What is the air quality trend in Saint-Léonard?

Over the past 15 days, Saint-Léonard had an average AQI of 20 based on station measurements. The worst day was 2026-10-21 with AQI 116.

How is Saint-Léonard air quality measured?

Air quality in Saint-Léonard 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 Saint-Léonard, Canada

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

Historical PM2.5 and AQI trend from monitoring stations near Saint-Léonard, Canada.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

300h

PM2.5 Station

300h · 2 stations

Temperature GFS model

56pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	PM10 avg	Hours	Stations
2026-10-21	116	116–116	41.6 µg/m³	8.0	1h	2
2026-10-20	15	1–51	3.6 µg/m³	1.8	23h	2
2026-10-19	12	3–25	2.9 µg/m³	0.9	24h	2
2026-10-18	7	1–26	1.8 µg/m³	0.7	23h	2
2026-10-17	4	3–6	1.0 µg/m³	4.0	5h	1
2026-10-16	21	3–47	5.1 µg/m³	2.5	22h	2
2026-10-15	10	1–46	2.4 µg/m³	2.3	20h	2
2026-10-14	12	2–49	2.9 µg/m³	1.6	24h	2
2026-10-13	10	1–35	2.4 µg/m³	2.1	23h	1
2026-10-12	23	4–55	5.7 µg/m³	2.3	24h	2
2026-10-11	18	7–50	4.3 µg/m³	1.7	24h	2
2026-10-10	7	2–25	1.6 µg/m³	1.8	20h	2
2026-10-09	9	1–42	2.1 µg/m³	3.0	21h	1
2026-10-08	27	4–64	6.5 µg/m³	2.2	24h	2
2026-10-07	9	2–40	2.1 µg/m³	0.9	22h	2

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