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Visualize how extreme heat and wildfire smoke exposure, sensitivity, and adaptive capacity differs neighborhood to neighborhood, and community to community in San Francisco.
- Climate Change, Health, and Equity
- Exposure
- Access to Cooling
- Urban Heat Islands
- Air Pollution Exposure
- Environmental Justice Neighborhoods
- Marginally Housed or Unhoused Populations
- Sensitivity
- Older Adults
- Children
- People with Pre-Existing Health Conditions
- Pregnancy
- Adaptive Capacity
- Race and Ethnicity
- Social Isolation
- Disability
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- Citations
Sections
- Climate Change, Health, and Equity
- Exposure
- Access to Cooling
- Urban Heat Islands
- Air Pollution Exposure
- Environmental Justice Neighborhoods
- Marginally Housed or Unhoused Populations
- Sensitivity
- Older Adults
- Children
- People with Pre-Existing Health Conditions
- Pregnancy
- Adaptive Capacity
- Race and Ethnicity
- Social Isolation
- Disability
- Back to the Climate and Health Home Page
- Citations
Climate Change, Health, and Equity
While the health impacts of extreme heat and wildfire smoke affect everyone, not everyone will be impacted evenly. The inequitable distribution of health impacts is referred to as the climate gap.
Certain communities will be particularly impacted based on:
- Their exposure to the hazard
- Their physical sensitivity to the hazard
- Their ability to adapt to the hazard—to have access to the economic, political, and social resources to be resilient.
This section will define exposure, sensitivity, and adaptive capacity and provide examples about how specific factors make someone more vulnerable to the health impacts of extreme heat. Please check out our visualization page to explore how these exposure, sensitivity, and adaptive capacity indicators intersect with San Francisco's communities and neighborhoods.
Back to topExposure
Exposure to extreme heat and wildfire smoke can vary from building to building and neighborhood to neighborhood. San Francisco is a historically temperate City with homes, businesses, schools, and municipal buildings largely built for cool coastal temperatures and predictable afternoon marine layer. San Francisco’s fog and mountains give the city microclimates, which can lead to wide temperature and air quality variations between neighborhoods on the City’s western and eastern sides.
Back to topAccess to Cooling
San Francisco's homes are the least likely in the United States to be air conditioned.1 Air conditioning ownership is not equitable, and wealthier San Franciscans are more likely to have access to cooling in their homes. Older buildings, including Single Room Occupancy Hotels (SROs) may be especially vulnerable to overheating, and built without the electrical load capacity to sustain many upgrades. Many of San Francisco’s schools and healthcare facilities are also without adequate cooling. Extreme heat events may impact access to these services. The chart below from the American Housing Survey shows data for air conditioning ownership for each of the 15 largest Metropolitan Statistical Areas.2
Access to Ventilation
Like access to cooling, San Francisco's housing and built environment was largely developed for regular afternoon winds that provide cool and clean air. San Franciscans with the greatest sensitivity to pollution may not be able to access the buildings with adequate filtration to limit intrusion of wildfire smoke. The California Air Resources Board has developed low-cost recommendations to develop clean air spaces within your home.3
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Urban Heat Islands
Vulnerability to heat can also be heavily driven by the urban heat island effect. Urban areas can be as much 15°F-20°F hotter than adjacent rural areas counterparts because their pavement and other impervious surfaces absorb heat, their skyscrapers and other large buildings can block wind, and they often lack trees and other green infrastructure that can provide shade.4 The distribution of green space and tree coverage in cities is influenced by the legacy of racist policies such as redlining that institutionalized disinvestment in communities of color for much of the 20th century into today.5 In San Francisco, the warmest neighborhoods are often located in the central, southern and eastern portions of the City.
Air Pollution Exposure
Neighborhoods and communities adjacent to industrial sites, high-traffic roads, and other point source emissions are disproportionately impacted by air quality year-round. The combined health impact of extreme heat and air pollution is especially dangerous.6 In San Francisco, the Article 38 Exposure Zone (APEZ) map identifies communities with the largest air pollution burden and requires enhanced ventilation in new construction in those communities.7
Environmental Justice Neighborhoods
The San Francisco Planning Department defines environmental justice as "the equitable distribution of environmental benefits and the elimination of environmental burdens to promote healthy communities where all San Franciscans can thrive. Government can foster environmental justice through processes that address, mitigate, and amend past injustices while enabling proactive community-lead solutions". Environmental Justice communities are disproportionately impacted by not only environmental burdens, but many stressors including racism, displacement, food insecurity, and health impacts.8
The San Francisco Environmental Justice Communities Map identifies Bayview Hunters Point, Chinatown, Excelsior, Japantown, Mission, Ocean View-Merced Heights-Ingleside, Outer Mission, Potrero Hill, SoMA, Tenderloin, Treasure Island, Visitacion Valley, and Western Addition as Environmental Justice Communities.
Marginally Housed or Unhoused Populations
Unsheltered or marginally sheltered populations are vulnerable to the health impacts of extreme heat because they are disproportionately exposed, are likely to have pre-existing physical or mental health conditions, and lack the resources necessary to prepare for or respond to extreme weather events.9 Homeless individuals face barriers to accessing cooling centers or other air conditioned spaces, especially if these spaces prohibit pets, food, or other possessions. Researchers found that, during extreme heat events in San Diego, homeless individuals significantly were more likely to end up in the hospital compared to non-homeless individuals.10
Sensitivity
Two people in the same room or building may experience extreme heat differently based on their physiological sensitivity to the hazard.
Back to topOlder Adults
Older adults are among the most vulnerable to the health impacts of extreme heat, largely because of health conditions that come with the process of aging.11 During the 2006 California heat wave, older adults showed a greater risk of heat related hospitalizations particularly those with diabetes, cardiovascular disease, and respiratory illnesses.12 Older adults are also at a greater risk for dehydration because of a reduced sense of thirst and a higher likelihood of taking medication that may cause increased urination or perspiration.13
Children
Children are also vulnerable to the health impacts of extreme heat.14 Small children both absorb more heat and more easily overheat as they have a comparatively high surface area to body mass ratio. Children also have decreased sweating capacity and can be slow to recognize the signs of heat-related illnesses.
People with Pre-Existing Health Conditions
People of all ages with pre-existing health conditions are vulnerable to extreme heat. Pre-existing health conditions that have been linked to extreme heat vulnerability include cardiovascular illness, respiratory illnesses and asthma, diabetes and renal failure, and those on specific medications that may become ineffective or dangerous in extreme temperatures.15,16
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Cardiovascular disease is the primary cause of death during heat waves.17 Of the estimated 700 excess deaths during a 1995 Chicago heat wave, 39% had prior heart conditions.18 A 2018 study analyzed ED visits during the 2015 wildfires in Northern and Central California and found that on days with more wildfire smoke, there were more emergency department visits for numerous cardiovascular disease outcomes.19
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Many studies have demonstrated the relationship between temperature, air quality, and respiratory illness.20 COPD hospitalizations, emergency department visits, and physician visits increase after exposure to wildfire smoke.21
- Populations with diabetes account for a significant number of hospitalizations during extreme heat events.22
- Extreme Heat can exacerbate mental health conditions. Studies have found that both the number of deaths and emergency department visits for mental health emergencies have been associated with extreme heat events.23
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Pregnancy
Adaptive Capacity
Adaptive capacity refers to a person or community’s ability to prepare for, respond to, or recover from extreme heat or wildfire smoke events. Adaptive capacity is largely influenced by person’s access to economic, social, and political resources. Communities with greatest adaptive capacity are able to purchase cooling equipment, rely on social networks if there is any disruption in transportation, healthcare, and other emergency services, and are better able navigate and utilize government resources and communications channels. Specific factors that influence adaptive capacity include race, income, educational attainment, immigration status, language access, physical and cognitive disability, and social isolation.
Back to topRace and Ethnicity
Race and ethnicity are associated with morbidity and mortality to extreme heat.25 Because generations of systemic discrimination, Black African American families are more likely to live in urban heat islands away from green infrastructure, adjacent to point-source pollution, industrial activities, and other environmental burdens, and in housing without cooling. Partially because of these exposures, these families have disproportionally high rates of co-morbidities such as diabetes, cardiovascular illness, and asthma. Research suggests that, between 2008 and 2017, non-Hispanic Black individuals had a greater increase of all-cause mortality during extreme heat events than other races.26
Social Isolation
Social isolation refers to the quantity and quality of relationships with family, friends, and formal and informal networks. Social isolation can be a function of physical isolation (i.e. living alone), chronic health conditions, linguistic isolation, or other contributing factors. An analysis of a 1995 Chicago heat wave found that populations who lived alone were at increased risk for heat-related morbidity and mortality.27 An analysis of a 1999 Chicago heat wave identified living alone and not leaving the home daily as the most important risk factors for heat-related death.28
Disability
People with physical, cognitive, and sensory disabilities are vulnerable to the health impacts of extreme heat and wildfire smoke.29 These communities may be vulnerable because they have physiological sensitivities to the hazards, are taking medicines such as diuretics, that impacts thermoregulation, and/or because there are barriers to accessing emergency preparedness and response resources.
Any power disruption associated with an extreme heat event may impact people who rely on electricity-dependent durable medical and assistive equipment and devices, or people who have mobility disabilities and are dependent on elevators.
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