#anlooh — Public Fediverse posts

The introduction of this 2024 preprint explains the basics regarding OHradicals, NOx, ozone, and methane.
#Mertens et al "The contribution of transport emissions to ozone mixing ratios and methane lifetime in 2015 and 2050 in the Shared Socioeconomic Pathways "
https://egusphere.copernicus.org/preprints/2024/egusphere-2024-324/
A term I don't really understand: Volative organic compounds, VOC
https://en.wikipedia.org/wiki/Volatile_organic_compound
Until I do I translate the term with "plant pheromones".

Tropospheric ozone is a people & plant killer and a #greenhousegas.
Ozone is needed to form OH radicals – which are needed to break down methane. When ozone is less abundant in the lower atmosphere=troposphere, OH radicals are also fewer, and CH4 lifetime is longer.

Interesting:
#Ozone concentration follows 2 formation pathways:
a) #NOx is hit by UV light
b) VOC are hit by UV.
When NOx concentration is low, ozone isn't automatically low in tandem. Because in our world today, if NOx is low = away from cities and fossil fuel combustion, the abundance of plant pheromones VOC is high and ozone just forms this way.

During COVID lockdowns:
"although NOx emissions were greatly reduced, measurements and results of model simulations showed only a slight decrease in O3 or, in some cases, regionally increasing O3 values."

Ah. Let's have a quick look at some old charts of CH4 measured in European stations in the ICOS network....

#anloCH4 #anloOH

Can we deliberately increase #methane destruction by OH radicals?
In the Northern mid to high latitudes #CH4 concentration near ground is the highest. 2200ppb is not a rare event in #ICOS measuring stations around Europe.
So deploying our radicals would be more efficient there.
What do we already have that has NOx aplenty and can be bombarded with UV to create OH?
Maybe every greenhouse in the Netherlands.. Oh, is UV and ozone bad for plants? Ozone is the step between NOx and OH.

Workers in the greenhouses would have to wear WW2 gas masks and full body lead suits, would they not...
uhm.
So better no UV in a walled-in room like a greenhouse.

In case UV is not bad for plants,

we can fasten UV lights underneath #agriPV where wind dissipates the toxic ozone !
And where wind also automatically replenishes CH4 and NOx.

And for maximum usefulness, the UV lights are cased in with a thin wire mesh on which the water vapour can condensate that is a byproduct of the CH4 bombing. The droplets are then channelled into ground water. Or pipelined to Southern Europe.

Ah. even better.
AgriPV with UV underneath directly in Southern Europe, where the harvested water can also be used directly.
#anloCH4 #anloOH

OH radicals are born if NOx is hit by UV radiation in sunlight. (And water vapour in the air reduces this OH-birthing process, see posts above.) OH Radicals only have a very short lifetime of less than a few seconds because they bomb anything to bits that comes their way, or rather, they react with anything in their neighborhood. If a #methane molecule is bombed by OH radicals, the result is water vapour and CO2.

NOx is born in cow and pig shit, in artificial fertilizer, and also in high-heat combustion processes like lightening strikes, forest fires, and cars, trucks, planes, and ships.

NOx and the chemicals born when NOx is hit by UV sunlight (eg ozone), are harmful to living beings. So anthropogenic NOx gets reduced technologically after national and regional #CleanAir regulations. And by the international shipping organisation IMO, see eg https://www.ukpandi.com/news-and-resources/articles/2022/imo-tier-iii-nitrogen-oxide-nox-emission-compliance/ It also describes some techy ways for reducing NOx emissions during fuel combustion.

IIUC, #diesel engines burn fuel at higher heat than Otto motors. This makes diesel motors more efficient, leading to less CO2 emissions per km – but to more #NOx. Which must then be scrubbed from the exhaust.

We all recall the two (!) diesel scandals 2004 and 2015 where European car industry was found to cheat deliberately wrt NOx from diesel. (Cheating isn't the right word when you consider that people get sick and die from NOx' ozone pollution. Hence the regulations. And people with the car industry know this – so their cheating is really murder according to German law and recent verdicts [on other cases but with similar circumstances relevant to the legal definition of #murder].
The fact that German state attorneys chose to only prosecute the fraud speaks volumes wrt how car-centred their minds work. IMO, those managers and engineers should spend their lives in a prison cell. #Dieselgate #CleanDiesel Together with the software manufacturers at #Bosch, and the Rex Tillersons of this world. #ExxonKnew
Murderous cheating wrt Otto motors is also known https://de.wikipedia.org/wiki/Abgasskandal#Manipulation_bei_Fahrzeugen_mit_Ottomotoren
Here it is a software for reducing #CO2 emissions on the testing stand. )

Anyway. Where was I?
Ah, yes, the NOx-creation process and how these give birth to OH radicals in UV sunlight: OH radicals are born when UV sunlight hits NOx molecules. After only a few seconds, the suicidal radical bombs a suitable molecule like methane. But new radicals are born all day long. Because NOx is replenished constantly, in lightening strikes, forest fires, burning fossil fuels in🏭🏠, and:🚗🚚✈️🚢

Together with the new finding that more moisture in the air due to global warming reduces UV sunlight, and hence reduces the births of OH radicals, which in turn increases CH4 lifetime https://www.science.org/doi/10.1126/science.adn0415 #Prather et al 2024🔒
I have been also wondering for a few years now whether NOx regulations and technological scrubbing (where it does occur, harr harr), and also a serious electrification in transport, industry and homes already have, and will have later on, a sufficiently large effect on increasing CH4 lifetime.

And I am wondering again whether a reduced NOx abundance during the warm=wet and less fire-prone, stronger forested #Miocene caused CH4 to linger for longer because fewer OH radicals were born.
Adding the new finding to this theory, that more water vapour decreases OH concentration, makes my theory even more pertinent:
With high temperatures during the miocene at surprisingly low CO2 values, methane could explain parts of the discrepancy. But we don't have proxies for methane concentration.
Kind of important because today's climate sensitivity for doubling CO2 = 3°C, is in part fed by findings in #paleoclimate such as the Miocene.

The Miocene had a different land mass layout, different ocean currents, and also different biomes, hydrological cycle and whatnot.
So it's not a good analog for our experiment today as I often point out, eg in this thread https://climatejustice.social/@anlomedad/112767092856263574
It's also mentioned in passing in Gavin Schmidt's new blog post about the paper that had prompted my thread above, with its spurious claim of climate sensitivity. https://www.realclimate.org/index.php/archives/2024/08/oh-my-oh-miocene/#ITEM-25598-4

So these system setting differences explain part of the temperature/CO2 discrepancy.
But not all.
#anloCH4 #anloOH

The study on how increased water vapour reduces the concentration of OH radicals by filtering UV-light, and thus,
extending the lifetime of #methane in the #atmosphere: https://www.science.org/doi/10.1126/science.adn0415 🔒
#Prather et al 2024 "Resetting tropospheric OH and CH4 lifetime with ultraviolet H2O absorption"

A side note:
The suggested replacement of hard-to-abate fossil fuels with hydrogen in steel industry or shipping, makes the discovery of the connection
water vapour ↘️ OH radicals ↗️ CH4 lifetime

even worse.
Considering that #climateChange increases methane emissions from natural sources due to more wetlands and thawing permafrost becoming active peat land,
we're all the more dependent on OH radicals bombing CH4 molecules to bits.

But the leaky supply chain of hydrogen will further increase water vapour – by also using up OH radicals for this reaction – hence, serious use of hydrogen in industry or heavy transport will further decrease OH concentration,

which is already decreasing due to warmer air holding more moisture, as the study apparently shows. #Openaccess should be mandatory!!
#anloCH4 #anloOH