Colorado air quality

Louisville, Colorado Air Quality

Boulder County39.978, -105.132

The nearest monitor to Louisville, at Rocky Flats - N - 16600 W. Colo. Hwy. 128, 5 miles away, measured an index of 50 at Mon, 6:00 PM MDT, which is Good for ground-level ozone. Colorado Department of Public Health and Environment forecasts Moderate for Denver-Boulder today and Moderate tomorrow.

Measured now
50 · Good
Today
— · Moderate
Tomorrow
— · Moderate
Pollutant
Ozone

Fine particles on the map

Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over Louisville, Colorado. Open it for the live map, where it pans and zooms.

Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over Louisville, Colorado 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 Louisville right now. All Colorado warnings.

Now

Good

Nearest monitor
Rocky Flats - N - 16600 W. Colo. Hwy. 128, 5 miles away (site 080590006)
Index measured
50 · Good
Measured at
Mon, 6:00 PM MDT
Ozone
59 ppb
Reporting area
Denver-Boulder, CO, 7 miles away
Reported by
Colorado Department of Public Health and Environment
Area index
61 · Moderate

Measured, not modeled. AirNow observations are preliminary until the operating agency certifies them, which happens months later.

Today and tomorrow

Colorado Department of Public Health and Environment's own forecast for Denver-Boulder, written by a forecaster rather than read off a model.

DayCategoryIndexPollutant
TodayModerateOzone
TomorrowModeratePM2.5

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 50, Good, around Tue, 7:00 PM MDT, from the run issued Mon, 6:00 AM MDT. This is a model, not a measurement.

HourIndexCategoryPM2.5Ozone
Mon, 8:00 AM MDT42Good8.5
Mon, 9:00 AM MDT46Good9.1
Mon, 10:00 AM MDT45Good8
Mon, 11:00 AM MDT42Good6.7
Mon, 12:00 PM MDT42Good7.6
Mon, 1:00 PM MDT41Good6.9
Mon, 2:00 PM MDT38Good635.1
Mon, 3:00 PM MDT36Good5.239.3
Mon, 4:00 PM MDT40Good443.9
Mon, 5:00 PM MDT44Good3.148.4
Mon, 6:00 PM MDT47Good251.6
Mon, 7:00 PM MDT49Good0.653.1
Mon, 8:00 PM MDT48Good1.852.2
Mon, 9:00 PM MDT45Good2.649.5
Mon, 10:00 PM MDT43Good1.946.1
Mon, 11:00 PM MDT39Good0.542.6
Tue, 12:00 AM MDT35Good0.838.5
Tue, 1:00 AM MDT31Good0.434.4
Tue, 2:00 AM MDT28Good0.630.7
Tue, 3:00 AM MDT26Good128.3
Tue, 4:00 AM MDT25Good0.927.3
Tue, 5:00 AM MDT25Good1.727
Tue, 6:00 AM MDT24Good2.226.5
Tue, 7:00 AM MDT23Good1.925.2
Tue, 8:00 AM MDT21Good3.323.8
Tue, 9:00 AM MDT20Good3.522.8
Tue, 10:00 AM MDT20Good3.823
Tue, 11:00 AM MDT22Good4.523.8
Tue, 12:00 PM MDT26Good5.325.5
Tue, 1:00 PM MDT30Good6.328.3
Tue, 2:00 PM MDT30Good5.532.1
Tue, 3:00 PM MDT34Good4.737.4
Tue, 4:00 PM MDT40Good3.243.4
Tue, 5:00 PM MDT44Good248.9
Tue, 6:00 PM MDT48Good2.252.6
Tue, 7:00 PM MDT50Good3.154.4
Tue, 8:00 PM MDT49Good454
Tue, 9:00 PM MDT48Good2.252.9
Tue, 10:00 PM MDT46Good0.950.9
Tue, 11:00 PM MDT43Good0.946.9
Wed, 12:00 AM MDT39Good0.942.4
Wed, 1:00 AM MDT35Good0.738.2
Wed, 2:00 AM MDT31Good0.734.8
Wed, 3:00 AM MDT30Good0.732.1
Wed, 4:00 AM MDT28Good0.830.6
Wed, 5:00 AM MDT26Good0.828.5
Wed, 6:00 AM MDT24Good0.626.4
Wed, 7:00 AM MDT22Good0.824.9
Wed, 8:00 AM MDT20Good1.323
Wed, 9:00 AM MDT19Good1.321
Wed, 10:00 AM MDT18Good1.519.9
Wed, 11:00 AM MDT18Good2.719.6
Wed, 12:00 PM MDT19Good320.4
Wed, 1:00 PM MDT19Good3.721.8
Wed, 2:00 PM MDT21Good2.523.7
Wed, 3:00 PM MDT24Good0.126.1
Wed, 4:00 PM MDT27Good0.429.1
Wed, 5:00 PM MDT29Good0.431.5
Wed, 6:00 PM MDT31Good0.333.1
Wed, 7:00 PM MDT31Good0.234
Wed, 8:00 PM MDT31Good1.234
Wed, 9:00 PM MDT31Good2.333.3
Wed, 10:00 PM MDT29Good0.831.9
Wed, 11:00 PM MDT28Good0.830.7
Thu, 12:00 AM MDT27Good0.429.8
Thu, 1:00 AM MDT27Good0.329.1
Thu, 2:00 AM MDT26Good0.928.2
Thu, 3:00 AM MDT25Good1.327.3
Thu, 4:00 AM MDT24Good0.426.7
Thu, 5:00 AM MDT23Good0.625.9
Thu, 6:00 AM MDT22Good0.624.9

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 Louisville in satellite imagery today.

NOAA’s model forecasts near-surface smoke peaking at 0.7 µg/m³ around Mon, 2:00 AM MDT.

Smoke on the radar over Louisville

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 LouisvilleWarnings in Boulder CountyLive radar over LouisvilleColorado 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.