What is the air quality trend in Ontario?

Over the past 15 days, Ontario had an average AQI of 37 based on station measurements. The worst day was 2026-06-05 with AQI 61.

How is Ontario air quality measured?

Air quality in Ontario 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 Ontario, United States

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

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

Current AQI
Moderate Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

336h

PM2.5 Station

336h · 1 station

Temperature GFS model

56pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-06-09	37	17–50	8.8 µg/m³	5.3	10h	24
2026-06-08	38	30–48	9.1 µg/m³	6.2	24h	29
2026-06-07	38	35–42	9.1 µg/m³	6.0	24h	30
2026-06-06	46	35–55	11.2 µg/m³	10.7	24h	29
2026-06-05	61	49–92	17.0 µg/m³	18.8	24h	31
2026-06-04	51	38–64	12.9 µg/m³	13.3	24h	31
2026-06-03	51	35–63	13.0 µg/m³	10.3	24h	30
2026-06-02	50	39–58	12.5 µg/m³	10.5	24h	31
2026-06-01	42	29–52	10.0 µg/m³	8.0	24h	27
2026-05-31	36	25–47	8.7 µg/m³	6.1	24h	30
2026-05-30	23	17–32	5.5 µg/m³	2.1	24h	30
2026-05-29	20	17–29	4.8 µg/m³	0.7	24h	30
2026-05-28	21	4–60	5.1 µg/m³	0.9	24h	28
2026-05-27	22	19–28	5.2 µg/m³	1.5	24h	30
2026-05-26	25	22–28	6.1 µg/m³	3.1	14h	30

Back to Ontario Air Quality