Los Angeles County unveils CHAP data viewer to help cities and applicants target heat-resilience investments

Los Angeles County officials demonstrated a new County Heat Action Plan (CHAP) data viewer during a webinar overviewing tools, datasets and example use cases to support local heat-resilience planning and state grant applications. The Chief Sustainability Office (CSO) presented layers that link heat exposure, social vulnerability and community assets to help jurisdictions prioritize interventions.

The CHAP, adopted by the Los Angeles County Board of Supervisors in February, sets three goals: cool outdoor spaces, make indoor spaces more heat-resilient, and provide time-sensitive heat-safety communications and services. Andres Gonzalez, sustainability policy advisor at the Chief Sustainability Office, said the viewer is intended to help county departments, cities and community partners apply the plan’s guidance and ground grant proposals in local data.

Ally Fzini of the CSO led the demonstration of the data viewer’s core layers and resources. “We have uploaded two layers that prospective applicants are required to reference when completing applications for the state’s extreme heat grant program,” she said, pointing to the state-designated disadvantaged communities (DAC) and severely disadvantaged communities (SDAC) census-tract layers. Fzini explained that applicants can identify up to five tracts for funding-priority points (DAC = 10 points; SDAC = 15 points).

Presenters emphasized that the viewer combines outcome measures with exposure and capacity indicators. “This layer was created by the UCLA Center for Healthy Climate Solutions. It is zip-code level data, and it’s our only data on actual outcomes,” a presenter noted when describing the heat-health burden layer that shows higher emergency-room visit rates during hot days. The viewer also includes a census-tract social-sensitivity index, a CalEnviroScreen–style pollution layer, and temperature and urban-surface layers that illustrate how air temperature and built materials (asphalt, concrete) contribute to local heat.

The tool provides several planning-relevant metrics: a 95th‑percentile (“average hot day”) air-temperature layer with baseline and mid-/late-century projections (examples shown: baseline ~94.2°F; mid‑century up to ~99°F; late‑century ~102°F), rooftop albedo derived from LARAC aerial imagery, impermeable-surface percentages, tree-canopy and percent-total-shade layers, and community-asset maps (hospitals, schools, parks and cooling centers).

Jean-Claude from the UCLA Luskin Center for Innovation explained the pedestrian-focused datasets: “We developed the pedestrian density layer which is based on smartphone location,” he said. The team interpolated location points to create walkway segments and computed average pedestrian presence and shade conditions for sidewalks, bus stops and parks so planners can identify high-use but low-shade corridors.

County staff also demonstrated datasets that can inform indoor-focused interventions: a Department of Energy–derived energy-burden layer that highlights census tracts where households spend a high share of income on utilities and an experimental U.S. Census–modeled air-conditioning availability layer that estimates access to AC but not usage. Presenters warned that access does not guarantee use, noting that high energy burden can limit residents’ ability to run cooling devices.

To illustrate practical applications, presenters ran two scenarios. In Pasadena they used the viewer to compare heat-health burden, social sensitivity, tree canopy, rooftop albedo and energy burden to decide whether indoor or outdoor interventions were a better fit for a vulnerable tract. In a second scenario focused on Boyle Heights, they filtered community statistical areas to show heavy coverage of severe DAC designations, elevated social-sensitivity indicators (for example, a higher share of older adults living alone and limited-English households), and ER-visit statistics that strengthen an application for the state extreme-heat competitive program.

Presenters closed by noting planned updates (for example, expanding the shade-at-bus-stops layer to include providers beyond Metro) and inviting partners to consult the CHAP web page for the data viewer, the user guide, the public engagement toolkit and the outdoor-interventions handbook. The CSO encouraged jurisdictions preparing grant applications to pair the viewer’s outputs with on-the-ground community engagement to refine priorities and project design.

Next steps: the County will update layers over time and accept feedback for future enhancements; staff recommended that prospective applicants use the viewer alongside field verification and partner outreach before finalizing grant applications.