How the West Coast’s only heat officer...

deaths a day by the fifth.

These hospitalizations and deaths disproportionately affect communities of color living in low-income, historically redlined neighborhoods, said Segura, “where the houses don’t have AC or air filtration. When you start approaching heat vulnerability that way, it’s not only a sustainability issue — it’s public works, building development, water and power, tree shade and park access, and certainly a matter of public health.”

Heat is the top public health risk in LA, which experiences heat waves five times more often than it did 10 years ago.

As extreme heat waves in Los Angeles become longer, more frequent and more intense, public outreach becomes ever-more crucial. Across her Heat Relief 4 LA social media campaign, Segura emphasizes that “It’s not your typical summer anymore. Extreme heat can run from June to November. As this means our bodies have less time to recover, we also distribute information on symptoms of heat exhaustion and heatstroke, and resources to cool off before hitting that point.”

Foremost among these resources are cooling centers; in Los Angeles, currently 119 are open. “We’ve established cooling centers and hydration resources throughout the city in facilities like libraries, senior centers and community centers,” said Segura. “We also made an app, Cool Spots LA, where you can find where and when they’re open, alongside other cooling spots like shade structures, hydration stations, and bus shelters.” Currently, only a quarter of all LA Metro bus stops are shaded.

The need for heat interventions like these can vary drastically from neighborhood to neighborhood, partly because of the region’s coastal and inland microclimates. Accordingly, the city’s emergency alert system now uses National Weather Service data to identify heat wave severity in specific parts of LA.

However, these stark regional heat differences also owe to shade inequity. Research shows that with each 10% of canopy cover, trees keep ground-level temperatures about 2 degrees cooler. In a city where over half the surfaces are dark concrete or asphalt — which absorbs up to 90% of solar radiation — 20% of tree canopies are concentrated in four neighborhoods where less than 1% of the population live.

To address this inequity, 65,000 trees have been planted citywide in continuation of a 2019 plan by former Mayor Eric Garcetti to increase canopy coverage 50% by 2028 across LA’s least green neighborhoods. The aim is 90,000 trees by 2028.

Environmental inequity is a testament to why extreme heat is a public health issue, said Segura. “LA’s least green areas are historically