The Ohio Environmental Protection Agency has discontinued the statewide Air Quality Advisory it issued due to smoke from wildfires in Canada drifting into the region.
The wildfire smoke has caused widespread haze throughout the country, prompting delays at airports in New York City; Philadelphia; Newark, New Jersey, and Washington, D.C. Air quality in Cincinnati and other cities this week was also reportedly worse than in Beijing and Shanghai, cities notoriously plagued by air pollution.
New York's air quality index even reached 380, a hazardous level.
Cincinnati weather: Hazy, dry conditions continue, storms to approach this weekend
'Everybody will lose their village': Kings Island ride closure hurts local surfing community
The Southwest Ohio Air Quality Agency advises residents to take several precautions to mitigate exposure to harmful air pollutants, such as taking the bus, carpooling or walking instead of driving.
But where did the wildfires start, and have they been contained?
Here's what we know.
Where are the wildfires in Canada?
The wildfires started in the western provinces of British Columbia and Alberta and have spread to the eastern regions of Nova Scotia, Quebec and Ontario, Reuters reports.
As of Thursday, there were nearly 2,300 fires in nine of the country’s 13 provinces and territories that have destroyed approximately 9.4 million acres of forest, according to The Washington Post. The fires have forced more than 100,000 people from their homes and have caused widespread haze and air pollution throughout North America.
The province of Quebec has had 154 active wildfires, the most in the country.
When did the wildfires start?
The wildfires started in late April, displacing more than 30,000 people at its peak, per Reuters.
What started the wildfires in Canada?
The forest fires in Quebec were caused by lightning, according to Reuters. Half of the wildfires in Canada are caused by lightning, and those fires are responsible for over 85% of wildfire destruction in the country, CBS News reported.
The cause of wildfires in Alberta is still unknown, but fires in other parts of the country are believed to be caused by human activity, like discarding cigarettes from passing trains.
All fires, whether caused by lightning or people, thrive under conditions that include dry vegetation and hot and windy weather.
Are the Canadian wildfires under control?
Vox reports that roughly 140 fires were burning across Canada's eastern seaboard as of Thursday morning, and many had not been contained.
Canada has committed all of its national resources, including deploying its Armed Forces to highly affected areas like Alberta and Quebec, to mitigate the spread of the fires, according to The Washington Post. Approximately 1,000 firefighters from the United States, South Africa and other countries have also sent aid.
Despite these efforts, Vox writes the fires could persist for months if Canada continues experiencing dry and warmer-than-average conditions this summer.
Effects of the 2023 Canadian wildfires
The wildfires displaced over 30,000 Canadian residents during its peak, per CBS News. Oil and gas production also halted in the country.
Wildfire smoke has also negatively impacted air quality throughout the United States, including Greater Cincinnati. Although air pollution inhalation due to wildfire smoke is a concern for everyone, it could be especially hazardous for people with heart disease, asthma or chronic obstructive pulmonary disease (COPD).
'Difficult to avoid:' Air pollutants present challenges to vulnerable
Northeast cities like New York, Philadelphia and Washington, D.C., have been encompassed by orange fog and have experienced some of the worst effects in the U.S. The New York Department of Environmental Conservation has advised residents to remain indoors and wear face masks during necessary trips outside.
Many outdoor activities and baseball games have been canceled in New York and Philadelphia this week as a result. The FAA also delayed flights to airports in New York City, Philadelphia, Newark and Washington, D.C., due to low visibility from wildfire smoke.
Canadian wildfire smoke map
This article originally appeared on Cincinnati Enquirer: What started Canada's wildfires? When did they start? What to know