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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One of many federal agencies facing cuts by the Trump administration's Department of Government Efficiency is the National Oceanic and Atmospheric Administration. Scientists said it will threaten Americans' safety, especially in states with extreme weather events, including Montana.

NOAA employees are bracing for expected staffing cuts of up to 20%, or more than 1,000 jobs. Among other roles, NOAA's National Weather Service provides open-source weather data the majority of U.S. forecasters use, including for warnings and advisories.

Bernadette Woods Placky, chief meteorologist and vice president of engagement for Climate Central, said NOAA provides critical weather data.

"Because of NOAA data, we know when to evacuate ahead of storms, fires," Woods Placky explained. "We know when not to evacuate, which is also really critical because that saves a lot of money and a lot of time."

Other conditions NOAA data helps Montanans understand include avalanches, floods, high winds, air quality, red-flag warnings and extreme heat. Woods Placky added beyond short-term predictions, NOAA data helps farmers understand what to plant and when to harvest, especially as crop hardiness zones shift due to climate change.

NOAA's data on storm events and climate change dates back to 1950 and goes beyond U.S. borders. Woods Placky pointed out unstable governments can interrupt data gathering.

"When you get that gap in the data, it invalidates the long-term data sets," Woods Placky stressed. "You can't carry it with the same weight to tease out longer-term trends to keep people safe and prepared on longer-term shifts that we're seeing."

She added global groups use NOAA's data, including the Intergovernmental Panel on Climate Change and the United Nations.

David Dickson, TV engagement coordinator for the nonprofit Covering Climate Now, said while some have argued services NOAA offers could be privatized, the sentiment shows a misunderstanding.

"To argue against NOAA not being useful because we have private companies offering weather apps would be to argue against farmers because we have grocery stores," Dickson emphasized. "It really does fund the invisible backbone of virtually everything we consume."


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Forty religious leaders from different denominations gathered in Texas this week to call for an end to fossil-fuel subsidies and expansion of related infrastructure.The meeting occurred just days before the Environmental Protection Agency announced it is rolling back landmark environmental regulations.

Aly Tharp, Gulf South organizer for GreenFaith USA, said the faith community has a moral obligation to oppose the cuts and organize against the changes.

"So, when we listen to the science and when we listen to Scripture, to moral lessons from all faith traditions,' she said, "it's a clear call that we're on a path that's mutually assured destruction. And we must change and start investing in our common survival. "

The religious leaders took part in public demonstrations outside the annual oil and gas industry CERAWeek conference in Houston. They also drafted a letter to the Trump Administration calling for subsidy money to be redirected to improve the environment.

Faith leaders toured communities near fossil-fuel facilities in the Houston area. Ilka Vega, executive for economic and environmental justice for United Women in Faith, said the neighborhoods are predominantly made up of low-income people of color.

"Seeing through their eyes what used to be their post office, their houses, their schools and everything that was taken away from them," she said. "Places where they would go fishing and where they would go swimming and have fun, that were contaminated."

The head of the EPA has said he and President Donald Trump support rewriting the agency's 2009 finding that planet-warming greenhouse gases endanger public health and welfare.

Religious leaders and people of diverse faiths are being invited to sign the letter to the Trump administration on the GreenFaith USA website.

Virginia has certain restrictions in place for workers handling animal waste in order to avoid contaminating groundwater sources. But one expert says the Commonwealth could do more to educate people about the risk.

Last year, Virginia updated regulations for animal waste at animal feeding operations. One of those regulations included ensuring that storage areas are higher than one foot above the seasonal high water table.

Bryan Dunning, a senior policy analyst for the nonprofit Center for Progressive Reform, said the Commonwealth took a step in the right direction with increased monitoring.

"It's for all facilities constructed after '98," he said. "So, that is some improved monitoring to get an idea of if there are problems with the facility that is breaching into the groundwater."

Dunning added that pre-1998 systems are grandfathered in under the new regulations. The agriculture industry accounts for half of the nitrogen and phosphorus that sucks oxygen out of Chesapeake Bay, which is needed to sustain aquatic life.

Dunning said Virginia officials could take steps to further combat groundwater contamination from manure at animal-feeding operations. That includes making data electronically available to the general public without the need to file a Freedom of Information Act request.

"Public information for these sorts of things is really important because if you source your water for your house from a private well, you're responsible for making sure that your water's clean," he said. "And without having that sort of publicly available database, basically to increase public knowledge, you're kind of operating in an information blackhole. "

Dunning added that unauthorized discharge of animal waste should be publicly disclosed. Confinement operators have said they are always looking for ways to be more environmentally friendly, while also keeping up with consumer demand for high-quality meat.


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