Jefferson County, Kentucky Air Quality
The nearest monitor to Jefferson County, at Cannons Lane, 3 miles away, measured an index of 26 at Mon, 9:00 AM EDT, which is Good for fine particles (PM2.5). Louisville Metro Air Pollution Control District forecasts Good for Louisville today and Moderate tomorrow.
- Measured now
- 26 · Good
- Today
- — · Good
- Tomorrow
- — · Moderate
- Pollutant
- PM2.5
Fine particles on the map
Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over Jefferson County, Kentucky. Open it for the live map, where it pans and zooms.
Open the live map with the particulate forecast
Map layer from NOAA National Air Quality Forecast Capability. Boundaries from the Iowa Environmental Mesonet.
Alerts in force
An Air Quality Alert is issued by the National Weather Service on behalf of a state or local agency when pollution is expected to reach a level that harms health. An Air Stagnation Advisory means the air will not move enough to clear what is already in it.
None are in force near Jefferson County right now. All Kentucky warnings.
Now
Good
- Nearest monitor
- Cannons Lane, 3 miles away (site 211110067)
- Index measured
- 26 · Good
- Measured at
- Mon, 9:00 AM EDT
- Fine particles
- 4.3 µg/m³
- Ozone
- 19 ppb
- Reporting area
- Louisville, KY, under a mile away
- Reported by
- Louisville Metro Air Pollution Control District
- Area index
- 28 · Good
Measured, not modeled. AirNow observations are preliminary until the operating agency certifies them, which happens months later.
Today and tomorrow
Louisville Metro Air Pollution Control District's own forecast for Louisville, written by a forecaster rather than read off a model.
| Day | Category | Index | Pollutant |
|---|---|---|---|
| Today | Good | PM2.5 | |
| Tomorrow | Moderate | PM2.5 | |
| Wednesday, September 23 | Moderate | PM2.5 |
The forecaster’s discussion
Written by Louisville Metro Air Pollution Control District for Louisville and filed with AirNow.
Southern Regions: Ozone was mostly Good, except for a couple Moderates across the state line around Louisville. As for PM2.5, it was mostly Moderate for the forecast period. (Past Friday through Sunday.) As of 12Z this morning, on the radar is a widespread area of showers and isolated thunderstorms mainly around I-70 and across portions of southern Indiana. This large body of precipitation is moving slowly east. Meanwhile, a stationary boundary is lingering to the south of Indiana, over Kentucky this morning and where it will remain today, before finally dropping south of Kentucky by this evening. Rain will eventually diminish throughout the day as the boundary drops farther south and conditions will become mostly cloudy. The southernmost counties of the area likely won't see much if any rain today, only a slight chance. Highs this afternoon will have quite the gradient ranging from the lower 70's (north) to the mid 80's (southern counties) of southern Indiana. Dew points will be in the upper 60's. Winds will be northerly at 5 to 10 mph. A weak wave moves across the area on Tuesday and could mean some isolated showers and thunderstorms. Seasonable temperatures will continue into tomorrow (Tuesday) and actually through the rest of the work week! Look for highs on Tuesday afternoon in the 70's with mostly cloudy skies. Dew points will be in the lower 60's. Winds will be northeast at 5 to 10 mph. Similar high temperatures and dew points are in store for Wednesday. Winds will continue to be from the northeast at 5 to 10 mph. As for guidance this forecast period, the Canadian is predicting Ozone to be Good through Wednesday. The 06Z BC NOAA model is also predicting Good ozone through Wednesday, which both models make sense as the area is getting a decent rain today, which may help clean out the area (at least over the northern counties of the area). Then the winds remain out of the northeast through the period at 5 to 10 mph, and it's hard to get Ozone growth with these kind of winds. Will therefore go with Good for ozone for the entire period for both sites, Evansville and Louisville. As for PM2.5, the NOAA model is predicting Good through Monday or Tuesday and then Moderate for Tuesday through Wednesday depending on which site you look at. (Louisville is a bit more robust with the Moderate.) Since the southernmost counties of the area will not get well cleaned due to a lack of rain, PM2.5 could start growing here as soon as Tuesday. So will be conservative and go with Good for today and then Moderate the rest of the period for PM2.5.
Hour by hour
NOAA’s National Air Quality Forecast Capability, bias-corrected against monitors, for this town’s own coordinate. The worst hour ahead is an index of 60, Moderate, around Wed, 7:00 AM EDT, from the run issued Mon, 2:00 AM EDT. This is a model, not a measurement.
| Hour | Index | Category | PM2.5 | Ozone |
|---|---|---|---|---|
| Mon, 4:00 AM EDT | 38 | Good | 5.7 | |
| Mon, 5:00 AM EDT | 33 | Good | 5.3 | |
| Mon, 6:00 AM EDT | 36 | Good | 7.2 | |
| Mon, 7:00 AM EDT | 30 | Good | 4.4 | |
| Mon, 8:00 AM EDT | 28 | Good | 4.9 | |
| Mon, 9:00 AM EDT | 29 | Good | 5.3 | |
| Mon, 10:00 AM EDT | 29 | Good | 5.3 | 27.6 |
| Mon, 11:00 AM EDT | 29 | Good | 5.4 | 29.7 |
| Mon, 12:00 PM EDT | 29 | Good | 5.5 | 31.9 |
| Mon, 1:00 PM EDT | 31 | Good | 5.7 | 33.9 |
| Mon, 2:00 PM EDT | 33 | Good | 5.5 | 36.1 |
| Mon, 3:00 PM EDT | 35 | Good | 5 | 38.5 |
| Mon, 4:00 PM EDT | 38 | Good | 4.9 | 41.4 |
| Mon, 5:00 PM EDT | 41 | Good | 5.8 | 44.1 |
| Mon, 6:00 PM EDT | 42 | Good | 5.6 | 45.9 |
| Mon, 7:00 PM EDT | 43 | Good | 7 | 46.6 |
| Mon, 8:00 PM EDT | 46 | Good | 10.3 | 46.8 |
| Mon, 9:00 PM EDT | 48 | Good | 9 | 46.4 |
| Mon, 10:00 PM EDT | 48 | Good | 8.9 | 45.1 |
| Mon, 11:00 PM EDT | 51 | Moderate | 10 | 42.7 |
| Tue, 12:00 AM EDT | 52 | Moderate | 9.5 | 39.8 |
| Tue, 1:00 AM EDT | 51 | Moderate | 9 | 36.4 |
| Tue, 2:00 AM EDT | 47 | Good | 8 | 33.2 |
| Tue, 3:00 AM EDT | 44 | Good | 7.2 | 30.3 |
| Tue, 4:00 AM EDT | 42 | Good | 7.3 | 27.3 |
| Tue, 5:00 AM EDT | 47 | Good | 9.5 | 24.2 |
| Tue, 6:00 AM EDT | 52 | Moderate | 11.1 | 21.1 |
| Tue, 7:00 AM EDT | 54 | Moderate | 12.2 | 18.1 |
| Tue, 8:00 AM EDT | 55 | Moderate | 12.3 | 15.5 |
| Tue, 9:00 AM EDT | 55 | Moderate | 11.5 | 14.1 |
| Tue, 10:00 AM EDT | 53 | Moderate | 8.2 | 13.4 |
| Tue, 11:00 AM EDT | 46 | Good | 6.4 | 13.2 |
| Tue, 12:00 PM EDT | 43 | Good | 7.1 | 13.4 |
| Tue, 1:00 PM EDT | 43 | Good | 8 | 14.6 |
| Tue, 2:00 PM EDT | 43 | Good | 7.6 | 16.7 |
| Tue, 3:00 PM EDT | 41 | Good | 7 | 20.2 |
| Tue, 4:00 PM EDT | 40 | Good | 7.1 | 23.6 |
| Tue, 5:00 PM EDT | 43 | Good | 8.4 | 26.3 |
| Tue, 6:00 PM EDT | 46 | Good | 9 | 28.1 |
| Tue, 7:00 PM EDT | 51 | Moderate | 10 | 29.1 |
| Tue, 8:00 PM EDT | 52 | Moderate | 10.7 | 29.5 |
| Tue, 9:00 PM EDT | 49 | Good | 7.8 | 29 |
| Tue, 10:00 PM EDT | 44 | Good | 6.9 | 28.1 |
| Tue, 11:00 PM EDT | 44 | Good | 7.7 | 26.6 |
| Wed, 12:00 AM EDT | 47 | Good | 9.6 | 24.7 |
| Wed, 1:00 AM EDT | 51 | Moderate | 10.3 | 22.7 |
| Wed, 2:00 AM EDT | 53 | Moderate | 11.3 | 20.4 |
| Wed, 3:00 AM EDT | 53 | Moderate | 10.9 | 18.5 |
| Wed, 4:00 AM EDT | 54 | Moderate | 11.4 | 17.2 |
| Wed, 5:00 AM EDT | 56 | Moderate | 12.5 | 15.9 |
| Wed, 6:00 AM EDT | 57 | Moderate | 12.8 | 14.6 |
| Wed, 7:00 AM EDT | 60 | Moderate | 15.7 | 12.5 |
| Wed, 8:00 AM EDT | 60 | Moderate | 13.7 | 11 |
| Wed, 9:00 AM EDT | 60 | Moderate | 13.7 | 10.1 |
| Wed, 10:00 AM EDT | 58 | Moderate | 12.3 | 9.9 |
| Wed, 11:00 AM EDT | 58 | Moderate | 12.3 | 10.3 |
| Wed, 12:00 PM EDT | 57 | Moderate | 11.7 | 11.3 |
| Wed, 1:00 PM EDT | 56 | Moderate | 11.2 | 12.9 |
| Wed, 2:00 PM EDT | 54 | Moderate | 9.4 | 14.8 |
| Wed, 3:00 PM EDT | 48 | Good | 7.1 | 17.2 |
| Wed, 4:00 PM EDT | 38 | Good | 5.1 | 19.5 |
| Wed, 5:00 PM EDT | 33 | Good | 4.9 | 21.4 |
| Wed, 6:00 PM EDT | 30 | Good | 5 | 22.9 |
| Wed, 7:00 PM EDT | 26 | Good | 3.9 | 23.6 |
| Wed, 8:00 PM EDT | 27 | Good | 5 | 23.1 |
| Wed, 9:00 PM EDT | 23 | Good | 3.5 | 22.2 |
| Wed, 10:00 PM EDT | 34 | Good | 8.1 | 21.1 |
| Wed, 11:00 PM EDT | 44 | Good | 10.1 | 20.3 |
| Thu, 12:00 AM EDT | 48 | Good | 9.3 | 19.9 |
| Thu, 1:00 AM EDT | 37 | Good | 4.8 | 20.8 |
| Thu, 2:00 AM EDT | 31 | Good | 4.3 | 21.4 |
Fine particles in micrograms per cubic meter, ozone in parts per billion as an 8-hour average. The index for each hour is EPA’s: the ozone figure is already the 8-hour average the ozone index is defined on, and the particle figure is run through EPA’s NowCast, which is how an hourly PM2.5 concentration becomes an index.
Smoke
NOAA’s analysts have not drawn smoke over Jefferson County in satellite imagery today.
NOAA’s model forecasts near-surface smoke peaking at 1.6 µg/m³ around Mon, 4:00 AM EDT.
What this means
Good
Air quality is satisfactory, and air pollution poses little or no risk.
- Who is affected
- Nobody is expected to be affected.
- What to do
- It is a good day to be outside.
- Index range
- 0 to 50
Category descriptions are the Environmental Protection Agency’s own.
What these numbers are. An index beside a monitor’s name is a measurement, published hourly by AirNow and preliminary until the operating agency certifies it. A category for today or tomorrow is a state or local agency forecaster’s own forecast for a reporting area. An hourly index is NOAA’s air quality model on a five-kilometer grid, not a reading from any instrument. Where a town has no monitor within reach, only the model figures appear, and the page says so.
Nearby
The nearest towns with a page of their own, closest first.
Weather forecast for Jefferson CountyWarnings in Jefferson CountyLive radar over Jefferson CountyKentucky air quality
Sources
Observations and daily forecasts from AirNow, the US Environmental Protection Agency’s program with NOAA, the National Park Service, NASA, tribal, state and local agencies. Hourly forecasts from NOAA’s National Air Quality Forecast Capability. Smoke analysis from NOAA’s Hazard Mapping System. Alerts from the National Weather Service. Index categories and breakpoints are EPA’s, as revised in 2024.