Poor Air Quality Expected on Sunday as Wildfire Smoke Returns to Ontario

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Numerous uncontrolled wildfires have been raging in Northern Ontario and Quebec for several weeks. In early June, we experienced the effects of the smoke as it drifted southward, leading to poor air quality in Southern Ontario. At times, the air quality was among the worst worldwide.

In the past few weeks, we've occasionally encountered blasts of wildfire smoke, mainly in Eastern Ontario and the Golden Horseshoe region. Fortunately, the weather patterns have mostly kept the heaviest smoke away from our area. However, this is about to change. On Sunday, we anticipate the most widespread and dense near-surface smoke since the beginning of the week. The thickest smoke is expected to arrive late Saturday evening or just after midnight.

Central Ontario (Muskoka, Parry Sound, Algonquin Park, etc.) and areas along the Quebec border, including Ottawa and Renfrew, are likely to experience the worst conditions. The air quality in these regions will be severely compromised throughout Sunday, potentially reaching unsafe levels even for those who are not typically sensitive to air pollution. It is advised to minimize outdoor exposure as much as possible.

As we move southwest, the smoke intensity is expected to decrease. Moderate levels of smoke are anticipated in Kingston, Peterborough, the Greater Toronto Area (GTA), and Barrie. While the air quality won't be as severe, the smell of smoke may still be noticeable, and individuals with pre-existing conditions may experience symptoms. Southwestern Ontario is not expected to be significantly impacted, with minimal or no near-surface smoke..

The most hazardous air quality is anticipated in Northern Ontario, particularly around the Sudbury region along with Cochrane and parts of Northwestern Ontario where active fires persist.

Forecasting the smoke conditions in Northern Ontario is challenging due to the complexity of distinguishing between local fire-generated smoke and smoke drifting over from Quebec. The forecast for the northwest region depends on the behaviour of fires near Fort Hope over the next 12-24 hours, making it less certain.

Moderate to heavy smoke is expected across all of Northern Ontario, although Thunder Bay should experience less severe conditions.

Southern Ontario is expected to see a reduction in smoke by late Sunday, but smoke may linger in Northern Ontario into Monday. A strong westerly flow will push the smoke from Quebec directly into the northern region

Upcoming Wildfire Smoke Poses Serious Air Quality Risks for Southern Ontario

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While we've seen some marginal improvement in air quality this evening as surface-level smoke dissipates, Southern Ontario isn't out of the woods just yet. An extensive plume of smoke is shifting our way and is expected to affect the region overnight and into early Wednesday.

Current data suggest that this incoming wave of smoke could degrade air quality even further than what we witnessed today. Petawawa is already feeling the impact with an Air Quality Index (AQI) of 430, a level significantly above the "very hazardous" category. In fact, Petawawa currently has some of the worst air quality globally, excluding specific regions in South America and India.

This severe air quality is what we anticipate waking up to on Wednesday. Models suggest the heaviest smoke concentration will target Eastern and Central Ontario, although the Greater Toronto Area (GTA) may also face thick smoke. While less smoke is expected in the southwest, air quality remains a concern across the region.

While we predict some respite later on Wednesday, brace for the arrival of an even more intense smoke plume on Thursday, potentially affecting the GTA and Southwestern Ontario. The severity of this situation is unprecedented, making it difficult to predict the exact level of impact.

Many locations across Southern Ontario may report the worst air quality in recorded history, and the pollutants in the air could pose a critical threat to those exposed for extended periods. We recommend staying indoors as much as possible over the next couple of days, especially during the early part of Wednesday and Thursday. This is a serious health concern, regardless of pre-existing conditions.

Looking ahead, a shift in wind direction over the weekend might provide a temporary respite, but the potential for more smoke next week remains, depending on fire activities.

At Instant Weather, we are committed to providing regular updates on active wildfires, smoke, and air quality across Southern Ontario. Please continue checking our updates for crucial information in the coming days.