By Ysabelle Kempe for Smart Cities Dive.
Broadcast version by Suzanne Potter for California News Service reporting for the Solutions Journalism Network-Public News Service Collaboration

Reflective pavement coating helped cool down one of Los Angeles' hottest neighborhoods over a year-long period, according to a recently published study in Environmental Research Communications, but some researchers argue in favor of increasing shade as a better way to protect people from dangerously high temperatures.

The research on the installation in LA's Pacoima neighborhood is "probably the most comprehensive study on controlled cool pavement" due to the large amount of data and variables considered, said Haider Taha, an atmospheric modeler, president of the research company Altostratus and the study's author.

Over 700,000 square feet of dark asphalt surfaces in Pacoima were covered with solar-reflective pavement coating in the summer of 2022 through a partnership between local nonprofit Climate Resolve and roofing and waterproofing manufacturer GAF, which provided the coating.

Pavement that reflects, rather than absorbs sunlight, has emerged as a tool cities are considering to mitigate theincreasing danger of extreme heat.

GAF funded the recently released peer-reviewed study, although the company had no role in the study's design, data collection, modeling or analysis of the results. The research found that during an extreme heat event, the cool pavement-covered area saw ambient air temperatures that were as much as 3.5 degrees Fahrenheit cooler than those in the adjacent neighborhood. On sunny days, ambient air temperatures were reduced by up to 2.1 degrees Fahrenheit. During summer nights, they were reduced by up to 0.5 degrees Fahrenheit. The coating also lowered surface temperatures by up to around 10 degrees Fahrenheit.

What does that mean for the people who live in Pacoima? Melanie Torres, a resident and the Pacoima Beautiful's Cool Community Project organizing manager, said she's felt a difference. Pacoima Beautiful is a local environmental justice organization and helped GAF and Climate Resolve with community engagement for the reflective pavement project.

Torres often eats lunch in one of the parks where the coating is deployed. "I can just sit on the grass near the basketball court and feel just the breeze - and not necessarily a hot breeze," she said. A food vendor who frequents the neighborhood told Torres that "she feels the difference in the breeze more than anything.

Torres said she hasn't heard any complaints about the reflective pavement coating during her community engagement efforts. However, reflective pavement is not immune to criticism.

Some researchers have found that the solar energy reflected off cool pavement can actually increase how hot pedestrians feel. Taha, however, said that his study indicated an "improvement in thermal sensation," noting that every location within Pacoima has "its own dynamics" that could lead to slightly different results. Mean radiant temperature - a measurement of thermal comfort - "goes up and down. It's not always cooler," he said. "The overwhelming effect is the cooling."

But no matter how effective reflective coatings are, they can't beat shade, V. Kelly Turner, associate director of the University of California, Los Angeles' Luskin Center for Innovation and an associate professor of urban planning and geography, said in an email. Shade can cool people by up to 30 degrees Celsius, or 54 degrees Fahrenheit, in hot, dry environments, she said.

"No change in surface will protect the body from heat as effectively as preventing sunlight from hitting the body in the first place," she said. "Shade - blocking the sun with trees, canopies, and tall features like walls and buildings - is by far the most effective way to cool people outdoors."

She noted that reflective pavement doesn't have a large effect on air temperature unless it is deployed widely and, even when that happens, the cooling benefit is moderate. She believes that reflective pavement is an appropriate choice in locations where it would be difficult to replace surfaces that absorb a lot of heat with "something else like vegetation and where the goal of mitigating surface material contributions to heat is the priority as opposed to protecting people's bodies outdoors."

"I think cities should see reflective pavement as one tool among many, if deployed comprehensively, that could mitigate the regional urban heat island," Turner said. "They should see this goal as parsimonious from the public health goal of protecting people's bodies from the sun."


Ysabelle Kempe wrote this article for Smart Cities Dive.


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Environmental groups in Texas are backing a proposed global plastics treaty set to be finalized by the end of the year.

The treaty aims to minimize plastic's effect on the environment and make manufacturers responsible for managing plastic waste. The treaty also encourages the use of reusable options, such as single-use bags, straws and utensils.

Cheyenne Rendon, senior policy officer for the Society of Native Nations, said supporters need to focus on the people the treaty will serve.

"The United States has already conveyed that they're not willing to operate out of current existing laws," Rendon pointed out. "Although their approach is, they are for the global plastics treaty, it's at the lowest denomination of a treaty as possible. So that's why we have to lead with this with a human-based approach. How are we going to take care of not only our planet, but our people?"

Texas is one of the largest producers of fossil fuels and plastic in the nation, with most coming from the Houston Ship Channel. It is the second-largest petrochemical complex in the world and surrounded by low-income communities of color. People in the area have life expectancies up to 20 years shorter than those in white communities just 15 miles away.

Amnesty International recently deemed the Houston Ship Channel a "sacrifice zone," meaning residents suffer devastating physical and mental health consequences, along with human rights violations from living in pollution hotspots.

Yvette Arellano, founder of the group Fenceline Watch, said they have promoted environmental change at the local and state levels for years. They argued by backing the plastics treaty, they are taking their concerns nationally and globally.

"We're in collaboration with over 300 other organizations, from grassroots to academics and legal organizations," Arellano explained. "Trying to uplift the severe human rights violations that petrochemical companies and the fossil fuel industry, along with false solutions they're bringing along."

Arellano added there is no way for people living in the area to escape the poison.

"Whether we are at home, outside gardening or spending leisure time with family, whether we're at school at the grocery store, at the post office," Arellano outlined. "We're consistently and continuously being poisoned with full and free license to, on behalf of our regulatory agencies."

The groups will testify at the United Nations later this year.


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Hurricane season is here, and conservationists are shining a light on the role salt marshes play in protecting coastal North Carolina communities.

Studies find that salt marshes absorb flood waters and wave energy, reducing property damage in nearby areas by an average 20%.

Charlie Deaton, a habitat protection biologist at the North Carolina Division of Marine Fisheries, explained what salt marshes do to help areas build climate resilience.

"They're good at helping us actually mitigate some of the carbon we've released into the atmosphere, and they are good for community resilience, too," he said. "They protect landward shorelines from erosion, and salt marshes' larger scales can actually reduce the impacts of storm surge and reduce flooding from that."

North Carolina has about 220,000 acres of salt marshes, but the protections they offer are dependent on their health and preservation. Coastal development, pollution and climate change all pose threats to these ecosystems. Deaton said plans are in place to help restore them. The South Atlantic Salt Marsh Initiative aims to save 1 million salt-marsh acres, from North Carolina to Florida.

As hurricane activity is projected to increase in frequency and intensity, the role of salt marshes in protecting coastal communities becomes even more critical. Deaton said the evidence is clear that restoring these landscapes is urgent if we want to keep them.

"And if we start to lose our salt marshes," he said, "we're going to start to lose our nursery areas, and that's going to have negative impacts on our fish stocks and our fishing communities that depend on them, not to mention the direct community resilience benefits of preventing erosion and reducing storm surge."

At the state level, North Carolina also has a Salt Marsh Action plan to enhance and rejuvenate salt marshes. Deaton emphasized the importance of coupling these efforts with others that reduce pollution to safeguard coastal communities.

Support for this reporting was provided by The Pew Charitable Trusts.


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Summer temperatures are one more reason for concern by environmental groups about the nuclear waste stored along the Great Lakes.

There are three nuclear power plants in Michigan and 23 in the Great Lakes watershed. Many of the facilities store their hazardous waste outdoors, in dry-cask storage along the waters in Michigan and Canada. Environmental groups said about 80,000 tons of high-level radioactive waste now rest near the Great Lakes.

Kevin Kamps, radioactive waste specialist for the nonprofit Beyond Nuclear, said proximity to major freshwater sources is just one issue.

"The dangers are, you have to 'radiation field' this stuff constantly, because exposure to a person at close range can deliver a fatal dose of radiation within a matter of minutes," Kamps explained. "You also need to contain it and isolate it from the environment."

The Michigan group Citizens' Resistance at Fermi II is working with other local and national organizations to find solutions. They include promoting renewable energy and demanding authorities such as the Nuclear Regulatory Commission enforce what's known as "hardened" on-site storage, which they believe can more safely secure nuclear waste.

DTE Energy, the operator of Fermi II, responded to the concerns in a statement, saying in part "Fermi's used fuel is stored in hardened canisters, protected per strict federal guidelines and constantly monitored."

Jesse Deer In Water, community organizer for Citizens Resistance at Fermi II, said many people are under the impression there are no radiation leaks from the dry-cask storage fuel ponds but his organization disagrees.

"Because it's still hot fuel inside of it," Deer In Water asserted. "It's still highly unstable and for it to be just completely contained without any venting causes it to, like, build up, like a radioactive gas inside of it that can, like, catch on fire and explode."

DTE Energy also noted the canisters "undergo rigorous testing and analysis to ensure they can safely hold up through natural disasters."