What is the air quality trend in Toronto?

Over the past 15 days, Toronto had an average AQI of 50 based on station measurements. The worst day was 2026-05-20 with AQI 73.

How is Toronto air quality measured?

Air quality in Toronto 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 Toronto, Canada

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

Historical PM2.5 and AQI trend from monitoring stations near Toronto, Canada.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

336h

PM2.5 Station

336h · 10 stations

Temperature GFS model

55pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-05-30	47	21–157	14.0 µg/m³	1.8	12h	13
2026-05-29	50	15–128	14.1 µg/m³	12.1	24h	17
2026-05-28	37	15–70	9.5 µg/m³	1.6	24h	15
2026-05-27	47	20–152	12.6 µg/m³	6.1	24h	13
2026-05-26	38	21–74	9.9 µg/m³	6.0	24h	12
2026-05-25	72	27–172	25.5 µg/m³	11.2	24h	14
2026-05-24	52	22–134	14.4 µg/m³	7.1	24h	17
2026-05-23	52	18–120	14.9 µg/m³	2.7	24h	16
2026-05-22	43	14–114	11.6 µg/m³	5.0	24h	13
2026-05-21	59	24–182	19.7 µg/m³	1.6	24h	16
2026-05-20	73	23–156	23.8 µg/m³	7.2	24h	16
2026-05-19	40	18–91	10.4 µg/m³	8.5	24h	13
2026-05-18	42	21–64	10.7 µg/m³	29.4	24h	12
2026-05-17	64	26–163	20.3 µg/m³	27.7	24h	6
2026-05-16	46	24–92	12.1 µg/m³	12.6	12h	16

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