations show that pollution levels typically peak in July (averaging an index of 44), while the cleanest air conditions occur in November (averaging 23). With an extreme events rating of 100/100, Chelsea exhibits resilient atmospheric ventilation with fewer multi-day smoke outliers. This report uses direct city-level monitor coverage where available, so the trend is tied closely to conditions in Chelsea.

Peak Season
July Peak

Summer (Photochemical ozone & warm-season haze)

Cleanest Air Window
November

Historically lowest pollution baseline

Sensitive Groups Guidance
Sensitive groups and outdoor runners should prioritize early morning activity before midday heat and ground-level ozone accelerate.

Fine particulate matter (PM2.5) in Chelsea is monitored for health safety. Long-term exposure to pollutants can lead to respiratory issues, making daily checks essential for active residents in MA.

Clean Air Getaways & Cleaner Alternatives

Looking for cleaner air near Chelsea?

These destinations have significantly higher historical Clean Air Scores than Chelsea (Score: 83.2).

View All Clean Air Rankings →
82 mi away +6.1 pts higher

Chicopee, MA

89.3 / 100 Clean Air Score
81 mi away +6.1 pts higher

North Chicopee, MA

89.3 / 100 Clean Air Score
90 mi away +6.1 pts higher

Westfield, MA

89.3 / 100 Clean Air Score

Indoor Air Quality in Chelsea, MA

Outdoor pollution can still affect indoor air when windows are open, filtration is weak, or wildfire smoke moves in.

Complete Chelsea Home AQI & Filtration Guide

Get custom room-by-room HEPA purifier sizing, seasonal PM2.5 trends, and local home sealing recommendations.

👉 Read Full Chelsea Guide →
AQI 0-50: Good
Windows

Usually safe to open windows for fresh air.

Air Purifier

Air purifier is optional for most households.

Stay Indoors

Normal indoor and outdoor activity is fine.

AQI 51-100: Moderate
Windows

Ventilate selectively; sensitive groups should watch symptoms.

Air Purifier

Run HEPA filtration on low if pollen, smoke smell, or traffic exhaust is noticeable.

Stay Indoors

Most people can continue normal activity; sensitive groups should keep an eye on AQI.

AQI 101-150: Unhealthy for sensitive groups
Windows

Keep windows closed so outdoor PM2.5 does not build indoors.

Air Purifier

Run HEPA filtration in bedrooms and main living spaces.

Stay Indoors

Children, older adults, and people with asthma should reduce outdoor exertion.

AQI 151+: Unhealthy
Windows

Keep windows and doors sealed as much as practical.

Air Purifier

Run filtration continuously; use the highest comfortable fan setting.

Stay Indoors

Stay indoors when possible and consider an N95 if you must go outside.

Health Recommendations

General Public

Most people can continue outdoor activities normally. Keep an eye on changing conditions.

Sensitive Groups

Children and elderly should reduce prolonged or heavy outdoor exertion if AQI rises above 50.

Running & Outdoor Exercise Guide

Explore available hourly data before planning outdoor time in Chelsea.

🏃 View Running Forecast →
SISTER RESEARCH INITIATIVE
WATERQ.US × CLEANAIRDATA

Environmental Health Dossier: Air & Tap Water in Chelsea

Atmospheric fine particulate matter (PM2.5) and municipal drinking water contaminants represent the two primary involuntary daily exposures in any household. While HEPA filtration purifies indoor air, municipal tap water often contains invisible halogenated byproducts, heavy metals, or PFAS forever chemicals.

Atmospheric Exposure
Inhalation Risk

Chelsea holds a historical Clean Air Score of 83.2/100. High PM2.5 requires True HEPA (H13) physical media filters without electronic ozone generation.

Hydrological Exposure
Ingestion Risk

Municipal utility compliance focuses on legal limits, not health guidelines. Verified solid-carbon or Reverse Osmosis filters target lead, chlorine byproducts, and micropollutants.

Review EPA Safe Drinking Water Information System (SDWIS) utility compliance reports.
Inspect Chelsea Tap Water on WaterQ.us
Head-to-Head Benchmark

Compare Chelsea Air Quality

See how Chelsea’s pollution baselines and seasonal patterns compare side-by-side.

Custom City Matchup →
Webmaster & Community Resource

Embed Chelsea Live Air Quality on Your Website

Free for local blogs, schools, news portals, outdoor clubs, and community hubs. Displays real-time AQI with zero maintenance required.

Customize Styling →
HTML Embed Snippet
<iframe src="https://cleanairdata.org/widget/city/chelsea-ma" width="300" height="220" style="border:0;border-radius:16px;overflow:hidden;" loading="lazy" title="Chelsea Real-Time Air Quality"></iframe>
<p style="font-size:11px;color:#64748b;margin-top:4px;"><a href="https://cleanairdata.org/city/chelsea-ma" target="_blank" rel="noopener">Chelsea Air Quality Data</a> by CleanAirData.org</p>
Sponsor

Frequently Asked Questions about Chelsea Air Quality

Is air quality in Chelsea safe today?

Current air quality in Chelsea is being monitored. Based on historical data, Chelsea has a clean air score of 83.2. For real-time updates, check the live monitoring panel on this page.

When is air pollution highest in Chelsea?

According to multi-year EPA observations, air pollution in Chelsea historically peaks during July (Summer (Photochemical ozone & warm-season haze)). The cleanest air window typically occurs in November.

What should sensitive groups do during peak air pollution in Chelsea?

Sensitive groups and outdoor runners should prioritize early morning activity before midday heat and ground-level ozone accelerate. Maintaining certified indoor HEPA filtration is an effective way to minimize personal exposure.

What is a dangerous AQI level?

An AQI (Air Quality Index) above 100 is considered unhealthy for sensitive groups, while levels above 150 are unhealthy for everyone. Levels above 300 are hazardous.

Should I wear a mask today in Chelsea?

If the AQI in Chelsea is above 150, an N95 mask is recommended for outdoor activities to filter out fine particulate matter (PM2.5).

Free Live Embed

Chelsea AQI Widget

Display real-time air quality on your local school portal, news site, or club blog.

Get Custom Embed Code →