What is the air quality trend in Crystal Lake?

Over the past 8 days, Crystal Lake had an average AQI of 97 based on station measurements. The worst day was 2026-07-17 with AQI 227.

How is Crystal Lake air quality measured?

Air quality in Crystal Lake 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 Crystal Lake, United States

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

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

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

168h

PM2.5 Station

168h · 1 station

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	Hours	Stations
2026-07-22	28	24–32	6.7 µg/m³	2h	2
2026-07-21	61	31–97	17.8 µg/m³	24h	79
2026-07-20	98	42–107	34.3 µg/m³	24h	77
2026-07-19	110	62–161	40.3 µg/m³	24h	80
2026-07-18	50	9–90	13.1 µg/m³	24h	80
2026-07-17	227	73–348	173.2 µg/m³	24h	84
2026-07-16	158	49–326	103.7 µg/m³	24h	78
2026-07-15	51	50–56	12.4 µg/m³	22h	80

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