Is Hot Asphalt Really Increasing Air Pollution? (usnews.com) 63
A new article examines a study which suggested fresh asphalt is "a significant, yet overlooked, source of air pollution," (as reported by Science). "In fact, the material's contribution to one kind of particulate air pollution could rival or even exceed that of cars and trucks."
UPI reports: And its emissions double as its temperature increases from 104 to 140 degrees Fahrenheit, researchers found. Sunlight plays a key role in these asphalt emissions, with even moderate levels of sunshine tripling the release of air pollutants, according to the study published Sept. 2 in the journal Science Advances... In-use pavement usually gets as hot as between 117 and 153 degrees Fahrenheit in the summer, while roofs can reach 167 degrees, the study authors said.
As the major contributors to air pollution get cut back — for example, through cleaner vehicle emissions — passive pollution sources like these will have a growing influence on the air we breathe, said Peter DeCarlo, an associate professor and air pollution expert with Johns Hopkins University, in Baltimore. "In doing that reduction, we are discovering these new sources that are now playing a more prominent role in our air pollution issues," DeCarlo said.... Asphalt probably contributes most to air pollution when it's freshly laid, DeCarlo added. During the paving process, asphalt is heated to as much as 248 to 320 degrees Fahrenheit, the researchers said. "If you've ever been around people laying asphalt, you smell it. It's clear something is getting into the air when that happens," DeCarlo said. But asphalt likely continues to emit air pollutants even after it's aged, when sunlight bakes the material, he noted.
Switching to concrete for paving would help reduce emissions, he said, but concrete is not an ideal paving material in all locales. Another possible solution might be the application of "cool pavement" technology, where colored sealants are applied to paved surfaces so they reflect more solar energy and become less likely to heat up, Gentner said. Emissions might also vary with different asphalt application methods and different formulations of the paving product, Gentner suggested.
UPI reports: And its emissions double as its temperature increases from 104 to 140 degrees Fahrenheit, researchers found. Sunlight plays a key role in these asphalt emissions, with even moderate levels of sunshine tripling the release of air pollutants, according to the study published Sept. 2 in the journal Science Advances... In-use pavement usually gets as hot as between 117 and 153 degrees Fahrenheit in the summer, while roofs can reach 167 degrees, the study authors said.
As the major contributors to air pollution get cut back — for example, through cleaner vehicle emissions — passive pollution sources like these will have a growing influence on the air we breathe, said Peter DeCarlo, an associate professor and air pollution expert with Johns Hopkins University, in Baltimore. "In doing that reduction, we are discovering these new sources that are now playing a more prominent role in our air pollution issues," DeCarlo said.... Asphalt probably contributes most to air pollution when it's freshly laid, DeCarlo added. During the paving process, asphalt is heated to as much as 248 to 320 degrees Fahrenheit, the researchers said. "If you've ever been around people laying asphalt, you smell it. It's clear something is getting into the air when that happens," DeCarlo said. But asphalt likely continues to emit air pollutants even after it's aged, when sunlight bakes the material, he noted.
Switching to concrete for paving would help reduce emissions, he said, but concrete is not an ideal paving material in all locales. Another possible solution might be the application of "cool pavement" technology, where colored sealants are applied to paved surfaces so they reflect more solar energy and become less likely to heat up, Gentner said. Emissions might also vary with different asphalt application methods and different formulations of the paving product, Gentner suggested.
Yes, but so is concrete (Score:5, Funny)
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Yea but asphalt smells the worst. All-concrete roads on the other hand can act as carbon syncs, and are almost completely odorless in all temperatures, wet or dry. They would use it everywhere except that asphalt is cheaper and faster, despite being smelly, ugly, and less durable, that's all. Asphalt is also basically made from the same stuff as the tires and the fuel going into the engines so there's some clear conflict of interest here.
Re:Yes, but so is concrete (Score:4, Informative)
All-concrete roads on the other hand can act as carbon syncs
Concrete is the most destructive material on the planet [theguardian.com] due to its manufacturing process, water usage and carbon dioxide emissions.
There is a stretch of highway about an hour from me which is all concrete. Every single slab has a dip in its middle. Your car goes up and down like you're riding over low hills. Imagine this going on mile after mile. One could conceivably get seasick from the motion.
This doesn't get into the noise of driving on concrete or the danger when the surface gets wet or is cold. Slip sliding away is the mantra when driving on concrete roads.
The one advantage concrete has over asphalt is it doesn't get as hot. Asphalt, being black, increases atmospheric temperatures far more than concrete.
Re:Yes, but so is concrete (Score:4, Informative)
Not for nothing, concrete roads are significantly more durable than asphalt paved through ways, lasting 20-40 years(2-4 times the lifespan of asphalt)... the expense is the biggest drawback.
Double the initial construction cost [chicagotribune.com] is a huge budgeting consideration. Although the math plays out over the long haul, municipal and state governors are seldom around, or given credit for, payouts past their respective times in office.
Not to mention, there's a good bit of pork in the roadway construction industry, and the major players would much rather install a surface that will need resurfacing in 5-10 years, as opposed to 15-25 years.
Re: Yes, but so is concrete (Score:2)
Concrete freeways in L.A. do not last very long before breaking down.
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Not for nothing, concrete roads are significantly more durable than asphalt paved through ways, lasting 20-40 years(2-4 times the lifespan of asphalt)... the expense is the biggest drawback.
Fuuuuuuck that.
The concrete road I'm familiar with is the US-101 as it goes through nocal from a bit north of Marin to up past Ukiah. It is shit, easily some of the worst road in California, which is chock-full of bad roads. In most vehicles, driving on it at speed is a bit like riding a mechanical bull. It's not too horrible in my current Mercedes (ye olde '82 300SD, which has Bilstein HD shocks), and it's bearable in our other Mercedes (a Sprinter) but it was terrible in our Astro, and awful in my Impreza
Re: Yes, but so is concrete (Score:5, Informative)
" They would use it everywhere except that asphalt is cheaper and faster"
The cost is a surprisingly small part of it. While asphalt roads are cheaper to lay down, they also don't last as long before they need replacement.
The main reason we use asphalt for most roads is freeze tolerance and maintenance time.
Modern asphalt formations are able to be and flex even at low temperatures, preventing freeze damage and cracking that can result in total failure the next season. Concrete is laid in small individual blocks that have filled expansion joints in between them to allow for needed expansion and contraction. The problem with that is when the elastomer dries out and cracks, road authorities don't get it sealed in time, letting water get to the underlay. Once water penetrates the roadbed, you are counting down to the toad's destruction.
Additionally, concrete roads need to be cured for an extend period of time after laying, requiring road or at least lane closures durring any maintenance. Asphalt can be driven on within minutes of being laid. Making it much more maintenance friendly.
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I'm surprised we haven't come up with something better by now. I guess poured stone rules. And petro-refining offal. I remember a city worker telling me about the tar(?) slurry used to periodically seal the asphalt streets. It works for a few years--it covers and smooths out street repairs, pipe trenching, cracks, etc. He said it was a ripoff. Maybe. It does use a substance that otherwise might not have any use.
And, probably, politics.
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I'm surprised we haven't come up with something better by now.
Better than reusing a waste manufacturing product? The problem is that "better" is not an arbitrary yes or no. "Better" may be classed in any of 10s to 100s of different characteristics in 100s of different situations. For example there are *many* different formations of asphalt to suit a wide variety of different climates, so even asphalt isn't an all encompassing product. It's like saying we haven't come up with something better than "fuel" in a machine yet, without discussing diesel, jet, gasoline, or an
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No that is a huge and blatant lie. Bitumen is made from anything, it is the rubbish left over after the refining process has sucked everything they can sell out of it (well just as much as they economically can.)
Quality control, checks for toxicity, anything what so ever to check it, ZERO, nothing what so ever is done to check the level of heavy metals, carcinogens, every kind of now concentrated pollutant you can imagine but can not check, it is just refinery left overs, USE IT AT YOUR RISK.
I checked becau
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Check asphalt for carcinogens? It's primary components are known carcinogens. But then people aren't expected to eat it, or drink it.
You did mention that people could breathe in the particles. Any idea how much?
California has a law where anything with a known carcinogen in it has to be labeled as such. It's a joke of a law because if people look hard enough then everything contains something carcinogenic. It's not enough to point out that asphalt contains carcinogens, you have to put some kind of numbe
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I lived on a main road once, the was definitely a grit associated with the pollutants. It's driving that is problematic, everyone is stirring that stuff up and inhaling it and it really depends upon how problematic that lump was, where the oil came from, what was in it and what was left. Like all cancers, it is all down the probabilities, the right combination of damage to reproduce a cell, that functions as a cancer, can happen on the first bit of damage or take decades for the fates to roll against you. E
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But to the GP's assessment, this is just baseless conclusions. I can just as easily make other statements like the afternoon sun shining down on a dirt road vs an asphalt is the highest risk in the environment. Maybe its the background radiation or the number of bananas eaten by the individuals. I am pretty sure asphalt after a week is fairly safe compared to all the factors we run into. The post even mentions that basically once we start curtailing the main culprits of today, the _next_ layer of culpri
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Conflict of interest or taking advantage of a pre-existing supply chain? "Synergy", for all you buzzword bingo fans.
Probably a mixture.
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All-concrete roads on the other hand can act as carbon syncs
You're woefully uninformed. The concrete production is enough of a carbon contributor that it has it's own category in climate change discussions.
except that asphalt is cheaper and faster, despite being smelly, ugly, and less durable, that's all
Actually that is not all. Asphalt also offers far better handling characteristics when worn (beaten by concrete when freshly laid), better environmental characteristics with wider useful temperature ranges, orders of magnitude better drainage characteristics which leads to a very significant increase in road safety in wet weather, and significantly better audible
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Some things are just more complex than you understand.
I'm sorry, but you just carefully laid out an argument for spreading the waste material from fuel processing around the whole planet instead of sequestering it somewhere in a conversation thread about how it is literally the thing killing us all, and you think I'm the one who doesn't understand the big picture here? Fuck off.
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Yes I did. You see you use the word "waste" with some kind of negative connotation, rather than the fact that all it is is a product with different properties. Butane and Propane are also "waste" products from fuel refining, as is PET. Are you suggesting we therefore give up the use of plastic or stop using gas fired BBQs just because you don't like the term "waste" and don't feel like understanding what it means to reuse a waste product?
Come back when you can offer an alternative that is environmentally fr
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As far as I know, conventional concrete manufacture is a significant CO2 emitter. I believe there are low carbon concrete processes, but I do not understand the chemistry.
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Even leaving them bare dirt would increase pollution, since it would take vehicles more effort to move on that.
I grew up on dirt roads, this made me laugh because the dirt that gets kicked up is far worse than whatever the difference in emissions is between pavement and dirt roads. Not to mention the fact that drag isn't a problem at dirt road speeds, so I'm not so sure you can really say the emissions would be worse, but the air quality definitely is worse.
Re:Yes, but so is concrete (Score:5, Informative)
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If this was in Texas, it was very likely used transformer oil from the power company, and it was loaded with PCBs. Some of the most toxic stuff around and they were spraying it on the roads.
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They also spray dirt roads with brine from oil drilling and fracking so it's covered with toxic and radioactive shit that still gets kicked up into the air or washed down with rain into the groundwater. Cool!
https://www.post-gazette.com/b... [post-gazette.com]
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Not just that, but there are already radioactives in dirt. The place I've driven with the most dirt roads is highly volcanically active (Lake county, in California.) You don't really want to be kicking that stuff up into the air. As it is they "salt" the roads with volcanic cinders, which is nice in that it produces less vehicle corrosion than actual salt but it's nothing you really want to be breathing either as it contains silicates.
Paving roads is clearly the way to go. But equally, using rail where poss
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I love dirt roads. Woe to tailend Charlie!
Or we could, and I'm just spitballing here (Score:2)
One of the things I've notice of late, even here on
As a result people are looking more and more to the past for answers, which is in general not a good idea. You can learn from the past, but it's really easy to become a slave to it. Before you know it you've got a new "Dark Ages" because nobody wants to change anything.
Cancer? (Score:2)
Maybe not. The US uses 20% of the world's asphalt supply (other developed nations may not be far behind, with higher population densities). Maybe the emission of volatiles is partly behind the observed rise (*) in several cancer rates in the past several decades ?
(*) - after adjusting for age, longer lifespans, better medical surveillance, etc.
Yeah but there's a far more serious issue (Score:1, Offtopic)
How much CO2 is emitted by Editors reposting stories, and how much electricity is wasted on displaying dupes.
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Since when is pointing out a dupe off-topic? Did Slashdot give some newbies modpoints?
Dupe Alert! (Score:5, Informative)
Is hot asphalt producing dupes?
https://science.slashdot.org/s... [slashdot.org]
It's not just the same story, it's the same exact article.
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But hey the Slashdot swag store is back online! YAY
Maybe if you buy some crap you'd be embarrassed to wear in public, the site would be better! Or not.
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I did.
Slashdot is niche enough these days that nobody is going to look it up and give me an odd stare. They're going to hear, "tech/politics/science news debate club", and keep right on doing whatever else they do.
I'm pretty excited for my Slashdot stickers and clothes. I hope they're making enough off my purchase that it's doing something to help fund the site.
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The next dupe is just for you, pal.
Re:Dupe Alert! (Score:5, Funny)
Re: Dupe Alert! (Score:2)
You're just being an ash.
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Hot-ass phalt.
https://xkcd.com/37/ [xkcd.com]
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It's not just the same story, it's the same exact article.
But look at all of the human EFFORT and TOIL we've saved by recycling that article, and not using paper and printing presses to research(!), create, proofread, print, and then deliver these duplicates. Why, we've saved TENS of milli-watts doing things this way!
As the major contributors to air pollution get cut back ... passive pollution sources like these will have a growing influence
Wow, the intelligence it takes to figure that one out. Why, it's like the top-10 pollutant list will always be filled with something. OTOH, there are probably some people who probably didn't even think of that, so it might be a good thing he's actu
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Oh well since you put it that way . . .
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What did you expect? Most of it's recycled after all.
https://en.wikipedia.org/wiki/... [wikipedia.org]
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Fitting. Can we recycle the editors?
Who needs pavement? (Score:2)
Just do away with it [tumblr.com].
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But what they don't tell you is that's where the truck broke down :)
The most popular trucks are Ford, Chevy, and Dodge in that order. On the side of the road I see Chevy, Dodge, and Ford in that order. Seems like the most reliable truck is a Ford. How weird.
Slow newsday - no science to see here (Score:2)
On slow newsdays on Slashdot, EditorDavid finds the dregs at the bottom of the barrel and posts them. They're usually inane, not relevant, and hardly slashdot material. Like this [duplicate] article. From the most reliable news source - US News - Not.
Concrete puts out so much CO2 and pollutants that cities are trying to use less, not more. It costs 10x as much to create pavement out of concrete than asphalt, and heat cycle crack it.
NOBODY in their right mind except the concrete industry would suggest re
Vacuum tubes ? (Score:2)
Vegetarian and Vegan Flatulence (Score:1, Troll)
Asphalt comes in natural deposits (Score:2)
So it's as natural as a generic tar pit.
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yeah.
does the article have some more argument than "it smells" ?
I don't recall asphalt workers being in a huge cancer risk either.
also asphalt heating up is an advantage in near winter conditions.
also it's highly recyclable.
do they even specify the pollution? how much is the pollution compared to particles from TIRES? not much I imagine.
Better idea (Score:1)
Use more carbon negative concrete. (Score:4, Interesting)
I remember reading an article on carbon negative concrete by Prof. Darryl Siemer at Idaho State University. Look him up if you like but further research on this told me that many others had the same idea, though perhaps not in as much detail.
The idea came in two parts, lower CO2 emissions from energy and using raw materials for concrete that were carbon sinks. He recommended nuclear power for lowering CO2 emissions but any low CO2 energy source helps.
The big part of the plan is to use basalt for the source of sand and calcium oxide in cement. Use crushed basalt for aggregate for additional carbon capture. The key to Portland cement is the use of lime, or calcium oxide, which will harden as it takes in CO2 from the air and turn into more durable limestone. The primary source of lime for cement today is limestone mines, and the limestone is heated to release this captured CO2 into the air to become lime. Basalt is a natural source of lime as it is a rock that has not been exposed to the air long enough to turn into limestone. There's a lot of basalt in the world, in easy to reach places, so we aren't going to run out of the stuff.
The reason we use limestone instead of basalt is because limestone is "soft", or as soft as rocks get. Basalt is a "hard" rock that wears out drill bits and other tools to mine it more quickly than limestone. Because basalt is a mix of many minerals it means more work in mixing the cement consistently than using limestone, which is found naturally with high purity and consistency.
This comes down to costs if we are to replace asphalt. We need to find a way to make basalt based concrete cheaper than asphalt and limestone based concrete. Prof. Siemer and others seem to think this is possible.
Plant more trees (Score:1)
In CA, Likely More Solar Heat Issues (Score:2)
Heat (Score:2)
A more important issue is the potentially large contribution of asphalt to urban heat, compared to light-colored surfaces such as concrete. That increases power usage during the summer, not only costing people more money, but increasing the chances for unscheduled power outages.
Plant shading street trees (Score:2)
The real question? (Score:1)
Are (so-called) journalists farts that they are sucking out of each other's asses, swallowing, and then belching up contributing to pollution? The answer: YES! Kill a so-called journalist today and stop pollution. It's the right thing to do!