What is the air quality trend in Johnston?

Over the past 7 days, Johnston had an average AQI of 54 based on station measurements. The worst day was 2026-07-20 with AQI 66.

How is Johnston air quality measured?

Air quality in Johnston 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 Johnston, United States

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

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

Current AQI
Moderate Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

114h

PM2.5 Station

114h · 1 station

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	Hours	Stations
2026-07-21	53	18–89	14.9 µg/m³	14h	2
2026-07-20	66	13–179	23.8 µg/m³	14h	1
2026-07-19	51	25–107	13.7 µg/m³	17h	1
2026-07-18	64	17–188	24.3 µg/m³	14h	1
2026-07-17	54	42–82	14.1 µg/m³	15h	1
2026-07-16	50	23–154	13.7 µg/m³	19h	1
2026-07-15	46	19–89	12.4 µg/m³	21h	1

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