Merrimack County, New Hampshire
AQI 38 · Good38
Median AQI
47
90th Percentile
90
Max AQI
122
Days with Data
Ranked #5 of 7 counties in New Hampshire (by median AQI, lower is better)
Monthly Median AQI — 2025
Click a bar to view that month's details
38
Median AQI
47
90th Percentile
90
Max AQI
122
Days with Data
Ranked #5 of 7 counties in New Hampshire (by median AQI, lower is better)
Click a bar to view that month's details