Is the Air Quality Good in Hampshire, Massachusetts?
Yes — air quality in Hampshire, Massachusetts is good. The city earns an Air Quality Grade of B (good) on a 5-year median AQI of 39, which sits in the Good range, and logs only 6 unhealthy-air days over five years (about 1 per year). The general population can breathe outdoors safely on the vast majority of days.
Who Can Safely Breathe the Air in Hampshire, Massachusetts?
For most healthy adults, current air quality in this area does not require any change in behavior. People with severe asthma, COPD, or recent cardiac events should still keep an eye on daily AQI alerts, especially during wildfire season. Because ozone peaks in the afternoon on hot sunny days, plan outdoor exercise for early morning or after sunset on bad-air days.
Across the past five years, this area has logged just 6 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 1 days per year, or roughly one every other month. That is a low count by national standards.
Hampshire, Massachusetts Air Quality Snapshot
| Air Quality Grade | B67/100 |
| 5-Year Median AQI | 39 (Good) |
| Most Recent Median AQI (2023) | 38 (Good) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Stable (-0.18 AQI/yr) |
| Unhealthy Days (last 5 yr) | 6 |
| National Rank (cleanest = #1) | #419 of 1,020 (41th cleanest percentile) |
| Massachusetts Rank | #5 of 13 |
What Does the B Grade Mean?
Hampshire, Massachusetts earns a B — air quality is reliably in the safe range for most residents most of the time, with a 5-year median AQI of 39. Sensitive groups will see occasional caution days, but the typical resident will not need to change behavior based on air quality.
Hampshire, Massachusetts's 5-year median AQI of 39 is 2 points below the national average of 41 — meaningfully cleaner than the typical U.S. metro tracked here. Within Massachusetts, Hampshire, Massachusetts's air quality is roughly typical for the state, where the average city posts a 5-year median AQI of 41.
For context within Massachusetts: Suffolk, Massachusetts currently holds the state's cleanest grade (B, AQI 44), while Middlesex, Massachusetts sits at the bottom (C, AQI 39).
What's in Hampshire, Massachusetts's Air?
The dominant pollutant in Hampshire, Massachusetts is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle exhaust and industrial emissions. It is worst on hot, sunny, stagnant summer days. Ozone irritates the lungs, triggers asthma attacks, and reduces lung function — even healthy adults can feel chest tightness and shortness of breath after exercising in elevated ozone.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Ground-Level Ozone | 227 | 62% |
| Fine Particulate Matter (PM2.5) | 135 | 37% |
| Nitrogen Dioxide | 3 | 1% |
Is the Air Getting Better or Worse?
Air quality in Hampshire, Massachusetts has held roughly steady over the past decade, with year-to-year shifts in median AQI of less than half a point. That stability makes the city's long-run grade a reliable signal of what residents can expect day-to-day.
In 2014, Hampshire, Massachusetts posted a median AQI of 44. By 2023 that figure was 38 — a drop of 6 AQI points cleaner across 10 years of EPA records.
Year-by-Year AQI in Hampshire, Massachusetts
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 44 | 228 | 0 | PM2.5 |
| 2015 | 37 | 295 | 4 | Ozone |
| 2016 | 38 | 302 | 4 | Ozone |
| 2017 | 38 | 310 | 3 | Ozone |
| 2018 | 40 | 282 | 2 | Ozone |
| 2019 | 41 | 296 | 0 | Ozone |
| 2020 | 39 | 300 | 0 | PM2.5 |
| 2021 | 35 | 307 | 0 | Ozone |
| 2022 | 42 | 267 | 0 | Ozone |
| 2023 | 38 | 292 | 6 | Ozone |
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
More about Hampshire, Massachusetts
Hampshire, Massachusetts has an Air Quality Grade of B (good) with a 5-year median AQI of 39. The dominant pollutant is Ground-Level Ozone, and air quality has been stable over the past decade.
The data source behind this answer is the EPA Air Quality System (AQS). Every figure on the page traces back to that source; the methodology page describes the inputs and the refresh cadence in full detail.
A practical caveat: the headline answer above reflects the most recent the EPA Air Quality System (AQS) vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: EPA Outdoor Air Quality Data, 2026.