What is the air quality trend in Westminster?

Over the past 15 days, Westminster had an average AQI of 31 based on station measurements. The worst day was 2026-05-18 with AQI 50.

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 CAMS model

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

286h

PM2.5 Station

286h · 1 station

Temperature GFS model

56pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	Hours	Stations
2026-05-29	22	13–28	5.2 µg/m³	14h	1
2026-05-28	27	11–39	6.4 µg/m³	21h	1
2026-05-27	28	5–50	6.8 µg/m³	22h	1
2026-05-26	29	17–59	7.1 µg/m³	20h	1
2026-05-25	25	2–57	6.1 µg/m³	22h	1
2026-05-24	22	9–50	5.4 µg/m³	20h	1
2026-05-23	28	18–60	6.7 µg/m³	23h	1
2026-05-22	25	13–48	5.9 µg/m³	21h	1
2026-05-21	24	12–39	5.7 µg/m³	20h	2
2026-05-20	32	18–53	7.7 µg/m³	22h	1
2026-05-19	45	31–63	11.4 µg/m³	19h	1
2026-05-18	50	4–69	12.7 µg/m³	21h	2
2026-05-17	42	18–91	10.6 µg/m³	21h	1
2026-05-16	33	3–135	9.0 µg/m³	15h	1
2026-05-15	36	18–49	8.7 µg/m³	5h	1

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