“Out of the frying pan and into the fire.” That is how Portlanders might describe the nearly incessant stretch of above-average temperatures we've faced in recent years.
As summers have been historically mild in the Pacific Northwest, shifting to warmer weather for longer periods could put the Rose City and its residents under considerable stress. High temperatures, particularly in areas referred to as “urban heat islands,” pose serious health risks. The danger is compounded by the increased presence of respiratory irritants like smog and ozone that form when heat alters the chemistry of emissions from motor vehicles and industrial operations.
On days of extremely high temperatures, in neighborhoods where the heat island effect and poor air quality intersect, the health of vulnerable populations—older adults and very young children, the unhoused and those without access to services, residents with cardiovascular and respiratory diseases—is in jeopardy. That means Portland, and cities like it all over the world, are facing the potential of a climate-change-induced public health crisis.
Into the fire indeed.
The likelihood of such a crisis, however, can be greatly reduced. The City of Portland, being on the leading edge of action to reduce carbon emissions and prepare for the effects of climate change, has a plan to transform the Rose City into one of the most climate-resilient cities in the world.
Portland’s Climate Action Plan calls for reducing the heat island effect, minimizing health issues related to degraded air quality, and using data-driven, up-to-date maps “to help inform decisions and priorities about projects and programs that help cool the urban environment.”
To complete these actions, the city enlisted the expertise of PSU researchers with expert knowledge of disciplines related to sustainability science. Dr. Shandas leads the team, which is working with the city, state, NGOs, and community groups to assess human vulnerability to heat stress and air degradation within the city.
“To prepare for the possible negative health impacts of extreme heat and air pollution, we have to know where heat islands are, and air pollution is concentrated,” said Dr. Shandas, Associate Professor of urban studies and planning. “We also need to know where our vulnerable residents are. Then, when we layer all that data on a map, we can see where we need to direct our efforts.”
During the project's first phase, the research team organized workshops that identified several characteristics of vulnerability to heat stress and poor air quality. Those included age, income, health, homes without air-conditioning, and access to city services. The team analyzed city demographic data using those conditions to reveal at-risk populations.
PSU Geospatial Research Analyst Jackson Voelkel combined the population data with the city’s tree canopy cover, street-level traffic-related air quality records, and high-resolution, GPS-located temperature measurements. Layered over a map of Portland, the data identified, in vivid color, areas where the city and its partners need to concentrate efforts to mitigate the heat island effect, improve air quality, and protect public health.
“An advantage of using maps to present complex issues like managing heat islands in urban settings is that you can communicate huge, complicated data sets in a very accessible way,” said Voelkel. “Maps can help people visualize the unseen world around them. Anyone can see trash on the street. You don’t necessarily see air pollution. A map like this changes that.”
The map, part of an online, interactive toolkit Shandas is creating, will soon be available for public use. When it comes online, users can explore Portland like never before: peering into its hotspots and polluted zones and comparing their neighborhoods to others while exploring the relationships between tree cover, heat, pollution, and public health.
“We hope this map will get people asking questions,” Shandas said. “‘Is my neighborhood an urban heat island?’ ‘What can I do to cool the neighborhood down?’ ‘Is the air quality in this park healthy enough for a child with asthma to play in?’ ‘Should the neighborhood establish a plan of action to keep vulnerable residents safe during heatwaves?’”
With trouble zones in plain sight, city and community stakeholders can act to reduce the heat island effect and improve air quality throughout the city with a focus on the city's hotspots.
“We need to start preparing for the effects of climate change,” said Shandas. “Which means we need to start a conversation about how people, particularly those in cities, will be exposed to extreme heat, degraded air quality, fires, floods, landslides, and other events.”
That conversation has begun. Researchers at PSU are helping the community identify vulnerable neighborhoods and populations. The city is putting its climate initiatives on the map. And while improving Portland’s climate resiliency may not exclude us from longer, hotter summers in the future, it will no doubt improve how we protect the health of our most vulnerable residents.