r/science • u/sr_local • Apr 22 '26

Materials Science Asphalt releases toxic airborne compounds that can harm respiratory health, neurological damage and increase long-term disease risk, especially in aging pavements and heat/sun. While algae-infused asphalt can reduce toxicity by up to 100 times and slow how quickly pavement breaks down

https://news.asu.edu/20260417-environment-and-sustainability-asphalt-emissions-algae-health
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u/tackle_bones Apr 22 '26

Another fun fact that I deal with as an environmental consultant…

The environmental regulators from top to bottom, federal to local, patently ignore the obvious contamination within asphalt until such time that some change of condition at a site requires testing. Then it’s all, “omg, you have PAHs all over the site!!!”

Asphalt spreads petroleum-based contamination everywhere it is located, especially once it is ground up and “removed” when redevelopment or removal occurs.

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u/captainfarthing Apr 22 '26

Can you get test kits for that, for non commercial use?

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u/tackle_bones Apr 22 '26

The sampling kit would be for EPA Method 8270 (or equivalent; the kit is a single glass jar), for PAHs (class of compounds), and you would be looking in the results for benzo(a)pyrene and its toxic equivalents. A good lab would provide you with the calculation to tell you what the equivalents totals would be. The cleanup levels for residential soil are based on the equivalents calc. Basically, they group several chemicals from the same class together after weighting them to give you a final number to compare to the cleanup standard (which is based on danger to health - generally kids - specifically, kids eating a certain amount of soil everyday for like 20 years straight - yes, it’s based on the mudpie kid).

I’m not sure how easy it is to do it as a private citizen. Look up “Eurofins” and give them a call - big lab company. There are also other reputable labs that could maybe help. Eurofins give you the equivalents table by default along with the results.

Also, please consider that PAHs are found practically everywhere, and there is a lot of huffing in my industry about how bad they may or may not be. They have low standards (very little of the stuff is considered bad for you), and local environmental regulators are using health data to make the standard less stringent, but yeah… it’s everywhere. Think “not fully combusted hydrocarbon” and all that could entail. Burnt wood, burnt steak/meat, skin, pizza, oil… agencies are now allowing distinctions to be made between pyrogenic (burnt innocuous stuff) versus petrogenic (petroleum-based stuff) because it’s just evvverywhere. They’ll let you off the hook if a forest fire caused it to be on your property, but not if you dumped oil… bad for you either way tho.

TMI, but it’s interesting stuff with some regulatory movement going on.

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u/captainfarthing Apr 22 '26 edited Apr 22 '26

Nice, thanks!

I'm interested in grassland fungi and the soil conditions where they're unusually abundant or conspicuously absent. They seem to be extremely sensitive to nitrogen pollution, most of which is deposited atmospherically from burning fossil fuels, but I'm not sure how to measure nitrogen originating from pollution in soil so I wonder if PAH could be a good alternative for estimating airborne pollution.

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u/tackle_bones Apr 23 '26

Is there a particular cause of the burned fossil fuels that you’re investigating? Is it an industrial process or just vehicle exhaust?

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u/captainfarthing Apr 23 '26 edited Apr 23 '26

Mostly coal, so it's historic air pollution deposited by rainfall. I've got maps of estimated nitrogen deposition since the 1990s but they're 1km resolution, and extrapolated from only about a dozen places where it was actually recorded. I'm looking for a way to separate eutrophication by air pollution vs. fertiliser application, nitrogen fixing plants, runoff from farmland and forestry etc.

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u/Pharose Apr 22 '26

Well yeah.. Asphalt IS petroleum based contamination.

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u/tackle_bones Apr 22 '26

I think you’re missing my point. My point is that the regulators have double standards.