Ah yes let's avoid the real issue of car tyres producing 2000x the particle pollution per distance travelled compared to already insanely filtered exhaust and distract ourselves with tiny improvements that make no difference.
ICE emissions will be irrelevant in 10 years when they're all but banned anyway, and rubber tyres will still be the only way to drive on the road. In fact it'll be way worse with the average EV being heavier and emitting more due to more tyre wear.
So vehicle exhaust is 5% of fine particulate matter in the Bay Area, whereas road dust, tire, and brake emissions are 20%. (Where’s the breakdown between brake dust and tire dust? EVs and even hybrids can substantially reduce brake dust. Heck, an eddy current brake could too, if anyone cared to build one. Might be bad for unsprung weight.)
And commercial cooking is 8%, it I suspect this massively understates the problem, since commercial cooking can easily concentrate its emissions right where large numbers of people are walking around.
But here’s the hilarious commercial cooking regulation:
Read the second paragraph: it applies only to charbroilers and only in restaurants that buy 500 or 1000 lbs of beef per week. That fancy Greek restaurant that smokes up three square blocks of a fancy downtown, but it’s all lamb and fish? No emission controls. That little neighborhood place making tasty bento boxes with pork, and probably less than 500lbs anyway? No emission controls. That portable smoked turkey place at lots of county fairs? (Those are IMO horrible to be around.). No regulation.
And let’s not even mention the single biggest source: residential wood combustion at 12%. It’s politically hard to address, but residential wood combustion serves almost no economic purpose and could come very close to stopping without harming people or the economy. Almost everyone already has a perfectly fine non-wood-fired heater, and a narrow exception would be fine.
And yet BAAQMD is willing to ban the sales of gas fired water heaters in a few years, never mind all the existing buildings with tankless heaters in a place where a heat pump retrofit is impractical. And also never mind that we already have gas fired water heaters with quite low NOx emissions and essentially zero particulate emissions.
Here in the Netherlands I'm starting to smell and hear about lots of people warming their houses by burning wood since the natural gas prices have skyrocketed. Personally I'm not too fond of the idea of breathing in more fine particulate. But trying to ban wood fire heating would be political suicide.
In the city I live in it's borderline impossible to go outside during late hours in winter because you get literally gassed with smog from the various shit people burn for heating, it's absolutely unreal.
Really? The efficiency is very low heating a house with wood unless you use it to warm water which is distributing the heat to radiators (and for heating warm water to the showers). Almost no-one who burns wood has this, people just have a chimney in the living room.
And how do you feed the wood into the burner? Waste 10 minutes every hour, 24/7?
I live in the North where -40 is common. I would say the vast majority of people have a wood stove, and they work exceedingly well.
You might not be aware but ones that burn the wood twice (even three times) are now common and in fact are law in many places. So they're MUCH more efficient, and drastically reduce the particulates coming out the stove pipe.
Another benefit is they only need to be fed once every 24-48 hours (depending on what heat you set the thermostat, what size stove you have, how well insulated your house is and what temperature it is outside.)
All it costs is your time, and not much of that since it replaces some of the time you'd otherwise spend exercising. 30hr/yr to break down a recently downed tree into firewood, 5min/day to clear out ashes and bring in new wood for the stove, and 1 min every 6hr to shove some new wood in the stove. You have gas as a more expensive fallback to keep things from freezing if you get lazy or are gone for awhile, and especially if a good job in the area pays $10/hr it's a no-brainer for most of the population to use wood heat. The stove pays for itself in less than a winter in gas savings.
I don’t have actual data, but I strongly suspect that emissions from actual well-designed wood stoves are negligible. The problem is wood-burning fireplaces, which are a whole different animal. If you want to heat your house with a high quality wood-fired heater, be my guest.
Nothing good will come of trying to heat your house with a wood-burning fireplace. They’re pretty, they’re fun, they crackle nicely, they combust wood very poorly, and they send almost all the heat right out the chimney. And, if they work correctly, lots of air comes out the chimney for the ride (keeping the combustion products out of the house), so a lot of makeup air comes in from outside, cooling your house.
If you want to heat your house by burning something, you want to capture as much of the heat of combustion as practical (preferably the higher heating value, which condensing boilers and furnaces can do, but the lower heating value is a good start), and you want to minimize the degree to which operating the heater forces you to replace conditioned air in the house with unconditioned outside air. A fireplace fails at this.
Nothing about leaf-blowers. The amount of pollution they produce is insane. Both directly by their exhaust, and secondary because they kick up a LOT of dust.
I think it might be fair to point out that particulate emissions from vehicle exhaust is likely low because of the regulation, not that they were regulating the wrong thing.
On an unrelated note, how did they come up with these numbers for percentage contribution? It seems quite difficult to attribute cause outside of a controlled laboratory setting.
Agreed, but the point here is that there are diminishing returns. Absolutely keep an eye on it, but now lets move on to the next thing that we can move the needle on.
Or pay attention to exhaust from the remaining highly polluting sources. For example, two-stroke gardening equipment (and bad four-stroke equipment), some trucks (where are the AI-powered freeway cameras detecting gross polluters), motorcycles, etc.
There are many steps that can be taken. At the moment, car designs make absolutely no effort to minimize tire particulates. I could see some basic airflow changes, along with rough filters, that could vastly reduce rubber particulates.
And the real issue isnt even the rubber but all the random chemical additives in that rubber. Some basic study and perhaps modification could also reduce impacts.
>ICE emissions will be irrelevant in 10 years when they're all but banned anyway
Dream on. Germany and EU had to pull back from the ICE ban of 2035. Banning ICE by then is unrealistic considering the way things work right now. The frog needs to be boiled slowly.
It’s hard to really quantify how big of an issue this is in my head, I mean a set of tyres will do 20,000+ miles and only loose a small percentage of their mass while doing so. How much damage is really being done? How much scope for improvement is there?
For examples, studded snow tires can tear up the road surface quite significantly, tend to kick up a lot of sharp fine dust. It's such a big problem they're often banned parts of the year in some regions where they're typically used.
It seems to largely suggest that GP is correct (see the figure in 5.3.8 for example), with the caveat that this is mainly a problem in colder regions of the world.
The road itself gets torn to pieces as well. Furthermore, tire and road wear scales with the 4th power of the vehicle mass. Heavy trucks and buses cause far more damage than cars. But all that damage leaves dust all over the road which cars will scatter all over the place.
Lastly, as pointed out above, EVs weigh a lot more, so the damage they cause will go up a lot, thanks to that 4th power scaling.
Are the two issues directly comparable? A large volume of tire particles settle near the road, going into the soil or washing into waterways for us to drink. Exhaust particles stay suspended in the air for a long time & blow far and wide for us to breathe. Both matter, both impact health, but we can't fix bad air quality by fixing tires.
Why do you believe this? It doesn't make any physical sense. Tire and resuspended road dust are in the 1-10µm range and they can fly as high and as far and for as long as a same-sized particle from exhaust.
1-10µm is a size, not a mass or chemical property. Maybe tire PM2.5 stays aloft the same amount of time as smoke PM2.5, but I don't see why that is a given.
The press on the subject also annoyingly sidesteps a direct comparison. For example, you can read that tires product 2000x the particle emissions as tailpipes, and lots of ultrafines. Notice that statement does not tell you anything about the relative difference in ultrafine production.
The media coverage on this is terrible but that is because the media is staffed full of people who did not study hard sciences. There's nothing wrong with the research on this topic and there is tons of it.
This is the most stupid thing I have read, and it makes me angry, becuase it's just the anti-electric car movement. As a person heavily affected with asthma, I get very sick whenever ICE vehicles are going nearbly, or somebody smokes a cigarette, or starts burning their furniture. I never felt sick from car tyres of electric cars.
Maybe the people who are not affected shouldn't try to guess, when many of as as we are getting older feel the difference and it affects our life.
Can you post some literature on this, as it just doesn't pass the smell test for me? At the rate I drove my old car I would have burned 1200 gallons of fuel before changing the tires on the vehicle. I find the gap here pretty hard to overcome.
Alternately, is the issue about road wear particulate as a result of tire contact? That seems more plausible to me.
EVs are not necessarily heavier than equivalent ICE cars. They are supposed to become lighter at roughly the same time they become cheaper up front, 2024-25.
But, I'm all for taxing cars for their externalities so I welcome these ridiculous anti-EV talking points. We might end up with clean EVs that are taxed by weight which is a double win.
I live on a relatively busy road in the city, cars drive around 30km/h. Doesn't feel like a big road, but lot of cars during the weekdays. After cleaning, the white elements balcony turns black every 1.5 - 2 weeks.
Dont know what it is, some people say tires. Whatever it is, it's a lot and living in cities like this have already shown a lower life expectancy of around 5 years.
Try burning it if it catches fire it's synthetic rubber natural rubber doesn't burn but does make up 25% of tires. If the debris doesn't burn either natural rubber or brake dust or a mix. Modern brake pads are ceramic or metal but not asbestos anymore. But any burning of the dust would indicate synthetic rubber is present.
In a city, its simply a combination of everything. Tires and brake dust are a small part of overall vehicle emissions. Local industry, and whatever else is on fire, are also big contributors to air pollution.
Tires and brake dust are an overwhelming majority of vehicle emissions however. When I see people this confidently wrong I always wonder if its a language model now.
"Large trucks are biggest culprits of near-road air pollution"
So black carbon from diesel truck exhaust (and buses) pollute a lot more than a lot of you think. They call it a 'soup' of pollution of both exhaust and tires. But you should continue to be skeptical of AI driven thought-content :)
Do you happen to live near anyone making alcohol? "Whisky mold" is a thing. When people talk of black material forming so quickly it is an option to consider.
In Manhattan I’d shower, take the train to work, immediately go wipe my face in the bathroom with a damp paper towel and the paper would have black smudges all over it.
Imagine the long term health implications scaled up to the whole population.
Manhattanites tend to be healthier than pretty much any other Americans. It would be logical to conclude that Manhattan is the healthiest place to spend your time.
there must be some way to manage this since I can't recall this to happen in the subways I've used (mostly munich, germany). Or I imagine what you describe a bit more dramatic than you've meant it to be
What are you on about? Before we can even start discussing any sort of cost/benefit analysis, we need to know what the costs are and what the benefits are, no? You seem to be offended by the idea of even inquiring about the costs, which is what the "Imagine the long term health implications" comment is trying to discuss.
Are you trying to say that you have already done this cost/benefit calculation and decided that there is nothing which can be done to improve the situation? If not, what are you trying to say?
An anodyne comment like "imagine the long term health implications" is not discussing anything. If you have some alternative which does less harm and the cost/benefit is better, that would be something worth reading.
We should be imagining the long-term health implications. We should be considering the costs of these things. If you don't want to think about it, you don't have to, just stay out of comment threads about it.
If you want some reading material about solutions though, there's a lot of stuff out there about reducing car reliance. Building proper public transport infrastructure, building walkable and bikeable cities, that sort of stuff. Keeping the advantages of easy and efficient transportation, while alleviating some of the disadvantages. I can suggest some if you want?
On a related note, I cycle a lot, and I wondered if the health benefits of doing so were outweighed by all the particle pollution I had to be breathing in from motor traffic. But apparently the air quality is even worse inside cars compared to outside:
Knowing what I know now I would wear an N95 if I were doing any strenuous roadside cycling. Same for yard work that stirs up a lot of dust or generally during pollen season.
"Nevertheless, we should mention that the inhalation dose of commuters could be different from the exposure levels. Dons et al. (2012) found that exposure to BC during travel in motorised transport was clearly higher than exposure while walking or biking (6.3 μg/m3 versus 3.4 μg/m3), but when accounting for inhaled doses, this relationship was reversed. Cyclists seem to receive the highest inhaled PM2.5 dose followed by bus and car passengers (McNabola et al., 2008). However, in the present study we do not examine the inhaled dose of pollutants during commuting due to the lack of studies determining it and also its complexity of interacting factors such as breathing rate, ventilation and/or particle deposition to the respiratory system."
Also, in the study, they said they drove with air-recirculation off, which I believe would mean the outside air does not get filtered. And outside air seems to be a major source of inhaled pollution, since electric vehicles have even higher measured pollution levels than gasoline.
> air-recirculation off, which I believe would mean the outside air does not get filtered
The entire point of the cabin air filter would be to filter outside air in that situation. I can’t think of a reason to have a cabin air filter that would not prioritize that situation first.
Depending on where you live may want to pay attention about general pollution. I often look at it before deciding to cycle or walk a lot, on days AQI goes up I can be occasionally coughing even without lots of physical activity
With our air quality sensor, we've noticed that there are good and bad days for air quality regardless of any other apparent factor.
We've been thinking about making the sensor portable so it can alert when it's time to mask up because its often hard to be sure if you're not being unnecessarily exposed.
Recently I went for a walk at night. It was a bit hazy in car headlights and such but foolishly I didn't think much of it. When I got home I happened to turn on a flashlight & I realized the air was full of ~1mm ash particles, I believe from a prescribed burn nearby.
The few days after that I had shortness of breath and trouble concentrating. It was pretty alarming. Not wearing a mask, which I had with me, was a big mistake.
It seems like you don't check AQI alerts in your area, so you probably did not shut your windows/doors in advance or run air filter indoors, so the exposure you get on a single walk is not as big as what accumulated in your home. That stuff you breathe day in day out and in your sleep.
So portable monitor in my view is overkill, I just check AQI in the area and close windows and run air filter indoors and don't cycle when it's bad.
But if it's a really convenient monitor I'd not mind it! In my experience accurate monitors are not small and not cheap though...
People seem to miss that better filters it is not just about higher price, but also higher CO2 emissions - filters decrease efficiency of the engine since they take energy to operate, moreover the energy consumption increases nonlinearly with decrease of particulates size. There's definitely a point where better filters don't make sense any more purelly from CO2 emissions perspective.
What do you mean? Where I'm from LPG cars are extremely popular(13.4% of all cars on the road[0]), the winters are very harsh(-20C and less isn't uncommon), and all these LPG cars drive just fine. I used to have one myself, in winter you basically had to start it on petrol but you could switch to LPG 10 seconds later and it was fine.
In the UK the main problem was that the government went with LPG conversions as the cleaner greener way forward, then got a lot of pushback from car manufacturers who wanted to sell more cars. So in the early 2000s, they pushed diesels as cleaner and more efficient and got everyone to scrap their petrol cars and buy diesels.
And you know how that worked out.
But the long and short of it is, "what happened to them?" comes down to "they didn't sell enough debt to people" is what happened to them.
Here in the US, the only LPG vehicles I've seen are forklifts and backyard hackjob conversions. My favorite one was a Subaru BRAT with the propane tank strapped into the bed.
Propane or natural gas vehicles have great emissions profiles, but unless it's a fleet operation that runs its own filling station, you're going to get range anxiety unless there's a massive uptake.
Pressurized fuel tanks have a larger safety requirement than gasoline or diesel, too; additionally, fueling accidents tend to be much higher energy. In the US, at least, the tanks expire and need to be replaced which is often uneconomical and puts a hard cap on vehicle lifetime.
In Belgium cars running on LPG cannot park in underground garages even though they go through very stringent MOT-like checks.
One of the problems is that conversions need more than just a switch of just gas to LPG. You need a tune and you need an adjustment / expansion of the cooling setup. LPG runs a lot hotter than gasoline and this needs to be managed.
Funnily enough modern gasoline engines are tuned to manage temperature by ... dumping in more fuel.
Which is why your turbocharged 3 cylinder .9L has amazing mpg while driving calmly, but once you push it it proportionally consumes way more.
You don't really need to do much. Most "modern" conversions bypass the petrol injector electrics to pick up injector pulse timing for the gas injectors, and have a separate ECU that manages the fuel mapping.
Once you've got it installed and given it an initial rough setup (not much more than programming in how many cylinders and how large an engine) it'll just trim itself. The LPG ECU maintains a map that makes the vehicle's own ECU think it's running at a perfect mixture on petrol, and is otherwise totally unaware that anything is different.
Older systems are a bit cruder, but still don't need much more than an extra lambda sensor fitted for the gas ECU.
You're still dealing with a system that expects that under certain conditions injecting MORE fuel will induce a cooling effect.
Not the case when you have an LPG system installed.
Whether the piggy-back understands this procedure and and obeys it or fakes it is irrelevant.
If your cooling system cannot handle this increased heat output you'll run into issues. Better fan will help, but again, this is more heat coming from the inside of the cylinder, so certain blocks will handle upgrades better than others.
This turns out not to be a problem, because the engine runs cooler on LPG.
The gas leaves the tank in liquid form and has to be boiled into a gas. Its boiling point is -40°C, and so the vapouriser is plumbed into the cooling system. This pulls a lot of heat out of the coolant.
I regularly tow at the maximum permitted weight and speed with my LPG-converted Range Rover, and the coolant never gets above its normal 95°C even on the hottest day.
LPG tanks in vehicles are far safer than petrol tanks.
Which is more crash-proof? A metal tank made of 5mm thick steel bolted to brackets welded into the frame of the vehicle, or a leaky plastic bucket tied underneath with a couple of straps?
Stress of fueling is probably a bigger deal than crash resistance. Most vehicles never get into a collision, and very few get into a collision where the integrity of fuel storage is an issue, but most are fueled often.
I've never seen a gasoline or diesel station have enforced safety requirements, but when I was looking at CNG cars, PG&E required pre-registration to access their fueling station, with a required fuel system safety inspection (which you can't pass with an expired tank) and a safety video. And it would be very inconvenient to drive through California without using their fueling stations.
Meanwhile, gasoline stations often run unattended, with no registration or safety inspection.
LPG is stored at about 8-10 bar. That's less pressure than is in an air suspension tank, and only about three or four times as much pressure as in the tyres.
Electric cars are clean though, you have massive improvement in air quality in cities alone.
And they are great economic opportunity since you're selling everyone a new car.
That's a massive economic boost.
Anything related to mining, well a lot of mining is bad and it's not like internal combustion engines have been all that great for the environment either. So moot imo.
Frankly I think the notion that EV is worse for the environment and battery technology being allegedly bad are just parroted talking points that negate to compare how EV would stack up to combustion technology if you applied the same number of engineering man hours to it but I digress.
Regardless propane from what I can gather isn't that much cheaper than gasoline at least for the U.S. so any potential savings in it being less expensive is easily lost by needing to burn more to go the same distance as gasoline.
Plus the conversion sounds expensive and warranty voiding. Most consumers wouldn't bother.
They're not very clean to make, which is the bigger problem.
If you convert a petrol car to run on propane, the exhaust emissions are water vapour and carbon dioxide, with no CO, no HC, and pretty much no nitrogen or sulphur oxides.
This is why things like warehouse forklifts run on propane - you can't die from breathing the exhaust fumes, unlike petrol or diesel.
Typically you'd convert older cars, of which we have plenty. We don't need to make new cars, because there are enough cars for everyone - we just need to make them run cleaner.
As I previously mentioned, it doesn't sell anyone any amount of new debt.
The whole point of "scrappage schemes" where you can scrap your dirty inefficient old car that only gets 40mpg and buy a new one that is much cleaner and more efficient at 41mpg for only 600 quid a month at 77% APR is to get people as deep into debt as possible.
Different chemistry. Petrol must be burnt quite rich in the cylinder - remember in first year chemistry in high school learning how to use a Bunsen burner? Opening up the air valve to get a bright blue flame, closing it down to get a cooler yellow flame? Anyway if you burn hydrocarbons in a fuel-rich environment you get soot and carbon monoxide - there's too much carbon for the amount of oxygen available.
Propane wants to burn leaner, and burns with a bigger, slower, and hotter bang. You can run a far leaner mixture without pre-ignition (pinking or knocking) because it's got a higher octane number, something like 115RON. You don't get anything like as much soot, you don't get any carbon monoxide, and because of the different proportions of carbon and hydrogen you get more water vapour and less carbon dioxide per mile travelled.
Exhaust filters just displace what they catch from one place to another. D/GPFs burn-off the trapped particulates in the form of soot whenever the ECU detects suitable driving conditions.
Seny Damayanti, Roy M. Harrison, Francis Pope, David C.S. Beddows,
Limited impact of diesel particle filters on road traffic emissions of ultrafine particles,
Environment International 174,
2023,
https://doi.org/10.1016/j.envint.2023.107888.
I'm convinced half of all those massive do-nothing pickups these days have hacks on their emission controls to save a few dollars per tank because to hell with pedestrians/cyclists.
It's like barely visible rolling coal and it's non-stop every time the truck is driven.
Just one mechanic sold thousands and since it's software you can be sure it's copied and used by anyone wanting to make a few dollars on the side
As a test I've pasted that into ChatGPT asking it to edit it so it uses corresponding letters from the ASCII table and it removed the strikethrough flawlessly. Probably won't be an issue for those screen readers for much longer.
Multiple physical effects are responsible for filtering. Each of them works best at certain particle diameters.
The combined efficiency of all effects happens to have a minimum at 0.3 microns. [1] This is called the "Most Penetrating Particle Size" (MPPS).
For very small particle sizes, filtering mostly works by diffusion (quoting from [2]):
>[Diffusion] is a result of the collision with gas molecules by the smallest particles, especially those below 0.1 μm in diameter. The small particles are effectively blown or bounced around and collide with the filter media fibers. This behavior is similar to Brownian motion and raises the probability that a particle will be stopped [...]
In the paper[0] they define "ultrafine emissions" as <0.1 microns.
"Diesel Oxidation Catalyst (DOC) and Diesel Particle Filter (DPF) has been very effective in controlling the emissions of solid particles and hence BC, but that there has been little change in the liquid mode (<30 nm) particles, and that concentrations of ultrafine particles (<100 nm) still well exceed the threshold for “high” concentrations (>10e4 cm^−3 /24-hour mean) defined by WHO. BC declined by 81% between 2014 and 2021, but the ultrafine particle (<100 nm) count declined by only 26%.
Looks like DPF/DOC filters use mainly interception, but they're not terribly effective at filtering via the diffusion mechanism.
- What could we demonize this month?
- Mobility is so trendy, What about car tires?
-Oh, it looks cool to me, lets do it! Let's mandate the people to walk and in a couple of months we can demonize sneakers too!
The article makes no case about car tires and specifically addresses the limitations of certain filters used on diesel engine exhaust. If you can't get behind cleaner transportation technology, try not to stand in its way.
ICE emissions will be irrelevant in 10 years when they're all but banned anyway, and rubber tyres will still be the only way to drive on the road. In fact it'll be way worse with the average EV being heavier and emitting more due to more tyre wear.