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Extreme heat a ‘silent killer’ in poorest Vancouver areas

A new UBC study suggests link between economic vulnerability and heat wave deaths — predicted to worsen with climate change.

Lower Mainland neighbourhoods that become “urban heat islands” thanks to fewer trees and more pavement can also see more deadly heat waves when combined with unemployment or older populations, according to a new study.

Environmental Health Perspectives journal

Lower Mainland neighbourhoods that become “urban heat islands” thanks to fewer trees and more pavement can also see more deadly heat waves when combined with unemployment or older populations, according to a new study.

Be careful wishing for more sizzling summers. For Vancouver’s poor and unemployed, soaring temperatures that come with climate change could be deadly.

A new study suggests that more economically vulnerable neighbourhoods in Metro Vancouver have the highest death rates during extreme heat waves.

And according to B.C. Centre for Disease Control scientist Sarah Henderson, who co-authored the study in Environmental Health Perspectives journal, the findings could help protect people from more frequent extreme heat — such as by planting more trees in heat-absorbing highly paved areas, and educating residents about drinking more water during heat waves.

“Heat is a silent killer,” explained Henderson, an assistant professor at the University of British Columbia’s School of Population and Public Health, in a phone interview. “You don’t see it, but from a public health perspective it has a really big impact.”

The study used an index of economic vulnerability developed with the region’s chief medical officers — the Vancouver Area Neighborhood Deprivation Index (VANDIX) — and mapped it over the hottest-temperature areas, known as “urban heat islands,” from 1998 to 2014.

In the hottest year overall, 2009, a weeklong heat wave where the humidex approached 35C coincided with 110 deaths above the normal.

“If those people would have died of H1N1,” she added, “it would have been on the news.”

The worse-off neighbourhoods for heat deaths the study found, tended to be those with less green space or tree cover — and ones higher unemployment or more retirees. The Downtown Eastside was particularly high, but also parts of New Westminster, Surrey and Abbotsford.

“Possibly what’s happening is those people are home all day during really hot weather; they’re not getting out to air conditioned environments or shade in the streets,” Henderson said.

“Generally, there’s a lot of concrete or asphalt material that absorbs energy from the sun over course of the day, and not a lot of trees or greenness to provide shade.”

Additionally, trees have a bit of moisture and that also makes the area around them cooler, she said.

Henderson warned that, as the world’s climate changes, scientists predict the problem will likely worsen.

“They’ll be hotter, last longer and be more frequent,” she said. “We hope to help prepare the population for decades to come, so we don’t have 110 excess deaths over seven days again.”

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