What is the air quality trend in Diamond Bar?

Over the past 8 days, Diamond Bar had an average AQI of 40 based on station measurements. The worst day was 2026-07-19 with AQI 46.

How is Diamond Bar air quality measured?

Air quality in Diamond Bar 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 Diamond Bar, United States

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

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

Current AQI
Good CAMS model

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

168h

PM2.5 Station

168h · 2 stations

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-07-21	35	9–42	8.3 µg/m³	4.1	23h	97
2026-07-20	45	12–53	10.9 µg/m³	7.1	24h	97
2026-07-19	46	22–53	11.1 µg/m³	7.9	24h	101
2026-07-18	39	24–44	9.4 µg/m³	5.4	24h	102
2026-07-17	44	35–53	10.6 µg/m³	9.5	24h	106
2026-07-16	40	36–45	9.6 µg/m³	5.6	24h	98
2026-07-15	38	20–45	9.1 µg/m³	5.3	24h	103
2026-07-14	33	33–33	8.0 µg/m³	8.0	1h	1

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