What is the air quality trend in Merrimack?

Over the past 7 days, Merrimack had an average AQI of 56 based on station measurements. The worst day was 2026-07-17 with AQI 99.

How is Merrimack air quality measured?

Air quality in Merrimack is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for Merrimack, United States

Name: Merrimack Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near Merrimack, United States.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

166h

PM2.5 Station

166h · 2 stations

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	Hours	Stations
2026-07-21	38	17–63	9.4 µg/m³	23h	3
2026-07-20	51	14–95	13.7 µg/m³	24h	4
2026-07-19	50	18–139	13.6 µg/m³	24h	4
2026-07-18	57	26–131	16.7 µg/m³	23h	4
2026-07-17	99	31–179	42.9 µg/m³	24h	4
2026-07-16	54	29–167	16.2 µg/m³	24h	4
2026-07-15	47	30–63	12.0 µg/m³	24h	4

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