B COOL: A Heat Temperature Sensor Pilot Project Recap

On the coldest day of the season thus far, a dedicated gathering shivered into the Boston Foundation’s Edgerley Center for Civic Leadership to talk about extreme heat. More specifically, the group aimed to talk about results of a heat sensor pilot program completed in 2024 that aimed to address the data gaps in measuring temperature data across Boston’s hotspot neighborhoods, which can be 10-15 degrees warmer than surrounding neighborhoods.

TBF, in partnership with A Better City, Boston University School of Public Health, and the City of Boston, presented findings from the 2024 B-COOL pilot project. Building upon existing research, the goal was to better understand whether neighborhood-specific temperature sensor data might be incorporated into more targeted heat emergency declarations and protocols for Boston, as well as inform the city, local institutions, and community-based partners on how to distribute available resources to heat-vulnerable residents and workers.

The session opened with an overview of heat and public health. Sometimes called a “silent killer,” extreme heat is becoming more common. It doesn’t affect everyone equally, of course—the very old and very young are especially vulnerable, as well as people with underlying health conditions and those who live in crowded spaces, with no air-conditioning or cross-ventilation, and in places with few trees or vegetation. Members of the research team showed one of the sensors—with its protective casing, about the size of a volleyball. Sensors were placed in Allston Brighton, Chinatown, Dorchester, East Boston, Jamaica Plain, Mattapan, and Roxbury, with two sensors in each neighborhood, one nearer to trees and another in a more asphalt-rich environment.

In the summer of 2024, there were several declared heat advisories (90˚ Fahrenheit for more than two days in a row) or emergencies (95˚ F for more than two days) for Boston, based on National Weather Service forecasts for Logan Airport. The question was: Did the alerts issued reflect people’s experience on the ground?

With an advisory, an alert is sent out via various media, and with an emergency, the alert is paired with the opening of cooling centers. The pilot project results suggest that neighborhood readings were not always well aligned with the airport’s forecasted temperatures. In the first alert of the summer, the predicted temperature threshold was not reached; however, later in August, when a heat advisory was issued, almost all the neighborhood heat sensors identified temperatures that met the heat emergency level. In short, if your benchmark for regional heat is at the breezy coastal airport, it may not reflect what the majority of city dwellers are feeling—or serve as an accurate prompt for the City or other agencies to take action.

After the presentation, the multidisciplinary audience went into workshop mode, with breakouts focused on vulnerable populations, urban infrastructure and design, and emergency management policy and governance.

As TBF Senior Program Officer Julia Howard summarized, "We cannot make progress on climate resilience without addressing the issues this pilot program underscored—that many areas feeling the greatest heat are those that lack the green space and infrastructure to mitigate it. The B-COOL data reaffirm that any commitment we make to housing equity needs to include attention to elements of climate in our neighborhoods."