As a heat dome settles across the Southwest, the federal government and health departments across the country are emphasizing the importance of safeguarding against the impacts of extreme heat. Hospitals are preparing for potential surges in cases of acute heat-related illnesses including heat exhaustion and heat stroke. Healthcare providers also anticipate heat-related exacerbation of chronic conditions such as asthma, diabetes, and cardiovascular diseases.
While tornados and hurricanes may evoke greater fear, according to the Department of Health and Human Services’ (HHS’s) Office of Climate Change and Health Equity (OCCHE), heat is “the most lethal of all types of extreme weather.” Government efforts to address the health effects of extreme heat vividly highlight the complex challenge of achieving health equity. Not only can heat’s health impacts vary significantly within a single community, but this variation is frequently shaped by policies not immediately associated with healthcare. As summer heats up, we examine how the actions of even long-defunct government agencies continue to drive health outcomes.
Defining extreme heat
The lack of a universally accepted scientific definition of extreme heat invites the quip that “one knows it when one feels it.” It also adds to the confusion about heat-related policies. The Centers for Disease Control and Prevention (CDC) rather nonspecifically defines extreme heat as “summertime temperatures that are much hotter and/or humid than average.” In contrast, The Federal Emergency Management Agency (FEMA) is more exact, stating that “[i]n most of the United States, extreme heat is a long period (2 to 3 days) of high heat and humidity with temperatures above 90 degrees.”
While some heat-specific policies reference air temperatures, others refer to the “heat index.” The heat index, determined by a complex equation, approximates what the National Weather Service describes as “what the temperature feels like to the human body when relative humidity is combined with the air temperature.”
Heat in urban environments
A compelling example of how government policies can have lasting impacts on health equity, even after being denounced and abandoned, is evident in the impact of extreme heat in urban environments. Regrettably, the uneven distribution of heat island effects across urban neighborhoods can be traced back to discriminatory economic and housing policies of the past.
Heat islands form when urban development replaces natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat, increasing ambient temperatures compared to surrounding rural areas. Expanses of concrete and asphalt absorb heat, while the lack of green spaces deprives cities of the shade and the cooling effects of evapotranspiration provided by vegetation. Urban areas often experience higher temperatures than rural regions as a result. Additionally, buildings radiate absorbed heat at night, elevating nighttime temperatures. Nighttime heat can disrupt sleep patterns, which can hinder recovery from daytime heat exposure, exacerbating the health risks associated with extreme heat events.
Research has shown that the impact of extreme heat across major U.S. cities “is worse for both people of color and the poor, compared to white and wealthier populations.” Some of this disparity stems from past discriminatory practices that rendered more desirable neighborhoods inaccessible to minorities.
In the past, financial institutions denied loans and other financial services to applicants based on their racial and ethnic identity. Areas populated by African American, Hispanic, and other minority communities were often considered high-risk investments.
The practice of mapping these high-risk areas was known as “redlining” and was recognized by the federal government through official policies including those of the Home Owners’ Loan Corporation (HOLC). Long after the cessation of redlining, formerly redlined neighborhoods tend to have less green space and more concrete and asphalt than neighborhoods that were not redlined.
Turning up the AC
While heat islands illustrate policy legacies, access to and use of air conditioning demonstrates the influence of current, sometimes conflicting policies.
Less than a century ago, Americans considered air conditioning a luxury reserved for public spaces like movie theaters. Few had air conditioning in their homes, reflecting the prevailing view that it was primarily for comfort, rather than necessity, and that fans were sufficient for cooling. This attitude was exemplified by a U.S. War Production Board prohibition during World War II that banned the installation of air conditioning systems ‘solely for the purpose of personal comfort,’ underscoring the perception of air conditioning as a non-essential indulgence at the time.
Today, air conditioning has become a mainstay in American homes. According to the U.S. Department of Energy, “Three-quarters of all homes in the United States have air conditioners.” Another federal agency, the U.S. Energy Information Administration (EIA) estimates that nearly 90% of American homes used some form of air conditioning at some point in 2020 and that two-thirds had access to central air conditioning.
From a healthcare perspective, air conditioning is no longer regarded as a matter of personal comfort. The use of central air conditioning has been shown to reduce the health risks associated with higher temperatures. And there are no effective alternatives as health experts advise “against the use of fans in very hot conditions, especially for individuals with reduced physiological capacity to respond to temperature extremes.” In an ironic twist on previous beliefs, the CDC cautions that fans “provide comfort… but won’t prevent heat related illness.”
Access to air conditioning can depend on several factors, including where one lives. State policies on air conditioning do not necessarily align with temperature maps or latitude. Oregon, for example, has garnered significant attention this year for including air conditioning as a covered benefit under its Medicaid waiver. The state has also passed laws allowing tenants to install air conditioning units. For some, these measures represent a governmental overreach; for those on the other side of the argument, it is an informed response to recent extreme heat events.
Oregon Medicaid is the exception, and most Americans are not guaranteed access to air conditioning equipment under their health insurance plans. Air conditioning is not covered under traditional fee-for-service Medicare, but some Medicare Advantage plans offer coverage for qualifying patients. Other plans may offer a compromise: In 2022, Cigna announced that enrollees in its Medicare Advantage programs could use their transportation benefit for rides to air-conditioned community cooling centers during extreme heat events.
Of course, air conditioning depends upon the availability of energy, and this is not always guaranteed. During periods of extreme heat, the surge in electricity consumption can overwhelm power infrastructure, resulting in both spontaneous and planned or rolling blackouts. Adding another layer of complexity, in an effort to reduce legal liability, power companies are increasingly inclined to turn off power to transmission lines when extreme heat is accompanied by high winds and increased fire danger. (Again, we observe the unintended consequences of well-meaning policies. The heightened risk for catastrophic and deadly wildfires in certain parts of the country can be linked to the U.S. Forest Service’s historical policy of total wildfire suppression, famously represented by the Smokey Bear campaign.)
Whatever their causes, power outages have impacts beyond disrupting air conditioning. Blackouts also pose problems for those who rely on electrically powered medical or mobility equipment, such as oxygen concentrators and power wheelchairs. Accessing backup power sources or batteries for essential electric medical equipment during power outages can be a greater challenge for patients with limited financial resources.
Even when power to run air conditioning is available, some individuals may not be able to afford it. The Low-Income Home Energy Assistance Program (LIHEAP) acknowledges that for many families, summer means making “the difficult choice between paying for home cooling or paying for family essentials such as food or medical care.” The program helps low-income households afford cooling during extreme heat by assisting with energy costs and providing grants for air conditioning units and other generators.
The availability of LIHEAP resources varies by location, and the program does not guarantee immediate aid. When families cannot pay an existing electric bill, they face the possibility that their utility provider may disconnect their service. The potential for disconnection during a heat wave depends upon the consumer protection policies in their state of residence. While most states have laws prohibiting the disconnection of utilities during periods of extreme cold, not all extend the same protections during heat events. The specific temperature thresholds and criteria for disconnection protections vary widely among states.
For example, under Minnesota’s summer disconnect protection, “a utility may not effect an involuntary disconnection of residential services in affected counties when an excessive heat watch, heat advisory, or excessive heat warning issued by the National Weather Service is in effect.” Georgia prohibits a utility from disconnecting power when the temperature is at or above 98°F. Delaware uses a heat index measurement to prohibit disconnections.
During wildfire smoke events, state or local health departments may specifically advise against the use of some air conditioning regardless of temperature. Although wildfire activity in the U.S. in 2023 was lower than the ten-year average, close to 100 million Americans were subject to smoke advisories in June 2023 because of unusual fire activity in Canada. While certain air conditioning equipment can effectively filter particulate matter from the air, other types funnel it indoors. Wildfire smoke brings the risk of eye and respiratory tract irritation, with greater impact on vulnerable populations, including the very young, the elderly, and those with chronic diseases.
Regulatory reform of air conditioning
It is impossible to consider air conditioning separate from emerging climate policies.
Air conditioning equipment manufactured before the late 1980s was largely dependent upon chlorofluorocarbons (CFCs) as refrigerants. However, CFCs were later linked to the depletion of the Earth’s ozone layer, which shields the planet from harmful ultraviolet radiation. This realization led to an international consensus on the need to address ozone depletion, culminating in the Montreal Protocol in 1987.
Notably, the Montreal Protocol was ratified unanimously by the U.S. Senate, reflecting a bipartisan recognition of the environmental threat posed by CFCs. President Reagan, who had previously battled skin cancer, acknowledged ozone depletion as a global problem requiring a global solution.
Since the finalization of the Montreal Protocol, CFCs have been phased out and replaced with hydrofluorocarbons (HFCs) in air conditioning systems. While HFCs are less damaging to the ozone layer, they are potent greenhouse gases associated with climate change.
To address this issue, the Environmental Protection Agency has taken action to phase down the use of HFCs under the American Innovation and Manufacturing (AIM) Act of 2020. The AIM Act establishes a phase-down schedule for the production and consumption of HFCs, aiming to reduce their use by 85% over the next two decades.
However, there are concerns that the phase-out of HFCs and transition to alternative refrigerants could drive up the cost of air conditioning systems. Critics, such as the Competitive Enterprise Institute, a free-market advocacy group, argue that the new regulations may “skew the market towards pricier products,” potentially making the purchase of new air conditioning equipment unaffordable for many consumers.
Without targeted assistance programs or consumer protections, the shift to environmentally friendly refrigerants could unintentionally worsen existing disparities in access to cooling during extreme heat events.
The challenge
Addressing the health impacts of extreme heat is a multifaceted challenge that requires navigating a web of intertwined and sometimes conflicting policies. Historical practices have disproportionately affected marginalized communities, leaving them facing higher temperatures and fewer resources.
Efforts to transition to more sustainable cooling technologies highlight the tension between environmental goals and immediate public health needs, underscoring the importance of carefully balancing these priorities to avoid exacerbating existing inequities.
Ultimately, achieving health equity in the face of extreme heat requires a holistic approach that considers the historical, economic, and environmental dimensions of the issue. Policymakers, healthcare providers, and community leaders must work together to develop comprehensive strategies that address both the root causes and immediate impacts of extreme heat, ensuring that all communities have the resources and support they need to stay safe and healthy.