Wildfire smoke · North-eastern United States
New York under Canada's smoke
On the afternoon of 7 June 2023 the Manhattan skyline vanished into an orange haze. Smoke from wildfires burning across Quebec, 800 km to the north, had been funnelled south by a slow low over the Atlantic coast. New York's air quality index passed 480, the city briefly had the worst air in the world, and people were told to stay indoors.
6–8 June 2023 · New York and the US north-east · CAMS, ERA5
104µg m⁻³
Surface PM2.5, 7 June
CAMS, nearest grid point to New York. The June normal there is 22.
484
Air quality index, 5 pm
New York on 7 June, the worst of any large city in the world that afternoon.N1
+43 %
Asthma visits to emergency rooms
261 a day on the worst day against about 182 before and after.S1
What happened
Early June 2023 saw an extraordinary outbreak of wildfires in Quebec, many lit by lightning in a dry, warm spring. On 6 June their smoke reached New York; on 7 June it thickened into an orange fog. The air quality index reached 484 in the late afternoon, flights were held at the city's airports and schools cancelled outdoor activities.N1N2
Researchers counted 261 emergency visits for asthma in the city on 7 June, against about 182 a day in the weeks before and after.S1
The smoke's path
The smoke sat over Quebec and Ontario on 5 June. Two days later the same air lay over New York, Philadelphia and Washington, carried south along the coast.
Why it came south
Smoke from Canadian fires usually drifts east with the westerlies, out over the Atlantic. In early June 2023 a slow low sat over the Gulf of Maine and Nova Scotia. Air circles a low anticlockwise, so on its western side the wind blew from the north: from the fires in Quebec straight down the Hudson valley to New York.
Under the low the smoke was also kept near the ground, which is why the air people breathed was so bad rather than only the sky being hazy.
The air at street level
×7
The CAMS daily PM2.5 near New York on 7 June against the WHO 24-hour guideline of 15 µg m⁻³.G1 Monitors across the city averaged 101 µg m⁻³ over 6–8 June, close to the reanalysis.S1
| Day | PM2.5 µg m⁻³ | Smoke AOD |
|---|---|---|
| Jun 5 | 10 | 0.09 |
| Jun 6 | 28 | 0.81 |
| Jun 7 | 104 | 1.48 |
| Jun 8 | 95 | 1.05 |
| Jun 9 | 40 | 0.61 |
| June normal | 22 | 0.15 |
Explore in the Lab
Open the event in the Climate mode
Each button opens the Lab on that view, with the date, map layer and data set already chosen.
References
News
- N1CNBC. Canadian wildfire smoke pushes NYC residents indoors, city briefly had world's worst air quality. 7 June 2023.The air quality index of 484 and the city's response.
- N2Royal Meteorological Society, MetMatters. Worst air quality in the world: wildfire smog smothers New York. June 2023.The worst air in the world, and the weather behind it.
Studies and guidelines
- S1Chen, K., Ma, Y., Bell, M. L., Yang, W. (2023). Canadian wildfire smoke and asthma syndrome emergency department visits in New York City. JAMA, 330(14), 1385.Asthma emergency visits and the measured PM2.5 in New York.
- G1World Health Organization (2021). WHO global air quality guidelines. Particulate matter, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide.The 24-hour PM2.5 guideline of 15 µg m⁻³.