What Is the Air Quality in Jefferson, Tennessee?
Jefferson, Tennessee has an Air Quality Grade of B (good) with a 5-year median AQI of 41. The dominant pollutant is Ground-Level Ozone, and air quality has been improving over the past decade.
Jefferson, Tennessee Air Quality Snapshot
| Air Quality Grade | B69/100 |
| 5-Year Median AQI | 41 (Good) |
| Most Recent Median AQI (2023) | 42 (Good) |
| Dominant Pollutant | Ground-Level Ozone |
| 10-Year Trend | Improving (-0.52 AQI/yr) |
| Unhealthy Days (last 5 yr) | 2 |
| National Rank (cleanest = #1) | #553 of 1,020 (54th most polluted percentile) |
| Tennessee Rank | #16 of 23 |
What Does the B Grade Mean?
Jefferson, Tennessee 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 41. Sensitive groups will see occasional caution days, but the typical resident will not need to change behavior based on air quality.
Jefferson, Tennessee's 5-year median AQI of 41 is right around the national average of 41 across the 1,020 monitored U.S. cities tracked here. Within Tennessee, Jefferson, Tennessee's air quality is roughly typical for the state, where the average city posts a 5-year median AQI of 40.
For context within Tennessee: Roane, Tennessee currently holds the state's cleanest grade (A, AQI 36), while Hamilton, Tennessee sits at the bottom (C, AQI 49).
What's in Jefferson, Tennessee's Air?
The dominant pollutant in Jefferson, Tennessee 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 | 241 | 100% |
Is the Air Getting Better or Worse?
Air quality in Jefferson, Tennessee has been improving over the past decade, with median AQI dropping by roughly 0.5 points per year. That is consistent with the broader national pattern — most U.S. metros have seen steady reductions in particulate and ozone pollution since the 2010s as cleaner vehicles and power plants come online.
In 2014, Jefferson, Tennessee posted a median AQI of 44. By 2023 that figure was 42 — a drop of 2 AQI points cleaner across 10 years of EPA records.
Year-by-Year AQI in Jefferson, Tennessee
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 44 | 190 | 0 | Ozone |
| 2015 | 44 | 183 | 1 | Ozone |
| 2016 | 47 | 158 | 2 | Ozone |
| 2017 | 43 | 148 | 1 | Ozone |
| 2018 | 42 | 202 | 0 | Ozone |
| 2019 | 44 | 197 | 0 | Ozone |
| 2020 | 37 | 232 | 0 | Ozone |
| 2021 | 41 | 199 | 0 | Ozone |
| 2022 | 41 | 219 | 0 | Ozone |
| 2023 | 42 | 210 | 2 | Ozone |
Health Context for Jefferson, Tennessee
Across the past five years, this area has logged just 2 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 0 days per year, or roughly one every other month. That is a low count by national standards.
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.
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.
Jefferson, Tennessee has an Air Quality Grade of B (good) with a 5-year median AQI of 41. The dominant pollutant is Ground-Level Ozone, and air quality has been improving 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.