3 ms·

> There is limited OH in the atmosphere. As a result, more methane “uses up” the OH. > So, why not produce a bunch of OH? Because OH has a half life of less th

> There is limited OH in the atmosphere. As a result, more methane “uses up” the OH. > So, why not produce a bunch of OH? Because OH has a half life of less than a second. Hmm. These two statements seem to contradict? If the chemokinetics of OH generation is less than a second, then how can it be used up in the atmosphere? Assuming the <1 second kinetic is correct, there must be a dynamic equilibrium producing it in the atmosphere to begin with. In such a case OH is not truly being used up in any real sense. It's whatever that generates OH is being used up, and that can be artificially boosted.

conradev 4y ago
One limiting factor in generating OH is specific wavelengths of light, which is harder to artificially boost
- dr_dshiv 4y ago
  Laser beams. We can only hope that this whole solution is dependent on laser beams :)
isoprophlex 4y ago
Look at it this way: there's a finite amount of OH radicals being produced each interval of time, which reacts with some CH4 and disappears in the reaction. You are correct that OH radicals regenerate, but more methane => "breakdown capacity" becomes overwhelmed. This is known as zeroth order kinetics, similar to alcohol metabolism. Drinking 2 beers = 3 hours until sobriety; 4 beers = 6 hours. Your liver has a fixed capacity, so drinking twice as much doesn't double the metabolic rate. I'll add that you're also entirely correct: if there's some long lived chemical that catalyzes OH formation, sending that up instead might be a good remedy IMO. If there's no collateral toxicity...
- quantum_magpie 4y ago
  There is no such thing as zero-order kinetics in atmospheric chemistry.
  - isoprophlex 4y ago
    But are there pseudo zero order kinetics in atmospheric chemistry? smirks
s1artibartfast 4y ago
"consumed" is better than "used up". In that <1 second, the OH can react with methane or CO. The more CO in the atmosphere, the more likely it will find the OH before the methane. It is like throwing breadcrumbs to ducks and geese. The more ducks in the pond, the less crumbs the geese will get.
quantum_magpie 4y ago
It's because that statement is incredibly wrong. Methane concentrations in atmosphere are 8 orders of magnitude higher than OH. More methane in the atmosphere has exactly 0 effect on OH. And you can't inject OH into atmosphere either because it will react with pretty much anything it comes in contact with.
- s1artibartfast 4y ago
  In this case, annual reaction mass of OH is more important than the concentration at any given time. The concentration of any highly reactive molecule will be very low, but that doesn't tell you how much was created or consumed. Methane levels don't impact OH levels (it is always consumed immediately). OH generation levels can impact methane levels. CO levels can compete with methane for OH as is it generated.

conradev 4y ago

One limiting factor in generating OH is specific wavelengths of light, which is harder to artificially boost

dr_dshiv 4y ago
Laser beams. We can only hope that this whole solution is dependent on laser beams :)

isoprophlex 4y ago

Look at it this way: there's a finite amount of OH radicals being produced each interval of time, which reacts with some CH4 and disappears in the reaction. You are correct that OH radicals regenerate, but more methane => "breakdown capacity" becomes overwhelmed. This is known as zeroth order kinetics, similar to alcohol metabolism. Drinking 2 beers = 3 hours until sobriety; 4 beers = 6 hours. Your liver has a fixed capacity, so drinking twice as much doesn't double the metabolic rate. I'll add that you're also entirely correct: if there's some long lived chemical that catalyzes OH formation, sending that up instead might be a good remedy IMO. If there's no collateral toxicity...

quantum_magpie 4y ago
There is no such thing as zero-order kinetics in atmospheric chemistry.
- isoprophlex 4y ago
  But are there pseudo zero order kinetics in atmospheric chemistry? smirks

s1artibartfast 4y ago

"consumed" is better than "used up". In that <1 second, the OH can react with methane or CO. The more CO in the atmosphere, the more likely it will find the OH before the methane. It is like throwing breadcrumbs to ducks and geese. The more ducks in the pond, the less crumbs the geese will get.

quantum_magpie 4y ago

It's because that statement is incredibly wrong. Methane concentrations in atmosphere are 8 orders of magnitude higher than OH. More methane in the atmosphere has exactly 0 effect on OH. And you can't inject OH into atmosphere either because it will react with pretty much anything it comes in contact with.

s1artibartfast 4y ago
In this case, annual reaction mass of OH is more important than the concentration at any given time. The concentration of any highly reactive molecule will be very low, but that doesn't tell you how much was created or consumed. Methane levels don't impact OH levels (it is always consumed immediately). OH generation levels can impact methane levels. CO levels can compete with methane for OH as is it generated.