Air Quality Report: Toronto, Ontario – August 3, 2025

Executive Summary

On August 3, 2025, the city of Toronto, Ontario, experienced a significant degradation in air quality, primarily due to transboundary smoke from wildfires in the Canadian Prairie provinces. The Air Quality Health Index (AQHI) reached a “high risk” level of 7, positioning Toronto as one of the world’s most polluted major cities. This event highlights critical challenges related to several United Nations Sustainable Development Goals (SDGs), particularly SDG 3 (Good Health and Well-being), SDG 11 (Sustainable Cities and Communities), and SDG 13 (Climate Action).

Analysis of Air Quality Event

Current Status and Health Implications (SDG 3)

The air quality in Toronto has been officially categorized as poor. This poses a direct threat to public health, undermining progress towards SDG 3: Good Health and Well-being. Key indicators from the event include:

• Air Quality Health Index (AQHI): A rating of 7 indicates a high health risk from air pollution.
• Global Ranking: Toronto was ranked the 3rd most polluted major city globally on the morning of August 3.
• Vulnerable Populations: The conditions present an elevated risk for children, older adults, and individuals with pre-existing respiratory or cardiovascular conditions.

The high concentration of particulate matter from the smoke is a serious public health concern, directly conflicting with the SDG 3 target of substantially reducing deaths and illnesses from hazardous chemicals and air pollution.

Causal Factors: Wildfire Smoke Incursion

The primary cause of the poor air quality is smoke from extensive wildfires burning in Saskatchewan and Manitoba. A high-pressure weather system has transported this smoke southeast into Ontario and trapped it near the surface, leading to elevated concentrations of pollutants in the Greater Toronto Area. This demonstrates the interconnectedness of environmental systems, where events in one region can severely impact distant population centers.

Broader Context and Sustainable Development Goal (SDG) Implications

Challenges to Sustainable Cities and Communities (SDG 11)

This air quality crisis underscores the vulnerability of urban centers to environmental hazards, a key concern of SDG 11: Sustainable Cities and Communities. The goal to make cities inclusive, safe, resilient, and sustainable is challenged when essential systems like air quality are compromised. The event necessitates a re-evaluation of urban resilience strategies and public health infrastructure to better withstand such environmental shocks.

Link to Climate Action and Life on Land (SDG 13 & SDG 15)

The wildfires causing the smoke are symptomatic of broader environmental trends linked to SDG 13: Climate Action and SDG 15: Life on Land. Climate change is associated with an increased frequency and intensity of wildfires, which devastate terrestrial ecosystems, forests, and biodiversity (SDG 15). This event serves as a clear example of how climate-related disasters directly impact human health and the sustainability of our communities, reinforcing the urgent need for comprehensive climate action to mitigate these cascading effects.

Official Advisories and Recommended Protective Measures

Government Alerts and Affected Regions

In response to the hazardous conditions, Environment Canada has issued special air quality statements across multiple provinces. These alerts are a critical component of public safety and align with the need for effective risk reduction strategies. The primary regions under advisory include:

1. Ontario
2. Quebec
3. Saskatchewan
4. Manitoba
5. Alberta
6. Northwest Territories (parts)

Public Health Recommendations

To protect public health and support SDG 3, residents in affected areas, particularly Toronto, are advised to take precautions. Health officials recommend limiting strenuous outdoor activities. Exposure to high levels of particulate matter can cause a range of symptoms, including:

• Irritation of the eyes, nose, and throat
• Headaches
• Mild or severe coughing
• Chest discomfort or wheezing

Adherence to local health advisories is strongly encouraged to mitigate the adverse health impacts of this air quality event.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

• SDG 3: Good Health and Well-being: The article directly addresses health risks associated with poor air quality. It mentions an “Air Quality Health Index” at a “high risk” level, lists symptoms from exposure (eye/nose/throat irritation, headaches, coughing), and advises vulnerable populations like children, older adults, and those with pre-existing conditions to take precautions.
• SDG 11: Sustainable Cities and Communities: The focus of the article is on the city of Toronto, which is described as ranking “3rd among the most polluted cities in the world” due to the smoke. This highlights the challenge of maintaining a safe and healthy urban environment.
• SDG 13: Climate Action: The source of the air pollution is identified as “drifting wildfire smoke.” Wildfires are a natural hazard whose frequency and intensity are often linked to climate change. The article discusses the impact of this climate-related hazard on a major population center.
• SDG 15: Life on Land: The wildfires burning in the Prairie provinces (“Saskatchewan and Manitoba”) are a direct impact on terrestrial ecosystems. While the article focuses on the effect of the smoke, the cause is rooted in the health and management of forests and land.

2. What specific targets under those SDGs can be identified based on the article’s content?

1. Target 3.9: By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination.
   • The article’s entire premise is about the health impact of air pollution from wildfire smoke. It details the “high risk” level and lists specific health “symptoms from exposure,” which are the illnesses this target aims to reduce.
2. Target 3.d: Strengthen the capacity of all countries… for early warning, risk reduction and management of national and global health risks.
   • The article explicitly states that “Environment Canada has issued special air quality statements and warnings” and that the public is “advised to limit outdoor activities.” This is a direct example of an early warning and risk reduction system in action to manage a national health risk.
3. Target 11.6: By 2030, reduce the adverse per capita environmental impact of cities, including by paying special attention to air quality…
   • The article focuses on the “poor air quality” in Toronto, noting it “ranked 3rd among the most polluted cities in the world.” This directly relates to the environmental impact of a city, specifically concerning air quality.
4. Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries.
   • Wildfires are a climate-related natural hazard. The issuance of “special air quality statements and warnings” and public health advisories are measures that demonstrate a country’s adaptive capacity to the impacts of such hazards.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

1. Indicator 11.6.2: Annual mean levels of fine particulate matter (e.g. PM2.5 and PM10) in cities (population weighted).
   • The article explicitly mentions that the wildfire smoke has generated “high concentrations of particulate matter.” The “Air Quality Health Index for the region is rated at 7” and Toronto’s ranking as a “most polluted” city are direct measurements related to this indicator.
2. Indicator for Target 3.9: Mortality rate attributed to air pollution.
   • While the article does not mention deaths, it lists specific “symptoms from exposure” such as “severe coughing” and “chest discomfort.” The prevalence and severity of these illnesses serve as a proxy indicator for the health burden from air pollution.
3. Indicator for Targets 3.d and 13.1: Adoption and implementation of national disaster risk reduction strategies.
   • The article provides evidence of such a strategy in action. The fact that “Environment Canada has issued special air quality statements and warnings” and that there are advisories for the public to “limit outdoor activities” demonstrates an implemented early warning and risk reduction system.

4. Summary Table of SDGs, Targets, and Indicators

Source: iqair.com