How Toronto is using data to build climate resilience

This past July, Torontonians woke up to a hazy orange sky – a significant air quality event caused by wildfire smoke had blanketed the city, lasting days and prompting Toronto’s local public health unit to activate its Wildfire Response Strategy.

It’s the latest sign that Toronto’s summers are changing. In 2025, Torontonians experienced one of the hottest summers of the past decade, with nearly 30 days recording temperatures exceeding 30°C . Extreme heat and wildfire smoke can worsen heart and lung conditions, contribute to heat-related illness and increase demand on health services.

This isn't unique to Toronto. Extreme heat is now a leading cause of deaths globally, killing nearly 500,000 people every year. The risks are greatest for older adults, infants and young children, people with chronic diseases, people experiencing homelessness and those without access to adequate cooling or cleaner indoor air.

Impacts are also unequal: neighborhoods with fewer trees, green spaces and access to cooling can experience higher temperatures, making clear, timely information even more critical.

Like other cities around the world, Toronto is confronting the growing health impacts of climate change and taking steps to prepare residents before the next heat wave or smoke event hits. Working with the Partnership for Healthy Cities, local public health officials wanted to find out: Do people change their behaviour when a heat warning or air quality alert hits? And if not, why?

In two surveys (general population and 65+ years of age), Toronto Public Health reached 1,934 Torontonians in 2025 and asked how they respond to extreme heat and wildfire smoke. The results revealed a critical gap: Even when people know the risks, far fewer are acting on that awareness. The city is now using data to try to change this, ensuring that the response is targeted and grounded in evidence.

The surveys were able to demonstrate how residents respond to heat warnings and wildfire smoke events, including the barriers people face.

On heat:

• The surveys revealed a clear gap between awareness and action. While 72% of residents listen for heat warnings and find them useful, only 41% of residents reported ever using cooling options, such as public air-conditioned spaces, extended pool hours or splash pads.

• Among respondents aged 65 and older, up to 38%indicated they would not leave home to access a cooler space during extreme heat.

• Nearly 20% of heat-vulnerable residents (people with disabilities, chronic diseases, lower incomes or who live alone) did not have air conditioning.

• 30% of residents may need help coping with heat, especially those without air conditioning.

On wildfire smoke:

• 58% of residents recalled seeing or hearing air quality messages about wildfire smoke.

• One-third reported taking no protective action during smoke events.

• Only 15% reported having a portable air purifier at home, with access lower among households earning less than CAD $50,000.

Barriers exist. Cost can prevent people from using air conditioning or an air purifier, while social isolation can also make it harder for people to ask for help that could help them stay healthy.

It would be easy to read these numbers and conclude that Toronto needs louder alerts, or more of them. That's not quite the lesson.

Toronto Public Health plays an important role in helping residents understand the health risks of heat and wildfire smoke. What the data showed is that the challenge isn’t access to information; it’s the ability to access cooling centers, the use of air conditioning and other protective measures.

Local public health officials used the findings to help close the communications gap by making heat and wildfire smoke information clearer and easier to act on. Plain-language messaging on digital channels focused on timely, practical actions, such as finding cool or cleaner-air spaces, checking the Air Quality Health Index, and staying hydrated.

The city also made its advice about checking in on people at greater risk during extreme heat more specific and actionable. Rather than simply telling residents to “check in,” messaging encouraged people to ask about the temperature inside someone’s home and take action if it had been sustained above 26°C for example, helping them get to a cooler space. Updated warnings and public-facing materials in multiple languages now more clearly explain the level of risk, who may be most affected and what actions to take, helping residents move from awareness to action.

The findings from the surveys didn’t stay in a report. They are shaping broader City of Toronto planning, programs and are helping inform policies for years to come.

Toronto's 2026 Heat Relief Strategy strengthened communications about cooling spaces, community supports and services offered by various City departments. The City's Air Conditioner Assistance Program  targets the exact cost barrier that the survey identified. Toronto is also strengthening its approach to wildfire smoke, including promoting Cleaner Air Spaces and helping residents understand how to use the Air Quality Health Index and Environment & Climate Change Canada's new colour-coded air quality alert system.

The surveys reinforce an important lesson for cities everywhere: Good public health communication isn't only about what people know. It's about helping people act.

That means understanding the barriers residents face, designing communications around their needs and working with community organizations, health care providers and other trusted partners to reach people who may be at greater risk.

Effective communication is an essential part of responding to extreme heat and wildfire smoke, connecting timely warnings with practical guidance, using plain language, trusted support and the resources residents need to protect their health. It’s not about being louder; it’s about being closer when we communicate with our diverse communities.