Vancouver Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Vancouver (Portland-Vancouver-Hillsboro, OR-WA area) was September 13, 2020, when the daily AQI reached 874 (Hazardous), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,557 monitored days in 2019–2025, 10 of the 10 worst days were Unhealthy (AQI 151+) or worse; 10 of the 10 were driven by fine particulate matter (PM2.5), and 8 of them fell in 2020. The cleanest day was August 15, 2025 at AQI 17 (Good); the 10 best days span 5 different years.
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When were Vancouver's worst and best air quality days?
Worst: September 13, 2020, AQI 874 (Hazardous, PM2.5). Best: August 15, 2025, AQI 17 (Good). Based on 2,557 EPA-monitored days in the Portland-Vancouver-Hillsboro, OR-WA area, 2019–2025.
- ✓10 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 169 (Unhealthy).
- ✓Fine particulate matter (PM2.5) drove 10 of the 10 worst days.
- ✓2020 accounts for 8 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Vancouver?▾
September 13, 2020: the Portland-Vancouver-Hillsboro, OR-WA area's daily AQI hit 874 (Hazardous), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Vancouver?▾
August 15, 2025, with a daily AQI of 17 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Vancouver's worst air quality day in 2025?▾
August 23, 2025, AQI 119 (Unhealthy for Sensitive Groups), set by ground-level ozone, in peak ozone season.
Which pollutant causes Vancouver's worst air days?▾
Fine particulate matter (PM2.5) set the AQI on 10 of the 10 worst days. The tables above list the defining pollutant for every day.
Vancouver's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Portland-Vancouver-Hillsboro, OR-WA area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2020 page) | 874 | Hazardous | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2020 page) | 842 | Hazardous | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2020 page) | 595 | Hazardous | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 4 | (2020 page) | 526 | Hazardous | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 5 | (2020 page) | 413 | Hazardous | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 6 | (2020 page) | 325 | Hazardous | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 7 | (2020 page) | 278 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 8 | (2020 page) | 240 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 9 | (2022 page) | 175 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 10 | (2022 page) | 169 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Worst day of each year in Vancouver
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 128 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) | |
| 2020 | 874 | Hazardous | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2021 | 161 | Unhealthy | O3 — ground-level ozone, in peak ozone season | |
| 2022 | 175 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2023 | 153 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 127 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5) | |
| 2025 | 119 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
Vancouver's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Portland-Vancouver-Hillsboro, OR-WA area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2025 page) | 17 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 2 | (2021 page) | 17 | Good | O3 — ground-level ozone |
| 3 | (2024 page) | 19 | Good | O3 — ground-level ozone |
| 4 | (2025 page) | 21 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2025 page) | 21 | Good | O3 — ground-level ozone, in peak ozone season |
| 6 | (2025 page) | 21 | Good | O3 — ground-level ozone, in peak ozone season |
| 7 | (2025 page) | 21 | Good | O3 — ground-level ozone, in peak ozone season |
| 8 | (2021 page) | 21 | Good | O3 — ground-level ozone, in peak ozone season |
| 9 | (2020 page) | 21 | Good | O3 — ground-level ozone, in peak ozone season |
| 10 | (2019 page) | 21 | Good | O3 — ground-level ozone |
Right now in Vancouver
The latest EPA AirNow observation puts Vancouver's AQI at 28 (PM2.5). The days above are historical records, not today's reading.
View current Vancouver air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Portland-Vancouver-Hillsboro, OR-WA), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.