Yes but how does this analysis change if you do include the carbon costs of manufacturing and energy generation / transmission? Would that tip the balance in favor of ICEs?
This kind of lifecycle analysis is suuuuper sensitive to your assumptions and even your values. Like: How is the electricity being generated? Do we assume the grid will continue to evolve away from coal and towards natural gas/renewables? What's your discount rate on the health of people in the future versus now? Do we account for the costs of making solar panels? How do you measure a given amount of particulate air emissions now (with an immediate and semi-quantifiable effect) against a given amount of carbon emissions (with a longer-term and more uncertain and harder-to-quantify effect). Do you account for the impact of these on economic growth? On the trajectory of technological progress, which might impact future carbon and/or particle emissions? It's a total nightmare!
I feel that this is all too complicated for us to sit around and figure out with spreadsheets and it would make more sense to just put long-term taxes on all the externalities and let markets sort things out as well as they can. But that seems to be politically off the table...
Agree that's it's difficult to model, but given the massive public policy implications, still seems important to do, no? Like we could input the low end and high end of reasonable assumptions and come up with a sensitivity analysis for a range of outcomes. E.g. if the spread of outcomes are that EVs are 50x better than ICEs on the high-end vs ICEs are 2x better on the low-end, that asymmetrical spread of outcomes would support a diff set of policies than the reverse.
The more interesting conspiracy theory is that de-carbonization efforts in 1st world countries (EVs, solar panels, etc.) are just a shell accounting game of moving carbon costs geographically to 3rd world countries and up the supply chain to mining, manufacturing, and energy transmission. And the friction costs of this shell game actually result in even a higher magnitude of emissions to everyone's detriment.
Of, for sure it's important. I think I was just trying to comfort myself for not being able to answer your question.
Do you have a reference for your more interesting conspiracy theory? (I'm interested in it, but it's always much easier to evaluate someone else's model than to build your own.)
In my mind, there are 2 related but distinct ideas:
1. Offshoring - decarbonization projects in 1st world countries require even worse carbon damage in 3rd world companies. E.g. the rare earth metals for EV batteries, solar panels, etc. come from open-air environmentally-disastrous mining pits in China
2. Supply Chain - even within a country, decarbonization projects move carbon costs up the supply chain to obfuscate greater carbon costs. E.g. Generating, storing, transmitting electricity for EVs is worse than the existing extraction, refinement, distribution chain for ICEs
I find myself thinking that if we have been ignoring brake and tire particulates, and they are significantly more than emissions from the engine, well... maybe we should be ignoring the engine emissions too.
It seems like the argument is: "In general, electric cars produce *way* less pollution. But, if you look at this one specific type of pollution that nobody really thinks about or cares about, they actually produce *more* pollution! Therefore: electric cars are bad!"
I don't disagree with the actual text of your article, but you seem to have completely ignored the question of whether this matters. And then your article title "Conspiracy theory: Electric cars make more air pollution than gas cars" seems to be designed to be read in a way that is both false and harmful.
Ah yes—resuspension is definitely significant! But there's a bunch of subtleties about that which I wasn't able to resolve.
1. Papers seem to agree that resuspension increases linearly-ish just like tires and brakes.
2. And they agree that resuspension is a major factor, although with widely varying estimates, due to the fact that it's very hard to figure out from, e.g., a chemical analysis if a particle has been on the ground before.
3. Since resuspension increases with weight and EVS are heavier that could work against EVs in the total emissions calculation.
4. But resuspension is very different than other emissions because of the "re". You need to consider the amount of material available to be suspended. This depends on the situation (and maybe the other sources of emissions)
5. You also also need to consider that if tiny particles are created they will float in the air a long time and probably land far away somewhere not on a road. So it shouldn't be possible for the same mass to be resuspended over and over again indefinitely as small particles.
There's one mental model in which there's a given amount of "stuff to get resuspended" and so having a heavier car will just lead to it getting resuspended *sooner* and floating away from a road, but won't have much impact on steady-state levels. There's another mental model where there's an infinite reservoir of particles to get suspended (e.g. a dirt road) in which case heavier cars would suspend much more. I'm unsure of which of these is correct.
Cool and interesting analysis on the comparison of particulates... Surely, this is completely swamped by larger sources of particulate pollution like forest fires, etc? I guess I thought the kind of "emissions" folks cared about for motor vehicles were the climate-impacting kinds - the particulate emissions seem like a red herring, no?
> Surely, this is completely swamped by larger sources of particulate pollution like forest fires, etc?
That's an interesting question! At four sites in California, Jung et al. (https://ww2.arb.ca.gov/sites/default/files/2022-06/18RD017%20-%20Final%20Report.pdf) attributed 9-16% of PM2.5 to brakes and 6-13% to tires, as compared to 2-7% for gasoline engines and 4-15% for diesel engines. Let's call that a total of 37%. The average total PM2.5 was apparently around 12 μg/m³, so we might estimate that vehicles altogether are adding around 4.5μg/m³ to the air. They don't mention fires anywhere in their article, so I guess they weren't around at the time.
Meanwhile, how much do forest fires add? That's a bit tricky because it's very local, people are often indoors (or have air purifiers) to reduce exposure, etc. A VERY rough estimate would be to look at this picture of overall levels over time (https://dynomight.net/air/#particles-outdoors) where it seems like the fires nearby LA in September 2020 raised levels from "moderate" (12-35.4) to "unhealthy" (55.5-150.4) and seemed to last for 1/3 of a month. If we take the average of those two bands, that's a delta of (150.4+55.5)/2 - (35.4+12)/2 = 79.25. And if we amortize that 1/3 of a month over a full year that equates to an average of 79.25 * (1/3) * (1/2) = 13.2.
So if you assume fires like that happen every year and people make no extra action to avoid exposure at the time... possibly?
I suppose the best argument in favor of electric and/or hybrid cars, is the fact that electric power can be generated from renewable sources almost everywhere.
A whole country might be dependent on a a few nuclear/coal/gas plants, which might also import fuel from a fewer extraction points in the world.
However each district or even small town can have a small renewable power plant based on either solar, wind, water, or whatever works best. Even a single house could be almost entirely independent in electric power nowdays!
Of course infrastructure and batteries are still huge problems to solve, but I would rather have huge wind turbines near me than the coal plant that causes cancer to a large part of the population..
So my personal conspiracy theory, is that any pushback to the electrification of cars, starts from the centers of power that do not want to loose their grip on resources/power, against distributed renewable energy. It's a bigger fight against the distribution of power, and cars are a small part of it.
Tire emissions may not all be airborne, but they do end up in the environment, eventually being washed into rivers and ending up in the ocean.
Electric cars also have higher acceleration which contributes significantly to tire wear.
There is no compelling reason to abandon gas cars because of local pollution. Today's cars are not major emitters, except for CO2 which is not pollution, but may be a contributor to global warming.
Yes but how does this analysis change if you do include the carbon costs of manufacturing and energy generation / transmission? Would that tip the balance in favor of ICEs?
This kind of lifecycle analysis is suuuuper sensitive to your assumptions and even your values. Like: How is the electricity being generated? Do we assume the grid will continue to evolve away from coal and towards natural gas/renewables? What's your discount rate on the health of people in the future versus now? Do we account for the costs of making solar panels? How do you measure a given amount of particulate air emissions now (with an immediate and semi-quantifiable effect) against a given amount of carbon emissions (with a longer-term and more uncertain and harder-to-quantify effect). Do you account for the impact of these on economic growth? On the trajectory of technological progress, which might impact future carbon and/or particle emissions? It's a total nightmare!
I feel that this is all too complicated for us to sit around and figure out with spreadsheets and it would make more sense to just put long-term taxes on all the externalities and let markets sort things out as well as they can. But that seems to be politically off the table...
Agree that's it's difficult to model, but given the massive public policy implications, still seems important to do, no? Like we could input the low end and high end of reasonable assumptions and come up with a sensitivity analysis for a range of outcomes. E.g. if the spread of outcomes are that EVs are 50x better than ICEs on the high-end vs ICEs are 2x better on the low-end, that asymmetrical spread of outcomes would support a diff set of policies than the reverse.
The more interesting conspiracy theory is that de-carbonization efforts in 1st world countries (EVs, solar panels, etc.) are just a shell accounting game of moving carbon costs geographically to 3rd world countries and up the supply chain to mining, manufacturing, and energy transmission. And the friction costs of this shell game actually result in even a higher magnitude of emissions to everyone's detriment.
Of, for sure it's important. I think I was just trying to comfort myself for not being able to answer your question.
Do you have a reference for your more interesting conspiracy theory? (I'm interested in it, but it's always much easier to evaluate someone else's model than to build your own.)
Candidly have not looked into this personally, but here are some claims just from googling:
https://www.vox.com/energy-and-environment/2017/4/18/15331040/emissions-outsourcing-carbon-leakage
https://www.theguardian.com/environment/2014/jan/19/co2-emissions-outsourced-rich-nations-rising-economies
https://www.nytimes.com/2018/09/04/climate/outsourcing-carbon-emissions.html
In my mind, there are 2 related but distinct ideas:
1. Offshoring - decarbonization projects in 1st world countries require even worse carbon damage in 3rd world companies. E.g. the rare earth metals for EV batteries, solar panels, etc. come from open-air environmentally-disastrous mining pits in China
2. Supply Chain - even within a country, decarbonization projects move carbon costs up the supply chain to obfuscate greater carbon costs. E.g. Generating, storing, transmitting electricity for EVs is worse than the existing extraction, refinement, distribution chain for ICEs
I find myself thinking that if we have been ignoring brake and tire particulates, and they are significantly more than emissions from the engine, well... maybe we should be ignoring the engine emissions too.
Great breakdown, much appreciated!
Wow, this is a lot of work for a pretty esoteric topic. Thank you!
Don't thank me—thank my hideously poor skill at estimating how much effort things will take despite ceaseless evidence to the contrary!
It seems like the argument is: "In general, electric cars produce *way* less pollution. But, if you look at this one specific type of pollution that nobody really thinks about or cares about, they actually produce *more* pollution! Therefore: electric cars are bad!"
I don't disagree with the actual text of your article, but you seem to have completely ignored the question of whether this matters. And then your article title "Conspiracy theory: Electric cars make more air pollution than gas cars" seems to be designed to be read in a way that is both false and harmful.
I like how you think. We can certainly optimize tire emissions if we tried to do so, I mean we are just now getting prototypes for airless tires.
Fun article, thanks! You mention dust up top but don't include it in your analysis. This paper finds that resuspended dust is the largest source of PM2.5 emissions for cars: https://www.sciencedirect.com/science/article/abs/pii/S0048969720379717
Any thoughts on that paper or the EV implications for dust?
Ah yes—resuspension is definitely significant! But there's a bunch of subtleties about that which I wasn't able to resolve.
1. Papers seem to agree that resuspension increases linearly-ish just like tires and brakes.
2. And they agree that resuspension is a major factor, although with widely varying estimates, due to the fact that it's very hard to figure out from, e.g., a chemical analysis if a particle has been on the ground before.
3. Since resuspension increases with weight and EVS are heavier that could work against EVs in the total emissions calculation.
4. But resuspension is very different than other emissions because of the "re". You need to consider the amount of material available to be suspended. This depends on the situation (and maybe the other sources of emissions)
5. You also also need to consider that if tiny particles are created they will float in the air a long time and probably land far away somewhere not on a road. So it shouldn't be possible for the same mass to be resuspended over and over again indefinitely as small particles.
There's one mental model in which there's a given amount of "stuff to get resuspended" and so having a heavier car will just lead to it getting resuspended *sooner* and floating away from a road, but won't have much impact on steady-state levels. There's another mental model where there's an infinite reservoir of particles to get suspended (e.g. a dirt road) in which case heavier cars would suspend much more. I'm unsure of which of these is correct.
Cool and interesting analysis on the comparison of particulates... Surely, this is completely swamped by larger sources of particulate pollution like forest fires, etc? I guess I thought the kind of "emissions" folks cared about for motor vehicles were the climate-impacting kinds - the particulate emissions seem like a red herring, no?
> Surely, this is completely swamped by larger sources of particulate pollution like forest fires, etc?
That's an interesting question! At four sites in California, Jung et al. (https://ww2.arb.ca.gov/sites/default/files/2022-06/18RD017%20-%20Final%20Report.pdf) attributed 9-16% of PM2.5 to brakes and 6-13% to tires, as compared to 2-7% for gasoline engines and 4-15% for diesel engines. Let's call that a total of 37%. The average total PM2.5 was apparently around 12 μg/m³, so we might estimate that vehicles altogether are adding around 4.5μg/m³ to the air. They don't mention fires anywhere in their article, so I guess they weren't around at the time.
Meanwhile, how much do forest fires add? That's a bit tricky because it's very local, people are often indoors (or have air purifiers) to reduce exposure, etc. A VERY rough estimate would be to look at this picture of overall levels over time (https://dynomight.net/air/#particles-outdoors) where it seems like the fires nearby LA in September 2020 raised levels from "moderate" (12-35.4) to "unhealthy" (55.5-150.4) and seemed to last for 1/3 of a month. If we take the average of those two bands, that's a delta of (150.4+55.5)/2 - (35.4+12)/2 = 79.25. And if we amortize that 1/3 of a month over a full year that equates to an average of 79.25 * (1/3) * (1/2) = 13.2.
So if you assume fires like that happen every year and people make no extra action to avoid exposure at the time... possibly?
Great analysis!
I suppose the best argument in favor of electric and/or hybrid cars, is the fact that electric power can be generated from renewable sources almost everywhere.
A whole country might be dependent on a a few nuclear/coal/gas plants, which might also import fuel from a fewer extraction points in the world.
However each district or even small town can have a small renewable power plant based on either solar, wind, water, or whatever works best. Even a single house could be almost entirely independent in electric power nowdays!
Of course infrastructure and batteries are still huge problems to solve, but I would rather have huge wind turbines near me than the coal plant that causes cancer to a large part of the population..
So my personal conspiracy theory, is that any pushback to the electrification of cars, starts from the centers of power that do not want to loose their grip on resources/power, against distributed renewable energy. It's a bigger fight against the distribution of power, and cars are a small part of it.
Tire emissions may not all be airborne, but they do end up in the environment, eventually being washed into rivers and ending up in the ocean.
Electric cars also have higher acceleration which contributes significantly to tire wear.
There is no compelling reason to abandon gas cars because of local pollution. Today's cars are not major emitters, except for CO2 which is not pollution, but may be a contributor to global warming.