What is the air quality trend in Westminster?

Over the past 8 days, Westminster had an average AQI of 41 based on station measurements. The worst day was 2026-08-30 with AQI 54.

How is Westminster air quality measured?

Air quality in Westminster 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 Westminster, United States

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

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

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

165h

PM2.5 Station

165h · 173 stations

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-09-05	34	29–44	8.1 µg/m³	5.4	17h	171
2026-09-04	31	25–36	7.4 µg/m³	5.0	24h	172
2026-09-03	37	28–42	8.9 µg/m³	6.5	24h	172
2026-09-02	34	31–38	8.1 µg/m³	6.0	24h	172
2026-09-01	39	32–45	9.3 µg/m³	6.7	24h	164
2026-08-31	50	45–54	12.0 µg/m³	9.6	24h	170
2026-08-30	54	53–56	13.6 µg/m³	10.8	24h	171
2026-08-29	53	52–53	12.9 µg/m³	10.3	4h	172

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