Efforts to improve indoor air quality have taken on fresh urgency as more cities experience intense pollution from climate-change-fueled wildfires.
Article Source: Bloomberg
Photo Credit: Jamie Kelter Davis / Bloomberg
At the Urban Green Building conference in New York City last week, real estate professionals and experts on sustainable building kibbitzed and confabbed about how to create a more climate-friendly built environment. While the planned topics included electrification and green retrofits, the subject nobody could escape was outside the windows of the NYU Kimmel Center.
“As you’re looking through orange air, questioning ‘am I on Mars or Manhattan?,’ it becomes clear that the best place for refuge becomes our buildings,” said John Mandyck, the chief executive officer of the Urban Green Council. “Buildings are a critical element for climate resiliency.”
The still-burning wildfires that recently shrouded much of the Northeast and Central US in dense smoke underscored the realities of climate change for a part of the US that had largely avoided such air quality emergencies in recent decades, as millions of residents of this heavily urbanized region were urged to stay inside homes and offices to avoid soaring pollution levels.
The fires, fueled by drought and high temperatures across Canada, also provided a stark new illustration of the importance of indoor air quality — an issue that rose to prominence during the Covid pandemic amid new research on the poor quality of many indoor environments.
“The problem has been that the standards of how we construct and maintain buildings haven’t focused on the health of the people in the buildings, as crazy as it sounds,” said Joseph Allen, director of the Healthy Buildings program at Harvard University’s T. H. Chan School of Public Health, who has been leading the charge on improving indoor air quality, and the health impacts of not doing so. “Those in older buildings are absolutely having bad health impacts.”
In extreme wildfire events, outdoor air quality can hit 400 micrograms per cubic meter of PM2.5 — the fine, invasive particles that can enter the lungs and bloodstream, with serious impacts on human health. Older US homes can have a 50% infiltration factor, due to poorly sealed windows and drafty exteriors, Allen said, so that indoor occupants might still be breathing roughly 200 micrograms per cubic meter of this pollutant, levels associated with increased risks of heart attacks, strokes, and emergency room visits.
Meanwhile, the boardroom of a modern office building equipped with sophisticated air filtration may barely hit a level of 10.
This unprecedented wildfire event — Allen said colleagues in his field were “absolutely stunned” to see New York City achieve the worst air pollution levels in the world — comes as indoor air quality has become a broader area of public health and policy concern. In addition to the recent culture war battle over the documented dangers of gas stoves, a pair of new air quality standards represent milestones in the movement for healthier buildings. The Centers for Disease Control issued a new health-based standard for indoor clean air, while the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) released a new standard for emergency air quality events.
Allen hopes these new standards can help launch a larger movement to invest in new ventilation and air quality technology, such as air purifiers and MERV 13 filters (a measure of the filter’s ability to catch small particles), which he argues are a societal investment in resilience.
“Wildfire smoke, extreme heat, Covid-19 — these same healthy building strategies protect us from all of them,” he said.
Building a Breathable Refuge
Such investments are already in progress, especially in cities of western North America that have seen a growing number of air quality emergencies due to wildfires in recent years.
The effectiveness of some of these interventions has been questioned, such as the well-publicized purchase of less-than-ideal air filters by New York City public schools in 2020, as well as the original Molekule air purifier, which was found to be lacking by testers.
But in general, up-to-date building ventilation tech tends to perform well at filtering wildfire smoke. Scott Frank, an engineer at JB&B, a top NYC building engineering firm, took measurements in the firm’s Lower Manhattan office — which is outfitted with MERV 15 filters — during the height of the wildfire smoke last week. He found 100 times less small particle pollution inside than outdoors.
Updated modern building filtration systems were built to handle these kinds of air pollution events, he said, especially as long as the facades are relatively tight; it just shortens the working life of the air filters. He argues that standards like what ASHRAE released, as well as better federal regulations and requirements around air filtration equipment, can help incentivize air quality upgrades.
The WELL Building Standard, a holistic approach to building health that includes a focus on air quality, has become more widely adopted by new real estate in recent years, with 500-plus locations in New York City and 16,000 buildings nationwide getting WELL Certified. International WELL Building Institute chief product officer Jessica Cooper said that most of the buildings that have utilized the standard are commercial office buildings, and they tend to see a rent premium due to the health benefits of the certification.
The real challenge is introducing air quality improvements to older structures and residential buildings, especially those in lower-income and disinvested neighborhoods. WELL has just finished a pilot to help determine standards for residential buildings, for instance, and plans to expand more into this building sector. The need to better protect where people live underscores the importance of cities focusing on resilience, early warning systems for citizens, and investing in healthier buildings for everyone.
Allen was particularly discouraged about how school systems performed during the wildfire smoke emergency, with some public schools going remote in New York and New Jersey. School districts were given significant federal funding, $122 billion, to invest in better ventilation and filtering technology via the American Rescue Plan, but much of the money remains unspent. With many school buildings having issues coping with extreme heat — and even having to close during hotter months — this kind of investment is imperative.
“If that money had been spent on schools, they could have been places of refuge,” he said. “They should have been. The solution set is so obvious.”
For New York City, older residential buildings often lack central air conditioning, with many only utilizing boilers and steam heat, and therefore relying on window units that are far less effective at filtering outdoor air. Home air purifiers and jury-rigged air filtration systems can help, but ultimately, buildings and homes should be designed and retrofitted to have more airtight facades and modern HVAC systems. (Like traditional central AC equipment, ductless heat pump technology, which provides both heating and air conditioning, will also filter smoky outdoor air.)
Beyond the risks from PM2.5 exposure, urban residents also face an additional risk from wildfire smoke: elevated amounts of harmful ground-level ozone, which can be created as the sooty plumes chemically react with urban pollution from vehicle emissions and other sources.
Mandyck sees building electrification, ideally leading to low-cost and fossil-fuel-free cooling, as a benefit to sustainability and equity as the effect of climate change becomes more extreme. The Los Angeles city council just mandated air conditioning in all rental units, to help mitigate the risk of extreme heat.
“The more that we electrify, the more that we deal with extreme heat for temperature reasons, we’re going to have the benefit of also managing inequality issues,” he added.
Designing for Air Quality Equity
Better awareness of the risks of wildfire smoke can change the way new buildings will be designed. John Rozeluk, an associate principal at Buro Happold Engineering in Los Angeles, says that many buildings in cooler parts of coastal LA and the Bay Area traditionally have not been equipped with air conditioning. But now that wildfire days take up an increasingly large part of the year, that feature will be increasingly necessary, regardless of temperatures.
“As building designers, we need to assess the climate condition and also assess other risks,” Rozeluk said. “That resilience piece will change the way we design things.”
Going forward, Rozeluk suggests buildings need to be designed to take advantage of cooling during clean air days, but during wildfire events, filtration and HVAC systems can turn to economizer mode, reducing ventilation down to the minimum to increase filtration. Air quality threats could also play a larger role in adaptive reuse practices. While preserving older buildings cuts down on embodied carbon, their leaky exteriors need to be improved with pollution and particulates in mind, which means better-sealed facades and replacing older single-pane windows with more modern models. Interiors can be pressurized to avoid infiltration of pollution.
The super-efficient Passive House building standard, which is utilized by many of the most sustainable new buildings, also provides excellent filtration and indoor fresh air. While most often seen in high-end private homes, it can also be employed in affordable housing projects like Sendero Verde, a 709-unit high-rise in Harlem now under construction. Laura Spencer Humphrey, director of sustainability at L+M, the firm behind the building, said it’s important to raise awareness of these buildings and these technologies, to get more such affordable housing built, and to make it easier to finance future projects.
“Equity and access to clean air aren’t just based on wildfires, but housing around freeways and housing in industrial areas,” said Rozeluk. “Those who live in older homes or public housing, or homes that haven’t been fitted with proper ventilation systems, that’s where there’s a disadvantage.”
In an era of increased wildfire smoke, radical new technology isn’t needed to make homes and offices safe, said Mandyck — current best practices can do the job. But this push to improve indoor air quality needs to be part of a broader campaign to decarbonize the building sector, to avoid worsening the conditions that make future fires more likely and more devastating.
“The healthy building movement will be a complete failure if it’s only in a handful of buildings,” Allen said. “We have to make this the norm. It needs to be in our standards and codes.”