Nick Lubecki has been an urban farmer in Pittsburgh for the past 15 years. The heat has noticeably intensified over that time, with back-to-back summers of sweltering temperatures affecting when he harvests produce at Braddock Farm, a small urban plot located next to an operating steel mill that grows vegetables such as lettuce, collards and tomatoes. His current strategy for beating the brutal heat: a wide-brimmed hat and lots of water. Lately, farming consistently throughout the day has been “significantly more exhausting,” he said. “It’s really hard to go on.”
Summers are getting hotter everywhere, and that’s especially true in cities including Pittsburgh, which has seen this year more than four times the number of days over 90 degrees Fahrenheit than it does in a typical year. This is partly due to the urban heat island effect, in which a city’s infrastructure traps heat, making it warmer than in neighboring suburbs. To combat the growing health risks for outdoor workers like Lubecki, scientists and designers are developing a range of new materials to combat extreme heat. But worker safety specialists and labor advocates worry that the commercialization of wearable technologies — even with the best intentions — could end up being aggravating existing problems with worker exploitation.
To cope with climate change and stay healthy outside, people need adaptations, and heat-reflective textiles have the potential to play a crucial role. Such solutions are “very important to not only show that there are some really cool technologies that come out of this need,” says Enrique Huerta, legislative director at Climate Resolve, a nonprofit that advocates for equitable climate solutions. but also that there is a need. to deploy it responsibly. It’s really, really important to highlight.”
What makes the urban heat island effect so dangerous is its cumulative nature. During the day, the built environment – concrete, asphalt, brick – readily absorbs the sun’s energy. At night, a city slowly releases all that built-up heat, keeping temperatures extra high until the morning. If you don’t have air conditioning and your body can’t cool down at night, and a heat wave continues day after day, the stress builds and builds. Nellie Brown, director of Workplace Health and Safety Programs at Cornell University, says that workers exposed to such conditions without relief are vulnerable to illnesses such as heatstroke, but in extreme cases can experience severe brain damage, kidney failure and even death.
In a recent report, Climate Central, a nonprofit that communicates climate science, studied the urban heat island index, or UHI, in 65 major U.S. cities to calculate how much the built environment raises temperatures. “The other big component … is population density, because we as humans create a lot of waste heat with our activities,” said Jennifer Brady, senior data analyst at Climate Central. “So cars, buses, trucks can create waste heat.” Of the 50 million people included in Climate Central’s analysis, 68 percent lived in areas with a UHI of 8 degrees or higher.
Lower-income neighborhoods also tend to be zoned for more industrial activity, with fewer trees and more asphalt and large buildings, all of which absorb and then radiate heat. This is especially dangerous if those workers live and sleep elsewhere in high-UHI neighborhoods, and they come to work after a night of still sweltering temperatures. This is where a substance that can relieve some of the physical symptoms of heat on the body can end up being a lifesaver.
Special textiles already exists to help cool a wearer by scattering direct sunlight away from the body or through emitting infrared radiation – which will come in handy when you’re out for a walk or, say, working in a backyard garden. A legion of American clothing companies produce clothing that helps mitigate the heat of direct sunlight, but those materials aren’t designed to offset the oppressive heat trapped in urban landscapes. In a city, the built environment also radiates heat from below, which presents an additional engineering challenge.
In June, researchers presented a clever new textile design that can indeed counteract the urban heat island effect. The top layer is made of plastic polymethylpentene, or PMP, fibers, which let in heat radiating from roads and buildings. Underneath that layer is silver nanowire, which is very good at reflecting that heat back through the PMP fibers and away from the body. Underneath, against the skin, is a layer of wool that acts as a buffer.
“It provides very good mechanical support because those PMP and silver nanowires are extremely thin,” says University of Chicago materials scientist Po-Chun Hsu, co-author of the new study. Just as a regular white shirt helps to bounce some of the sun’s energy away from the body, this new textile can deflect the heat coming from below, such as asphalt and city sidewalks.
But, as with any new product created to counter extreme heat and other climate impacts, there is the possibility of exploitation, said Dominique O’Connor, who works at the Farmworker Association of Florida. For example, the producers and contractors in charge of farms may “feel that they can push [workers] even harder or need less to give them breaks or water.”
Any heat-resistant clothing adopted by outdoor workers at the behest of their employer can also be a financial burden if they are expected to pay for it, according to O’Connor. Another concern is the issue of clothing care, as she doesn’t expect employers to offer laundry services for designated work clothes — she points out that many already don’t provide enough bathroom facilities or breaks — meaning workers will have to pay for multiple shirts themselves. or otherwise stuck cleaning the same item after each shift. This highlights the need for some sort of regulation to protect the abuse of such a solution, she said, although the likelihood of said regulation is low given the fact that a federal heat standard for workers still not finalized.
Some labor groups say that while such fabrics and materials can play a role in mitigating individual impacts of heat, such surface-level solutions should not be substituted for policy interventions that target the core problem: a lack of protection for workers against heat stress.
Nellie Brown at Cornell, which provides training and technical assistance on occupational safety and health issues, noted that tailoring any prospective material to what individual workplaces and jobs require should be the biggest safety consideration. All proposed solutions must go through the “hierarchy of controls,” Brown said — a method by the US Occupational Safety and Health Administration that identifies and ranks safety measures against workplace hazards.
Hsu likens the newly designed materials to the introduction of air conditioning, which has saved countless lives, especially as the world warms rapidly. “It has been proven to be an extremely big boost to people’s productivity, especially in tropical countries,” says Hsu. “Then you will run into the question of whether it will cause overwork. But I think that comes after you solve this heat stress or heat stroke issue.”
Although the textile that specifically targets the urban heat island effect is not yet on the market, other heat-repelling fabrics are. O’Connor’s team in Apopka, Florida, is considering continuing to invest in clothing already on the market to freely distribute to the farm workers they serve. The shirts, from a clothing company called Fieldsheer, are made with a brand of technology intended to mitigate a wearer’s body heat.
However, her colleague Jeannie Economos remains conflicted — will heat-fighting clothing be helpful, or end up creating more problems for outdoor workers, whether in the city or the field, many of whom already besieged by issues? “We were hesitant to buy it,” Economos said. “We don’t want to promote the shirts as some kind of miracle.”
Patrick Deighan, a spokesperson at Fieldsheer, told Grist that their fabric, made from a mix of recycled polyester and spandex and “infused with minerals,” effectively “draws moisture and heat from the skin and the body’s heat used to evaporate at a faster rate, which enhances the evaporative cooling effect, resulting in improved comfort and performance.” He noted that the line of shirts is designed to be used in multiple environments, including outdoors and indoors, and on the job, but did not comment on the concerns raised by Economos and other labor advocates.
Others, like Lubecki, are more open to the idea. “If it’s something that might help, I’ll give it a shot, if it’s any good,” he said. Still, he is cautiously optimistic and can’t help but wonder how accessible solutions such as heat-resistant workwear are for the agricultural workforce. “Honestly, like every year I hear about some new thing that someone is excited about. It’s supposed to make things cooler, and I don’t know, maybe it does. But the cost point has to make sense.”
