How to Use - Cooling Where It Counts

How to Use This Tool

This interactive map helps you explore where targeted albedo cooling (applying reflective coatings to rooftops, parking lots, and roads) would be most effective in reducing urban heat and preventing heat-related deaths across Los Angeles County.

The map is divided into squares, each representing a 250-square-meter area — about the size of a doubles tennis court. Each square is colored to show how effective albedo cooling would be in that specific location.

1. Choose Your Visualization

Select between two viewing modes:

Cost/Benefit Analysis: Identify where in the county applying reflective coatings to pavements would provide the best return on investment based on historical relationships between temperature, demographics, and heat-related mortality risk (darker blue = higher benefit-to-cost ratio)
Cooling Potential: Show temperature reduction achievable by applying reflective coatings to all impervious surfaces (yellow = highest cooling potential))

2. Adjust Parameters

The control panel next to the map lets you explore how assumptions about albedo cooling, its costs, and the benefits of reduced mortality risk affect the results of the analysis.

The cost-benefit parameters you can adjust are:

Cost per square meter of reflective coating: The main parameter that affects the county-wide cost of albedo cooling. Increasing this value implies that fewer parts of the city would be cost-effective to treat.
Discount rate: How much we value future benefits in present-day terms. Increasing the discount rate means we are de-prioritizing the future relative to the present, so the long-term benefit of albedo cooling would lessen.
Value of a statistical life: How much we value each death prevented by albedo cooling. The more we value each prevented death, the more it makes sense to invest in albedo cooling. We compute the economic value of reduced mortality risk using the VSL, adjusted for life years saved using conditional life expectancies.

You can also optionally add a budget constraint. In this case, the cells which make the most sense to treat with reflective coatings within that budget are colored purple on the map. Cells are prioritized by life years saved per dollar spent.

The cooling parameters you can adjust are:

Street albedo: Target reflectivity for streets and parking lots. Albedo is defined in the range 0 (full absorption) to 1 (full reflectivity). Targeting a higher street albedo when repainting means more cooling and more larger reductions in mortality risk.
Rooftop albedo: Target reflectivity for rooftops. This works the same way as street albedo — a higher target albedo for rooftops means more cooling impact.
Albedo cooling rate: Temperature reduction (°C) per 0.1 increase in albedo. Values from other climate research range from 0.3 to 0.6. The higher the albedo cooling rate, the more effective repainting would be for reducing temperatures.

Once you've set all the parameters the way you'd like, click "Update Map" to calculate the results.

3. Explore the Map

In the County-Wide Results section under the control panel, you can see aggregated impacts of albedo cooling across the county for the parameter set you have chosen. If you input a budget constraint, the results will be limited to what is achievable under that budget. Otherwise, the county-wide results will show what is achievable by applying reflective coatings to all adaptable surfaces in squares where benefits exceed costs.

You can also hover over the map itself to see aggregated results for each neighborhood in the county (formally each CSA, or community statistical area). You will see a pop-up with information about the effects of albedo cooling on that specific area, such as what percentage of the neighborhood would be cost-effective to treat with reflective coatings, what is the average and maximum temperature reduction achievable across the squares in that neighborhood, or how many life years could be saved for residents of that neighborhood.

Enjoy!