In the early 1990s, heat waves battered Philadelphia’s most vulnerable communities. The lessons learned are helping today. (2023)

PHILADELPHIA — The water trickled down quickly, enough to coat the sun-bleached concrete basin in a city park with a layer of wetness. A toddler danced, smiling as water from the park’s sprinklers rained down on her, keeping her cool.

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It was a blistering midsummer day in July, the kind that as recently as 30 years ago would have proven disastrous for vast numbers of this city’s most vulnerable residents.

In the early 1990s, heat pounded Philadelphia’s most at-risk communities, killing or sickening scores. After a raft of changes, including the creation of an extensive heat warning system and opening “spraygrounds,” the city has been able to largely diminish the heat’s threat to its residents. And in a world where climate change is making extreme weather the norm, some say the city could be a model.


“We know climate change is here to stay,” said Drew Shindell, a professor of earth science at Duke University. “ … It’s still going to go on for decades, even if we take aggressive action. So it would make sense for more cities to adopt the kind of best practices the leading cities have put into place there.”

Philadelphia, largely bereft of greenery, faces hotter temperatures than more rural parts of Pennsylvania. The red-brick sidewalks and asphalt roadways that line the city’s landscape absorb more heat than natural foliage, creating a heat island effect.

Hot temperatures present a significant health risk, including the threat of heat stroke. When it’s hot, your heart rate climbs. The body kicks into overdrive, producing sweat to help itself cool down.

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The effectiveness of this physiological response can diminish with age, experts say. High heat and humidity, coupled with chronic illness, can be a dangerous — and potentially fatal — combination, particularly for older individuals and those with preexisting conditions.

“It’s very different when you’re on oxygen or you’re on a diuretic or heart medicine or, you know, you’re a smoker or have existing heart disease,” said Jay Lemery, an associate professor of emergency medicine at the University of Colorado School of Medicine. “At that point, you know, that physiological stressor is just enough to put you over into crisis.”

In summer 1993, Philadelphia reported 118 deaths, far more than other cities experiencing similarly sweltering conditions. Victims, many elderly and secluded, often weren’t found for hours or days. Some didn’t have air conditioning or had closed their windows at the time of their death, a potential indicator that heat may have played a role in exacerbating prior medical conditions, officials said.

“Nearly all of those deaths are preventable,” said Kristie Ebi, professor in the Center for Health and the Global Environment at the University of Washington.


At the time, most cities tended to label a death as heat-related only when signs of hyperthermia — when body temperature becomes abnormally high — were evident.

Philadelphia was an exception. Led by then-medical examiner Haresh Mirchandani, who pushed investigators to search for additional signs of heat exposure during periods of extreme heat, the city was able to get a more accurate reading of the impact heat was having in its communities.

Soon, other cities began to take notice. Using broader criteria to track heat-related deaths, investigators in Chicago found that the blazing heat that swept over the city during a three-day stretch in 1995 claimed the lives of 739 people. It was “exactly what happened in Philadelphia in 1993,” Mirchandani, now deceased, told the Chicago Tribune at the time.


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“With the Chicago heat wave of the ’90s, I think there was a recognition that, you know, urban heat could actually be really dangerous,” said Christine Knapp, director of Philadelphia’s Office of Sustainability. “I think there was a recognition that we could be in that kind of dangerous situation as well.”

Armed with a newfound understanding of the risks heat posed to its most vulnerable residents, Philadelphia officials sprang into action. The city implemented several strategies to insulate various communities from the threat of heat waves. In 1995, the city set up the Hot Weather-Health Watch/Warning System. The program provides the public with forecasts showing air mass projections. Air mass types linked with higher morbidity and mortality rates are noted, at which point the Philadelphia Department of Public Health steps in to provide emergency precautions and mitigation procedures for residents.

According to a 2004 report, such warnings save 2.6 people per day when issued. To date, the system has been implemented in more than 20 cities worldwide.

A public awareness campaign also sprouted in the aftermath of the scorching summers of the mid-1990s. Billboards paint downtown Philadelphia’s horizon, a constant reminder to residents of the risks attached to being outside in baking temperatures. Local news programs bombard Philadelphians with messages urging them to stay indoors during periods of excessive heat. Block captains and community organizers work to keep historically disadvantaged parts of the city abreast of changing climate projections.

“People need to be aware that heat is a killer,” Ebi said. “ … People need to understand that they have to pay attention, that they have to stay hydrated, that they find a way to keep cool.”

It’s an imperfect science, Shindell said. Climate change disproportionately affects low-income groups and people of color — both in this country and around the world. Neighborhoods such as Hunting Park, a Black and Hispanic enclave redlined heavily throughout the 20th century, face surface temperatures as much as 22 degrees higher than the largely White, grassier suburbs.

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Meanwhile, homelessness still affects a large portion of Philadelphia’s residents. According to a report by the city’s Office of Homeless Services, about 5,700 people were experiencing homelessness in 2019. That number is expected to rise with the end of covid-19 eviction moratoriums.


The city offers a host of services for residents seeking relief from the heat. There are 10 cooling centers, public spaces where vulnerable populations can find temporary relief from the sun’s gaze. Most are public libraries, Knapp said.

And during the coronavirus pandemic, with many libraries closed to the public, city officials got creative. Drawing on Philadelphia’s expansive bus system, SEPTA, climate and health experts helped create cooling buses. Parked on street corners across the city, the buses provide shade, comfort and cool air for those looking to beat the heat.

Spraygrounds also provide a temporary reprieve for children and their families on hot days. Young children are especially vulnerable to excessive heat conditions, a consequence of their underdeveloped physiological system, Ebi said.


It’s the sprinklers that draw the most attention, not the candy-color-painted slides and circuslike monkey bars. Children frolic under the mist, returning to their parents wet, weary and, most importantly, cool.

There is Seger Park, located in the area formerly known as Seventh Ward, a sleepy suburb that was once a cultural hub for Black and immigrant communities in the 19th and early-20th centuries. Once immortalized in W.E.B. Du Bois’ landmark study, “The Philadelphia Negro,” the area is now primarily White and upscale.

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Angel LeBron, 40, recently took his children, 23-month-olds Riley and Ajani, to the park. LeBron watched as Riley made her way around the playground. She stopped for a second, glancing at the streams of water converging in the middle.

She took a step closer, then another. Soon, she was sopping, unable to control her joy as water drenched her hair and T-shirt. LeBron, sitting on a cobalt blue bench with Ajani a few feet away, couldn’t stop laughing.


A longtime Kensington resident, LeBron has seen the increasingly unpredictable weather over the years. Precipitation patterns have proven more volatile, while the weather tends to stray between “super-duper hot” and “chillier” than what he’s experienced in the past.

Dustin Leyland, 42, agreed. Leyland lives about a block away from Starr Garden, another well-shaded sprayground located in the heart of Lombard Street.

A former Pittsburgh resident, Leyland has lived in Philadelphia since 2010.

“The summers are pretty similar, you know, very humid,” Leyland said. “You got to do something to keep cool.”

So, Leyland took his son, Berek, and his neighbor, Alex, to the park. A small building nearby is coated with streaks of bright yellow and forest-green paint. A mosaic of paper flowers shroud the metal “Starr Garden” sign emblazoned on the front.

The sprinkler appeared drab, in comparison. A murky mix of water, dirt and leaves pooled beneath the streams.

But Berek and Alex didn’t care. Equipped with bikes and helmets, the two circled around the pit for a few seconds. Then, they went in. They came out soaking and giggling as they peddled their way back to Leyland.

“It’s a great option. You know, especially [if] you don’t have … the place to, you know, use a hose or a sprinkler or something at their house,” Leyland said. “The only way they can do it is [to] get to the park.”


What are the social impacts of a heat wave? ›

Social impacts: Extreme heat can lead to heat-related illness and death, particularly in elderly populations, the poor, outdoor workers, and in urban areas.

What are the benefits of heatwave conditions? ›

Improves your mood. Sunlight does not only trip the release of serotonin but other hormones, known as endorphins, as well. These are associated with overall calm, less depression, and happier moods.

How does heat wave affect infrastructure? ›

Extreme heatwaves are pushing materials and equipment beyond their temperature thresholds. The vital infrastructure that modern society depends upon could buckle and even break as power lines, refrigeration units, roads, and rail lines simultaneously fail.

How can heat waves be prevented from the environment? ›

Installing cool and green roofs and cool pavement to reduce the urban heat island effect. Planting trees to provide shade and to cool the air through evapotranspiration. Pursuing energy efficiency to reduce demand on the electricity grid, especially during heat waves.

How heat waves affect the economy? ›

And beyond the immediate threat to life, extreme temperatures can impact economies, too. “Extended bouts of great heat can result in more hospital visits, a sharp loss of productivity in construction and agriculture, reduced agricultural yields, and even direct damage to infrastructure,” points out

How does hot weather affect humans? ›

Temperature Effects on Health

Temperature extremes most directly affect health by compromising the body's ability to regulate its internal temperature. Loss of internal temperature control can result in various illnesses, including heat cramps, heat exhaustion, heatstroke, and hyperthermia from extreme heat events.

Does a cold shower cool you down in hot weather? ›

Counterintuitive as it may seem, a cold shower may help to conserve body heat by causing blood vessels in the skin to constrict. This undermines one of the body's key strategies for heat loss: bringing blood closer to the skin's surface, so the heat can radiate out (hence why we look flushed when we are hot).

How can I keep my house cool in the heat? ›

10 tips to keep you and your house cool this summer
  1. Close your blinds. Keep your blinds closed, especially on north and west-facing windows, to significantly cool your home. ...
  2. Block the heat. ...
  3. Just 1oCmore. ...
  4. Adjust ceiling fans. ...
  5. Close doors and seal gaps. ...
  6. Hang out in the evening. ...
  7. Chill out, not chill on. ...
  8. Hack a fan.

Is hot weather Good For You? ›

Warmth and sunlight can offer real benefit to your health. From improved heart and lung health, to enhanced mental performance, living in a warm climate may give you just the health boost you need.

What are some solutions for heat waves? ›

Follow the tips below to help reduce the heat island effect and improve your community's resilience to heat waves.
  • Increase shade around your home. ...
  • Install green roofs. ...
  • Install cool roofs. ...
  • Use energy-efficient appliances and equipment. ...
  • Check on your friends, family, and neighbors.
21 Jul 2022

How can communities prepare for heat waves? ›

To improve resilience to future extreme heat events, cities can incorporate heat island reduction strategies—such as green or cool roofs, cool pavements, or increased vegetation and trees—into long-term planning efforts to help lower urban temperatures.

How are heat waves caused by climate change? ›

Unusually hot days and heat wave events are a natural part of day-to-day variation in weather. As the Earth's climate warms, however, hotter-than-usual days and nights are becoming more common (see the High and Low Temperatures indicator) and heat waves are expected to become more frequent and intense.

What safety considerations can be taken to prevent heat stress injuries? ›

Heat Stress
  • Drink small amounts of cool water frequently, regardless of your activity level. ...
  • Replace salt and minerals. ...
  • Wear appropriate clothing. ...
  • Protect yourself from the sun by wearing a wide‐brimmed hat. ...
  • Schedule outdoor work carefully. ...
  • Pace yourself.

What is causing the heat wave? ›

"As prevailing winds move the hot air east, the northern shifts of the jet stream trap the air and move it toward land, where it sinks, resulting in heat waves," the U.S. National Oceanic and Atmospheric Administration says on its website.

What are the effects of heat stress? ›

Heat stress can result in heat stroke, heat exhaustion, heat cramps, or heat rashes. Heat can also increase the risk of injuries in workers as it may result in sweaty palms, fogged-up safety glasses, and dizziness. Burns may also occur as a result of accidental contact with hot surfaces or steam.

What were the three main causes of death during the 2003 heatwave? ›

Sunburn - damage to the skin which can be painful and may increase the risks of getting skin cancer. Air pollution - it is thought that one third of the deaths caused by the heatwave in the UK were caused by poor air quality. Drowning - some people drowned when trying to cool off in rivers and lakes.

What countries are most affected by heat waves? ›

Currently, Spain, France, and Portugal are the countries most affected. In recent days, some areas of Spain have gotten as hot as 109ºF (43ºC). Spain hasn't seen temperatures this high in early June in 20 years or more.
Did You Know…?
  • climate crisis.
  • France.
  • heat waves.
  • India.
  • Pakistan.
  • Portugal.
  • Spain.
  • USA.
15 Jun 2022

How does temperature affect health? ›

The heart rate increases to pump more blood through outer body parts and skin so that excess heat is lost to the environment, and sweating occurs. These changes place additional demands on the body. Changes in blood flow and excessive sweating reduce a person's ability to do physical and mental work.

Is global warming good for us? ›

Yes, there will probably be some short-term and long-term benefits from global warming. For example, the flip side of increased mortality from heat waves may be decreased mortality from cold waves.

How do you survive a heat wave without air conditioning? ›

Here are 14 methods for doing so.
  1. Stay hydrated. ...
  2. Take a cold shower or bath. ...
  3. Use cold washrags on your neck or wrists. ...
  4. Use box fans. ...
  5. Close your curtains or blinds. ...
  6. Sleep in breathable linens. ...
  7. Install energy-efficient light bulbs. ...
  8. Cook in the morning, with a slow cooker or outside.
19 Jul 2022

How does temperature affect health? ›

Even small differences from seasonal average temperatures are associated with increased illness and death. Temperature extremes can also worsen chronic conditions, including cardiovascular, respiratory, and cerebrovascular disease and diabetes-related conditions. Heat also has important indirect health effects.

What temperature is too hot for humans? ›

People often point to a study published in 2010 that estimated that a wet-bulb temperature of 35 C – equal to 95 F at 100 percent humidity, or 115 F at 50 percent humidity – would be the upper limit of safety, beyond which the human body can no longer cool itself by evaporating sweat from the surface of the body to ...


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