How San Francisco is tackling extreme heat and air quality

temperatures. The city has the lowest rate of air conditioning in the US. A statement from the City said evidence suggests that San Francisco’s emergency department visits, hospitalisations, and deaths begin to increase when the temperature reaches above 85 degrees.

Between 1961 and 1990, San Francisco experienced an average of three and a maximum of 10 days a year of extreme heat, classified as any day over 85 degrees. The state projects those numbers to more than double by the mid-century (2035 – 2065), to an average of seven and a maximum of 24 days, and to double again by the late century (2070 – 2099), to an average of 15 and a maximum of 51 days a year of extreme heat. That heat will not be felt equally across the City.

Data visualisation

Data visualisations released by the Department of Public Health reveal the distribution of indicators, including age, tree density, and population with existing health conditions, across the City. Access to cooling and ventilation, being unhoused, and living in a neighbourhood with more air pollution or higher temperatures influence a person’s exposure to heat and wildfire smoke.

To create the plan, the Office of Resilience and Capital Planning, the Department of Public Health, and the Department of Emergency Management convened 23 City departments, 11 community-based organisations, and experts from UCSF and UC Berkeley. The result was 31 strategies designed to create a San Francisco that is more resilient to extreme heat and wildfire smoke, particularly for communities that bear the greatest public health burden.

“This plan lays out bold, aggressive action because our future depends on it, and San Franciscans need to know how the City is planning to be more resilient and prepared in response to environmental challenges”

“This implementation plan provides specific strategies to protect our most vulnerable residents from extreme heat and poor air quality,” said Brian Strong, chief resilience officer and director of the Office of Resilience and Capital Planning.

“First, we identified what are the barriers. For example, we know non-profits and owners of low-income housing face a number of obstacles to equip their buildings with sufficient cooling and air filtration systems in a changing climate. Then, we looked for opportunities.

“It’s so important that we get this right. If we do, we can adapt San Francisco’s buildings, infrastructure, and natural environment to reduce exposure to extreme heat and poor air quality, protect the health of our most vulnerable residents, and make San Francisco more resilient to climate-related stressors.”

Eight of the 31 strategies outlined in the plan are ongoing and already in progress by City departments. They include:

• Establishing priority development zones for green infrastructure focused on heat and air quality resilience, using health, environment, and exposure data, and augmenting existing tree plantings in these areas
• Standardising collection and dissemination of data across City departments to support the development of green infrastructure and reduce urban heat islands. Urban heat islands are areas that are much hotter than surrounding areas due to their concentration of pavement, buildings, and other surfaces that absorb and retain heat.
• Identifying City and community facilities that will form the network of short, medium, and long-term respite locations open to the public for extreme heat, air-quality events, and other emergencies
• Strengthening and supporting neighbourhood hubs that bring together community-based organisations, businesses, and resourcing locations to create and implement neighborhood-specific emergency mitigation, preparedness, and response plans
• Activating a community branch of the City’s emergency operations centre to be a conduit for community partners during extreme heat and wildfire smoke events.

Future strategies include:

• Cooling and clean air pilot projects in a range of building types to identify best practices, including multi-unit, affordable, and supportive housing
• Developing heat and air quality design guidelines for new buildings as well as retrofit and rehabilitation projects
• Facilitating a citywide work group of agencies to identify the services necessary to support respite centres and facilitate their use, establish roles and responsibilities, and plan to scale services at various activation thresholds
• Piloting a wellness check programme for community-based organisations and City departments serving vulnerable populations, including homebound seniors and people with access and functional needs
• Establishing a public-facing online tool to connect residents to local, state, and federal home weatherisation and cost-assistance resources
• Developing public education initiatives to connect benefits of green infrastructure to public health and communicate the full range of benefits of tree canopy expansion.

The plan builds upon Mayor London N. Breed’s 2018 Executive Directive on air quality incidents and existing citywide climate resilience and mitigation strategies, including the San Francisco Climate Action Plan and 2020 Hazards and Climate Resilience Plan.