Ultrafine particles are killing us, and they are being grossly undercounted (If they are counted at all)
It turns out that we may have been measuring them all wrong.
I have written previously about ultrafine particles, quoting Scott Weichenthal, an Associate Professor in McGill’s Department of Epidemiology, Biostatistics, and Occupational Health:
“Ultrafine particles are incredibly small, allowing them to penetrate deep into the lungs and enter the bloodstream. Increasing evidence suggests these pollutants may contribute to heart and lung diseases, as well as certain forms of cancer."
The biggest source of UFPs is from burning gasoline and diesel in cars and trucks.
Now, a new paper, Air quality standards and WHO’s guidance on particulate matter measuring 2.5 μm (PM2.5) questions whether we are measuring them properly. UFPs are usually included in counts of PM2.5, and the number is expressed as weight, in micrograms per cubic meter. However, the mass of UPFs at PM0.1 is negligible compared to the larger PM2.5 particles; you could have millions of them and not even know, and the number matters more than the mass. The study authors write:
“Evidence suggests that short-term exposure to ultrafine particles is associated with respiratory symptoms and systemic inflammation, and can affect heart rate and blood pressure. Furthermore, long-term exposure to ultrafine particles is associated with increased mortality, especially cardiovascular and lung-related mortality, and several types of morbidity, such as ischaemic heart disease. As the health effects of ultrafine particles are better associated with their number density rather than mass, monitoring and analyzing the number density of particles smaller than either 2.5 μm or 100 nm, in addition to PM2.5, is required to measure the human exposure to and harm from ultrafine particles.”
Simon Jones of Air Quality Matters calls the mass-based metric “fundamentally flawed.”
“It simply weighs the dust. It completely fails to consider the physicochemical characteristics of airborne particles—their specific size, chemical composition, bioavailability of potentially harmful elements, and critically, the particle number concentrations of different-sized particles, including ultrafine particles.”
Almost nobody is measuring UFPs or counting them separately; they are just lumped into the PM2.5 category. Devices for measuring UFPs are costly. And most importantly, UFPs are not regulated.
So, Ontario Premier Doug Ford can fly five times as many passengers through Billy Bishop Airport and not even consider how dangerous this is for all the people living next to the airport or under the flight path. Lord Kelvin wrote, “If you cannot measure it, you cannot improve it,” and with UFPs, we are not even trying.
I thought about UFPs while reading Bruce Lanphear’s recent post in his substack “Plagues, Pollution and Poverty.”
He describes how coronary heart disease was blamed mostly on personal behaviour, but it turned out that lead from car exhaust was a major factor. When lead was removed from gasoline, hypertension and heart disease rates fell significantly. He explains how we missed it:
How do you overlook a leading cause of death for more than a century?
Part of the answer lies in how we think about disease. We focus on what we can measure easily in individuals—cholesterol, blood pressure, behaviors. These are visible, actionable, and clinically useful.
Environmental exposures are different. They are diffuse, shared, and often operate at low levels across entire populations. Their effects are subtle in individuals but substantial in aggregate. They are harder to see—and easier to ignore.
I wrote in my first post about ultrafine particles: “Who knows how many healthy years have been lost or how many billions of medical costs have been incurred because of them, all because we love burning stuff.”
We don’t think much about particulate pollution and completely ignore ultrafine particles because it would be too inconvenient to have to stop burning stuff, particularly gasoline. We don’t test for them or regulate them because we don’t want to know. We go to the doctor with our heart problems and COPD and don’t think about environmental exposures. But I suspect UFPs are like Bruce Lanphear’s lead- killing us, while hidden in plain sight.
While writing this post, I discovered a comment to an earlier one (longer than the post!) by Lyn Folkes complaining about Ontario Premier Doug Ford. It’s worth a read.
It’s the things that you don’t know you don’t know that get you.
In Cradle to Cradle, Bill McDonough and Michael Braungart discuss the problem of monstrous hybrids that slowly degrade, abrade, and put out small particulates, perhaps some of the ultrafine particles you mention. Our polyester clothing is one example. Tire wear is another. There are many. Most of them involve products unknown to nature that we spread around on the earth's surface. How do you stop using them if they are cheaper, stronger, and more durable than natural products like sisal, cotton, hemp, ramie, and bark tanned leather? I wrote about this myself here: https://wayneteel513055.substack.com/p/are-synthetic-fibers-killing-us
I have no solution other than switching products if you can, but the way we produce cotton (as an example) is not sustainable either. When a problem is embedded in a dominant system it is extremely difficult to change, especially when the corporations adamantly oppose change. "Mutual coercion, mutually agreed upon" is not an easy fix when the solutions offered are inadequate to the scale of the problem.