Pandemic Lesson #3: We Need an Air-Quality Revolution
The third of five lingering thoughts that I'm taking away from the pandemic: a simple solution that will profoundly change society for the better is right in front of our noses.
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In the summer of 2015, I moved to Los Angeles. My first apartment was at the western end of the San Fernando valley (“The Valley” in both LA and pop-culture lingo) about 10 miles south of Aliso Canyon.
Now, if you’re like I was in 2015, you’ve never heard of Aliso Canyon. And I would probably still be ignorant of the place if it weren’t for the fact that, in fall 2015, Aliso Canyon was home to the worst natural gas leak in U.S. history.
Many residents became sick, thousands of families were relocated, and numerous mitigation measures were established for the protection and health of the local community. Of note, SoCal Gas (the owner of the leaking well) purchased portable air filtration units for every classroom, office, and common area in all schools within five miles of the leak. A total of 1,756 plug-in air filters were delivered to eighteen schools.
Of course, this set up a natural experiment that allowed researchers to compare the schools within the 5-mile radius with air filters to schools just outside that area that didn’t receive the devices.
That study, “Air Filters, Pollution, and Student Achievement” found that installing air filters raised test scores in mathematics and English by 0.20σ (below). To put that in context, a 1999 study found that cutting class size by one third led to a 0.22σ improvement in academic performance.
However, cutting class sizes by a third requires a huge monetary investment in additional teachers and schools while the air filters cost only ~$1,000 per year per classroom. This means that with a 0.2σ increase in test scores per $1,000 of expenditure, "air filter installation is one of the most cost-effective education policies available to policymakers today."
This isn’t the only study that finds improving air quality leads to significant improvement in student performance. Study after study after study link increased air quality with increased student performance. The EPA’s “Research References Related to Indoor Air Quality in Schools” page contains 83 studies.
And air pollution affects more than just students. Chess players and baseball umpires make more mistakes when air pollution is higher. Airline pilots are worse at performing maneuvers in a flight simulator when cockpit CO2 levels are higher. Fruit packers become less productive and the quality of politicians’ speeches goes down when fine particulate matter (PM2.5) increases. Multiple studies have found that office workers have lower cognitive scores and perform worse when exposed to higher PM2.5 and lower ventilation rates. A 2019 OECD study based on satellite data estimates a 1μg/m3 increase in PM2.5 concentration causes a 0.8% reduction in real GDP. Stock market returns go down when air pollution is high in Manhattan.
Even crop yields are affected by air pollution. While anatomically different, plants have a respiratory system too and a 2022 study found that decreasing nitrogen dioxide pollution to the current fifth percentile level would result in huge increases in global crop yields.
Air quality goes beyond student performance and economic productivity. It is one of the main drivers of human disease and disability.
The World Health Organization estimates that outdoor and indoor air pollution leads to seven million premature deaths every year. The IHME estimates that air pollution results in over 213 million disability-adjusted life years lost (below). A large study of eight European cohorts found that outdoor air pollution “is associated with mortality even at low pollution levels below the current European and North American standards and WHO guideline values.”
When we breathe air pollution into our lungs, some of it is absorbed into the blood stream, allowing it to travel to and potentially impact every organ system in the body. From strokes and cardiovascular disease and brain cancer and autoimmune diseases, to lung cancer and COPD and cognitive decline and Alzheimer’s and Parkinson’s disease, research has linked air pollution to just about every major human disease. Even if you’ve never smoked tobacco, research finds increased rates of lung cancer from air pollution.
These health effects start even before birth. In communities surrounding areas where EZ Pass was introduced (reducing PM2.5 because cars pass through rather than idling at tolls), rates of pre-mature birth premature births fell by between 6.7-9.2% and the incidence of low birth weight fell by between 8.5-11.3%. Additional studies find similar conclusions.
Obviously, SARS-CoV-2/COVID-19 brought air quality front and center. So far, I’ve purposed ignored respiratory pathogens because I want to convince you that an air quality revolution would go far beyond controlling ‘cold & flus.’
But yes, improving air quality would reduce the burden of SARS-CoV-2, influenza, RSV, and every other pathogen that spreads via the air. This is why the first three points in my long-term COVID control plan from my January 4th 2022 newsletter were:
Investment by local, state, and federal governments to increase ventilation and sanitization of indoor air in all public buildings.
Direct investment or tax credit/rebate for individual households to increase ventilation and sanitization of indoor air in private residences.
Updating and setting modern air quality standards, both indoor and outdoor.
Even in hospitals, testing consistently finds measurable levels of multiple infectious bacteria, viruses, and fungi. Installing portable air filters eliminates essentially all of them (below). Other studies find similar effects. Here is a review article of over 100 studies of various types and designs about the effect of hospital air quality on patients.
Even outside of the hospital, ambient exposure to air pollution has been linked to subsequent SARS-CoV-2 infection and increased COVID-19 severity. Improving ventilation in classrooms has been shown to reduce transmission of SARS-CoV-2.
Improving air quality would especially work for controlling infectious disease, because rather than requiring active effort by individuals (putting on a masks, etc.), it works passively in the background at the community level. This means it won’t just help control current endemic diseases but it would proactively help control all future outbreaks.
For example, measles spreads via the air and as I mentioned in “Our Immune Systems Weren't Damaged by SARS-CoV-2,” there is currently a measles outbreak in Ohio. Studies suggest that “significant risk reduction [for measles] can be achieved through enhancing building ventilation and filtration systems.”
Recently, there has been a flurry of news that the U.S. Consumer Product Safety Commission is considering regulations around gas stovesbecause they produce nitrogen dioxide while operating. While there is reasonable discussion around the quality of evidence on the impact of gas-stove NO2, what isn't in dispute is that second-hand tobacco smoke, mold, and PM2.5 do have a measurable impact on human health. And improving air quality would reduce those impacts plus any potential impacts from gas stoves or any other damaging sources.
The air quality revolution we need has three focuses:
Ventilation: to lower carbon dioxide levels and noxious gas concentrations
Filtration: to remove fine particulate matter, mold, and smoke
Sanitization: to eliminate airborne pathogens such as viruses and bacteria
The frustrating part is that we currently have all the technology we need to do these three things. This isn’t nuclear fusion or interstellar travel; absolutely nothing needs to be invented. It is simply a matter of will and installation.
For ventilation: HVAC systems can be modified or upgraded to perform >6 ACH (air changes per hour, or how many times a room’s volume of air is replaced every hour). This is the recommendation of The Lancet’s COVID-19 commission.
For filtration: as we’ve already discussed, HEPA and MERV filters are a cost-effective way of filtering the air. But even the low-cost Corsi-Rosenthal boxes have been shown to be effective at air filtration. They are even a great weekend project to build with kids. Here is an overview of air filtration technologies.
For sanitization: far-UVC lamps (a range of ultraviolet light that isn’t damaging to human tissue) have been shown to be highly effective at killing respiratory pathogens. They can be permanently installed near the ceiling or in HVAC systems but they also come in portable versions.
Improving air quality would have profound and widespread effects on human health, productivity, and well-being. It would increase academic and professional performance while reducing the burden of nearly ever major human disease. These effects would compound on each other as health, performance, and well-being all influence one another. Improving air quality is simply one of the most cost-effective public health interventions that we could implement.
Just as previous generations implemented protocols to decrease food-borne and water-borne disease, it is now our generation’s responsibility to do the same with the air. We need an air quality revolution.
“Pandemic Lesson #1: Ashes to Ashes, Dust to Dust,” was about our chronic underinvestment in the physical world.
“Pandemic Lesson #2: The Complexity Ocean,” was about the growing complexity of the modern world.
Each air-filter unit is ~$700 with a five-year lifespan, the filters are $300 and changed annually, each filter requires ~$24/month in electricity, with an estimated 1.5 filters per classroom = ~$1,000
Naturally, because the Commissioner said “everything’s on the table,” this was immediately interpreted as an immediate nationwide ban rather than the numerous other options available.
All good, though $24/month in electricity for 1 to 1.5 air purifiers per classroom is about an order of magnitude higher than it would be to run during occupied hours.