Climate Health and Equity

May 17, 2023

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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.

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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. 

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Exposure

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.

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Access 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

Graph that shows the rate of air conditioning ownership by metropolitan statistical area. Most cities boast about 95% ownership. San Francisco's is around 40%.


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.


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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.


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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 


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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.

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. 


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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


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Sensitivity

Two people in the same room or building may experience extreme heat differently based on their physiological sensitivity to the hazard.

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Older 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


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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.


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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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Pregnancy

Pregnancy during wildfires is associated with pre-term birth weight, pre-term birth, gestational diabetes, gestational hypertension.24 


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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.

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Race 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


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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


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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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Citations

1. Moore, S. San Francisco is now the least air-conditioned city in the country. San Francisco Chronicle. January 2, 2023. Retrieved from: https://www.sfgate.com/local/article/san-francisco-lacks-air-conditioning-17685873.php
2. U.S. Census Bureau. 2021 Top 15 Metropolitan Areas—Heating, Air Conditioning, and Appliances—All Occupied Units, Units with Primary Air Conditioning. 2021 American Housing Survey. Retrieved from: https://www.census.gov/programs-surveys/ahs/data/interactive/ahstablecreator.html?s_areas=00100&s_year=2021&s_tablename=TABLE3&s_bygroup1=30&s_bygroup2=1&s_filtergroup1=1&s_filtergroup2=1
3. California Air Resources Board. Protecting Yourself From Wildfire Smoke: Smoke Ready California Retrieved from: https://ww2.arb.ca.gov/protecting-yourself-wildfire-smoke
4. About Urban Heat Islands, National Integrated Heat Health Information System (NIHHIS). Retrieved fromhttps://www.heat.gov/pages/urban-heat-islands
5. Wilson, B. Urban Heat Management and the Legacy of Redlining. Journal of the American Planning Association. (2020). Retrieved from: https://www.tandfonline.com/doi/full/10.1080/01944363.2020.1759127
6. Rahman, M., McConnell, R., Schlaerth, H., Ko, J., Silva, S., Lurmann, F., Palinkas, L., Johnston, J., Hurlburt, M., Yin, H., Ban-Weiss, G., Garcia, E. The Effects of Coexposure to Extremes of Heat and Particulate Air Pollution on Mortality in California: Implications for Climate Change. (2022). American Journal of Respiratory and Critical Care Medicine. Retrieved from: https://www.atsjournals.org/doi/abs/10.1164/rccm.202204-0657OC?role=tab
7. San Francisco Planning. Air Quality Community Risk Reduction Plan. Retrieved from: https://sfplanning.org/air-quality-community-risk-reduction-plan#info
8. San Francisco Planning. Environmental Justice Framework and General Plan Policies. Retrieved from: https://sfplanning.org/project/environmental-justice-framework-and-general-plan-policies
9. Chabria, A., Smith, E. Column: Could extreme heat be just what California needs to finally solve homelessness? Los Angeles Times. September 13, 2022. Retrieved from: https://www.latimes.com/california/story/2022-09-13/extreme-heat-climate-change-california-homeless-shelter-housing-policy
10. Schwarz, L., Castillo E., Chan, T., Brennan, J., Sbiroli, E., Carrasco-Escobar, G., Nguyen, A., Clemesha, R., Gershunov, A., Benmarhnia, T., Heat Waves and Emergency Department Visits Among the Homeless, San Diego 2012-2019. American Journal of Public Health. September 18, 2021. Retrieved from: https://ajph.aphapublications.org/doi/10.2105/AJPH.2021.306557
11. Abbinett, J., Schramm, P., Widerynski, S., Saha, S., Beavers, S., Eaglin, M, Lei, U.,, Nayak, S., Roach, M., Wolff M., Conlon K., and Thie, L. (2020) "Heat Response Plans: Summary of Evidence and Strategies for Collaboration and Implementation." Climate and Health Technical Report Series Climate and Health Program, Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/climateandhealth/docs/HeatResponsePlans_508.pdf.
12. Knowlton, K., Rotkin-Ellman, M., King, G., Margolis, H., Smith, D., Solomon, G., Trent, R., and English, P., The 2006 California Heat Wave: Impacts of Hospitalizations and Emergency Department Visits. Environmental Health Perspectives. August 22, 2008. retrieved from: https://pubmed.ncbi.nlm.nih.gov/19165388/
13. How to Stay Hydrated for Better Health. National Council on Aging. August 23, 2021. Retrieved from: https://www.ncoa.org/article/how-to-stay-hydrated-for-better-health
14. Protecting Children’s Health During and After Natural Disasters: Extreme Heat. Environmental Protection Agency. Retrieved from: https://www.epa.gov/children/protecting-childrens-health-during-and-after-natural-disasters-extreme-heat
15. Ebi, K. L. et al. Hot weather and heat extremes: health risks. Lancet (2021). Retrieved from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01208-3/fulltext
16. Pathak, Neha. Common medications may increase dangers of heat waves. Yale climate connections. July 26, 2022. Retrieved from: https://yaleclimateconnections.org/2022/07/common-medications-may-increase-the-dangers-of-heat-waves/
17. Bunker, A., Wildenhain, J., Vandenbergh, A., Henschke, N., Rocklöv, J., Hajat, S., & Sauerborn, R. Effects of air temperature on climate-sensitive mortality and morbidity outcomes in the elderly; a systematic review and meta-analysis of epidemiological evidence. EBioMedicine. 2016. Retrieved from: https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(16)30073-1/fulltext
18. Semenza JC, Rubin CH, Falter KH, Selanikio JD, Flanders WD, Howe HL, Wilhelm JL. Heat-related deaths during the July 1995 heat wave in Chicago. New England Journal of Medicine. 1996. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/8649494/
19. Wettstein, Z., Hoshiko, S., Fahimi, J., Harrison, R., Cascio, W., Rappold, A.. Cardiovascular and Cerebrovascular Emergency Department Visits Associated with Wildfire Smoke Exposure in California in 2015. Journal of the American Heart Association. April 11, 2018. Retrieved from: https://www.ahajournals.org/doi/10.1161/JAHA.117.007492
20. Anderson GB, Dominici F, Wang Y, McCormack MC, Bell ML, Peng RD. Heat-related emergency hospitalizations for respiratory diseases in the Medicare population. Am J Respir Crit Care Med. 2013. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3734617/
21. Reid, C., Brauer, M., Johnston, F., Jerrett, M., Balmes, J., Elliott, C. Critical Review of Health Impacts of Wildfire Smoke Exposure. Environmental Health Perspectives. September 1, 2016. Retrieved from: https://ehp.niehs.nih.gov/doi/10.1289/ehp.1409277
22. Managing Diabetes in the Heat. Centers for Disease Control. Retrieved from: https://www.cdc.gov/diabetes/library/features/manage-diabetes-heat.html
23. Nori-Sarma, A., Sun, S., Sun, Y. Association Between Ambient Heat and Risk of Emergency Department Visits for Mental Health Among US Adults, 2010 to 2019. Journal of the American Medical Association, Psychiatry. February 23, 2022. Retrieved from: https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2789481
24. Heft-Neal, S., Driscoll, A., Yang, W., Shaw, G., Burke, M. Associations between wildfire smoke exposure during pregnancy and risk of preterm birth in California. Environmental Research. January 2022. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/34403668/
25. Gronlund, C.., Racial and socioeconomic disparities in heat-related health effects and their mechanisms: a review. Curr Epidemiol Rep, 2014. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4264980/
26. Kahtana, S., Werner, R., Groeneveld, P., Associate of Extreme Heat With All-Cause Mortality in the Contiguous US, 2008-2017. Journal of the American Medical Association. May, 19, 2022. Retrieved from: https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2792389
27. Naughton, M. Henderson, A. Mirabelli, M., Kaiser, R., Wilhelm, J., Kieszak, Stephanie, Rubin, C., McGeehin, M. Heat-related mortality during a 1999 heat wave in Chicago. American Journal of Preventative Medicine. 2002. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/11988377/
28. Vasquez, K. Worsening heat waves are hammering the disabled community. (2021). Environmental Health News. November 11, 2021. Retrieved from: https://www.ehn.org/heat-waves-disabled-community-2655520353.html
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