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Ozone As Pesticide
Makarand writes "Purdue University researchers in the search for
alternatives to insect fumigants that damage Earth's ozone layer
have found that
ozone gas can be used as a potent
pesticide without causing any environmental harm.
Farmers could use ozone generators to get rid
of insects in their grain bins by releasing ozone
in them."
But the process won't add to the ground-level ozone that is a component of smog, they said. Maier said Purdue's ozone insecticide process uses such low concentrations of ozone that it rapidly dissipates. It would not add to ground-level ozone, which is a component of smog, he said. Can anyone clarify this reasoning? It seems to me that if a lot of farmers were using this that the 'low concentrations' at each location would add up. Yes, I know, that's only a thought experiment, but...
I want a new world. I think this one is broken.
Ozone produced near the ground does not rise into the upper atmosphere to add to the ozone layer. It will sit near the ground and if the area has weak wind currents (like many vally areas) it will stay in that area and become air polution. LA is notable as an area that has significant ozone polution.
That's correct, but the amount used here is not near enough to be toxic. However, during the summer months we routinely have smog alarms around here which caution folks to go outside for prolonged times, mostly due to the ozone in the air. It's, of course, not concentrated so high that it would kill you, but things such as severe headaches are typical issues. Note that the article states that the ozone used as a pesticide would not contribute to the overall smog problem - or at least not significantly, I think the article is not absolutely clear on that.
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this reminds me of a story I saw once on 20/20 about a type of machine that released small amounts of ozone, trying to help people with asthma. Unfortunately, it only aggravated the symptoms. So, I see big lawsuits coming from farmers with asthma. Although the article claims it won't cause environmental damage, who knows. If it stays around, though, it might just sit there, and no further treatements will be necessary. We'll just have to wait and see what happens.
Ozone might be effective and more environmentally friendly, but it might be too expensive or dangerous for widespread use. Of course, farm work has never been especially cheap or safe... this is just one aspect out of many.
If you read the article, you'd know that they intend to use the ozone gas in closed bins that store the grain.
So, they want to use ozone in a closed environment, but if this is possible, what's the harm of using CFCs in a closed environment?
CFCs are great because they act like water (as a solvent) in many ways, but have none of the harmful effects on electronic components. You can completely submerge a PC in CFCs and turn it on, without shorting anything out.
Industry used CFCs for a long time until it was linked to environmental issues. Yes, they were also used as propellents in aerosols, but why did industry drop CFCs from closed environments? They feared leakage.
So, somehow a farm's grain bin is better at keeping ozone out of the environment...go figure.
A programmer is a machine for converting coffee into code.
would not contribute to the overall smog problem - or at least not significantly, I think the article is not absolutely clear on that.
Depends on how much it's used and for how long doesn't it? In 20 years are we going to be buying ozone depleators for our homes? Are farming communities going to become little cancer farms?
Not to say I have a real problem with it as of yet, but given humanity's track record I'm not sure I share the same confidence that the perdue staff does.
Ozone is also a much better oxidant than O2. Gotta be VERY careful with that grain, a bunch of it can just burn at a smallest spark. The environment at the grain elevators also becomes much more explosive. Right now it's prohibited to smoke or create any open fire on the facilities there. Why? Because flour (it's not really flour, but microscopic particles of wheat) suspended in the air is highly explosive. Now imagine this air has high ozone content. Also, there always WILL be leaks from grain storage and ozone is poisonous.
Is the discovery that it can be used directly around foodstuffs what makes it news? I didn't even know that was a big deal, but now that I think about it, I don't recall us using those generators in the kitchen.
Ozone will break down into oxygen in 20 minutes, so smog is a non-issue. Unpainted metals, rubber (especially natural rubbers) are seriously harmed however. From the site
With very high concentrations of ozone, metals can be attacked and oxidized but are protected if they are varnished or painted. Ozone can attack natural rubber, but the synthetic rubber shows a much higher resistance. The compatibility of ozone on materials like plastics, teflon, kynar, tygon, silicone, viton and others have no noticeable effect. Most processing equipment is made out of stainless which also shows no effect.
You think that I'm crazy, you should see this guy!
In many large grain elevators inert gases such as nitrogen may be pumped into the silo's while the others gases are pumped out. N2 is pretty inert and is non-toxic. What is toxic is the lack of oxygen. Best yet, most of our atmosphere is nitrogen.
----
Go canucks, habs, and sens!
The article says "It isn't clear how the ozone kills the insects," but apparently it does, and apparently in low concentrations. We are told that it "uses such low concentrations of ozone that it rapidly dissipates. It would not add to ground-level ozone." Ah, that word "dissipates." But as Barry Commoner reminded us, "everything must go someplace." "Dissipation" isn't the same as vanishing!
And generally speaking things that kill one kind of life (e.g. insects) are hazardous to others (e.g. humans).
See this factsheet, which notes, in part:
HAZARDOUS SUBSTANCE FACT SHEET
Common Name: OZONE
CAS Number: 10028-15-6
DOT Number: None
* Ozone can affect you when breathed in.
* Ozone may cause mutations. Handle with extreme caution.
* Ozone can cause reproductive damage. Handle with extreme caution
* Repeated exposure can cause lung damage.
* ODOR THRESHOLD = 0.045 ppm.
* The range of accepted odor threshold values is quite broad. Caution should be used in relying on odor alone as a warning of potentially hazardous exposures.
WORKPLACE EXPOSURE LIMITS
OSHA: The legal airborne permissible exposure limit
(PEL) is 0.1 ppm averaged over an 8-hour workshift.
NIOSH: The recommended airborne exposure limit is 0.1 ppm which should not be exceeded at any time.
ACGIH: The recommended airborne exposure limit is 0.1 ppm averaged over an 8-hour workshift.
"How to Do Nothing," kids activities, back in print!
FYI, There has always been less ozone on the poles because there is less light there, and if the ozone layer was going away - it would go away by the ozone layer moving to lower and lower altitudes, not by dissapating. This is because most ozone is created by certain frequencies of sunlight passing through regular O2.
Arguments like the freon argument are a fraud and have much more to do with DOW chemical loosing its patent on freon and having a patent on the only known replacement then they do to do with freon destroying the layer.
Here's one hypothesis. Ozone (O_3) is really unstable and disintegrates into regular oxygen (O_2) and a nascent oxygen atom (O) at the drop of a hat. Once the ozone is inside the insect, this free oxygen radical, in search of electrons, can wreak havoc with the internal chemistry of the insect at a very fundamental level.
[unsure] Isn't it harmful even for humans to inhale ozone? [/unsure]
It's one of the main componants of summer smog and is usually the most harmful (CO and particulates are more harmful in winter). It irritates lungs and eyes.
Widespread use of ozone for pest control would probably cause more severe air quality problems in places like California's Central Valley, which already has a bad smog problem, due to its topology as well as a combination of unregulated agricultural equipment, pollution blowing in from the coastal cities (especially significant in the Sacramento Valley) and from the usual pollution that comes from any city.
I like my beverages with warning labels!
Right, or we could, you know, fix the hole in the ozone layer.
The fundamental problem[1] with the ozone layer is not a lack of ozone. Ozone is created when high-energy UV interacts with oxygen, and eventually reaches an equilibrium concentration where the rate of production equals the rate of destruction.
The "ozone hole" is a result of other chemical reactions that reduce the equilibrium O3:O2 ratio. As long as those other chemicals are present, it wouldn't do much good to dump additional ozone into the upper atmosphere.
[1] Assuming there is really a problem, and it wasn't just a convenient excuse to get CFCs off the market once their patent protection had expired.
but please keep the ozone OUT of my environment.
It's your choice whether you want to enter the silos in question.
Also, remember to stay away from power lines and electrical equipment like computers.
And it's definitely a better alternative to (non-dissipating) solutions based on Chlorine, which is another chemical which also is a good bacteria killer.
Having worked around tesla coils and other equipment that creates/gives off a lot of ozone, I can tell you, if you are going to die some way, this is probably one of the best.
:-)
You get very very high if the concentration of ozone in the air gets too high. It's a very mellow high as well.
I don't know how dangerous to your brain it is though. It hasn't caused any major problems for me yet. But around electrical equipment that gives off sparks, it's really easy to get a build up of ozone gas, or as we call it at work, happy gas.
Plus ozone definitely has a distinct smell, I find.
Just some interesting tips.
Yes though, ozone is deadly, and I am not recommending "recreational" use of ozone. I have to inhale it, you don't.
~ kjrose
You would do well to look around the various publications about CFC effects on Ozone.
CFC's are chlorine and fluorine containing hydrocarbons that were used as refrigerants, wlectronic cleaners, etc. A common CFC is Freon 12, C(F)2(Cl)2. In the atmosphere, C(F)2(Cl)2 undergoes the following reaction:
C(F)2(Cl)2 + hv -> C(F)2(Cl) + Cl
k5 = 1.0 x 10^-7 sec^-1
The Cl then reacts with O3(Ozone):
Cl + O3 -> ClO + O2
k6 = 2.1 x 10^-11 cm^3 molecule^-1 sec^-1
ClO + O -> Cl + O2
k7 = 3.8 x 10^-11 cm^3 molecule^-1 sec^-1
In short, a Chlorine breaks off of the Freon, and then just hangs around in the ozone layer, converting Ozone into Oxygen. As Chlorine is just a catalyst in this reaction, it continues breaking down Ozone as long as it is present.
It should be noted, for the sake of anyone at least somewhat versed in chemistry, that these Cl-O3 reactions may be slow, but they are still orders of magnitude faster than the O3 production reactions, which are about 10^-33 cm^6 molecule^-2 sec^-1.
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
I'm very wary of adding to ground level ozone, but if it'll eliminate that waxy sh-t from my fruits and vegetables and allow me to eat the "best part" once again, I'd consider it. The health benefits might counteract the negative.
Just a thought.
This discussion has a couple places where i see people asking, if smog is bad for people and ozone is in smog, why isn't this ozone bad for humans? Well, i would like to ask the opposite question.
I'm from Houston. I am, incidentally, at Purdue now, but that's just a coincidence. Anyway, i'm from Houston.
Houston has a *lot* of ozone in the air. Houston surpassed LA as the nation's most polluted city a couple years ago. Houston also has a *LOT* of mosquitos.
If ozone kills insects, why hasn't all the ozone in the air in Houston killed some of the insects there?
Everyone keeps saying "well, the ozone they used wasn't dense enough to be harmful to humans." So if the ozone in the air is dense enough to be harmful to humans, as it seems to be back in Houston, it should be armageddon to mosquitoes, no? And someone else said that the ozone in smog is different from normal ozone becuase it's reacted with hydrocarbons. Okay, i guess that makes sense, but now that i think about it i very clearly remember days when the Houston city government released a "ozone warning". Not a smog warning, an "ozone warning". Did they actually mean "smog which contains ozone as one of its chemical components but also contains something that makes mosquitos immortal"?
Or have the insects in big cities just built up some kind of immunity to ozone? If that's possible, what's to stop the insects that live in grain vats from building up an immunity?
What am i missing?
Irritable, left-wing and possibly humorous bumper stickers and t-shirts