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New Hampshire Air Quality

Coastal Rockingham County is the worst air in New Hampshire right now at an index of 27, which is Good, from ground-level ozone. AirNow carries 11 reporting areas in the state. No air quality alert is in force.

Reporting areas
11
Worst index now
27
Alerts in force
0
Towns under smoke
Unavailable

Fine particles on the map

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

Forecast fine particulate matter from NOAA’s National Air Quality Forecast Capability over New Hampshire 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 in New Hampshire right now. All New Hampshire warnings.

By city, now and the days ahead11

Every AirNow reporting area in New Hampshire: what its monitors measured this hour, and what the state or local agency that forecasts for it expects today and tomorrow. Each area links to the nearest town’s page.

Reporting areaNowCategory nowTodayTomorrowPollutant
Coastal Rockingham County27GoodGoodGoodOzone
Coos County24GoodGoodGoodOzone
Hillsborough County24GoodGoodGoodOzone
Interior Rockingham County21GoodGoodGoodPM2.5
Cheshire County18GoodGoodGoodPM2.5
Belknap County17GoodGoodGoodOzone
Grafton County17GoodGoodGoodPM2.5
Merrimack County7GoodGoodGoodOzone
Carroll CountyNo readingGoodGoodPM2.5
Strafford CountyNo readingGoodGoodPM2.5
Sullivan CountyNo readingGoodGoodPM2.5

Smoke

NOAA’s Hazard Mapping System smoke analysis could not be read just now.

Smoke on the radar over New Hampshire

What this means

The index runs from 0 to 500. Good is 0 to 50, Moderate to 100, Unhealthy for Sensitive Groups to 150, Unhealthy to 200, Very Unhealthy to 300, and Hazardous above that. The figure reported for a place is the highest index among the pollutants measured there, and the pollutant that produced it is named beside it.

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.

Towns

Air quality for any town in New Hampshire: what is measured nearby, the category forecast for today and tomorrow, and NOAA’s model hour by hour. Largest first.

Smaller places have pages too; search for one on the air quality landing page.

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.