Signal Mountain, Tennessee Air Quality

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.

• Air Quality Alert Air Quality Alert issued September 21 at 4:48PM CDT by NWS Memphis TNCrittenden; DeSoto; Shelby
  Full text

  AQAMEG The Shelby County Health Department has issued a Code Orange Ozone Health Advisory effective for Shelby County Tennessee, Crittenden County Arkansas, and DeSoto County Mississippi, including the city of Memphis that will remain in effect until sunset. This ozone health advisory is due to monitored ozone values that are unhealthy for sensitive groups. These values have exceeded the Environmental Protection Agency's federal safe health standard. The Shelby County Health Department recommends that sensitive groups which include active children and adults, and people with respiratory disease, such as asthma, limit prolonged outdoor exertion. Please continue to check the latest air quality forecasts and updates until monitored values return to safe levels. For more information go to www.airnow.gov.

All Tennessee warnings

Moderate

Nearest monitor

Siskin Dr, 6 miles away (site 470654002)

Index measured

57 · Moderate

Measured at

Mon, 5:00 PM EDT

Fine particles

10.5 µg/m³

Reporting area

Chattanooga, TN, 5 miles away

Reported by

Tennessee Air Pollution Control Div.

Area index

59 · Moderate

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

Tennessee Air Pollution Control Div.'s own forecast for Chattanooga, written by a forecaster rather than read off a model.

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 55, Moderate, around Mon, 5:00 PM EDT, from the run issued Mon, 8:00 AM EDT. This is a model, not a measurement.

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.

NOAA’s Hazard Mapping System analysts drew medium smoke over Signal Mountain in satellite imagery today (Mon, 8:00 AM EDT to Mon, 11:00 AM EDT). That is smoke seen from above; it is not always smoke at ground level.

NOAA’s model forecasts near-surface smoke peaking at 1.7 µg/m³ around Tue, 5:00 AM EDT.

Smoke on the radar over Signal Mountain

Moderate

Air quality is acceptable. There may be a risk for some people, particularly those who are unusually sensitive to air pollution.

Who is affected

People who are unusually sensitive to ozone or fine particles.

What to do

If you are unusually sensitive, consider making long or intense outdoor activity shorter or easier.

Index range

51 to 100

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.

The nearest towns with a page of their own, closest first.

• Red Bank, TN3 miles
• Walden, TN4 miles
• Fairmount, TN4 miles
• Lone Oak, TN6 miles
• Chattanooga, TN6 miles
• East Chattanooga, TN7 miles
• Falling Water, TN8 miles
• Lookout Mountain, TN9 miles

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.