Leaf enclosure measurements for determining volatile organic compound
emission capacity from Cannabis spp.
Summary
Air pollution researchers are going to pot. The expansion of legal pot farms in the 10 U.S. states and Washington, D.C., that have legalized recreational marijuana has researchers and regulators concerned about their impacts on air quality and worker health. Cannabis plants are rich sources of volatile organic compounds that can contribute to smog. One recent study suggested the more than 600 indoor pot farms located within Denver could be worsening the city’s air pollution, which already violates federal standards. Next month, in a bid to better understand that issue, Colorado officials will launch one of the largest and most sophisticated studies to date of emissions from pot farms. Such data have been scarce, largely because the federal government still considers cannabis an illegal industry. That has made it difficult for academic researchers to obtain funding or study permits from major U.S. research agencies. So scientists interested in studying pot, one researcher says, “are stuck in a position where we have to cobble this together on our own.”
- ↵* Jason Plautz is a journalist in Denver.
A B S T R A C T
The legal commercialization of Cannabis for recreational and medical use in certain US states has effectively created a new and nearly unregulated cultivation industry. Within the city limits of Denver, Colorado, there are now more than 600 registered Cannabis spp. cultivation facilities (CCFs) for recreational and medical uses, each containing thousands of plants.
Ambient measurements collected inside growing operations pre-legalization have found concentrations as high as 50–100 ppbv of terpenes; a group of highly reactive biogenic volatile organic compounds (BVOCs) and known precursors for the formation of ozone and particulate matter (PM).
Due to its illicit nature there has been insufficient experimental data produced to determine Cannabis spp. emission rates. This study used, for the first time, an enclosure chamber and live Cannabis spp. plants during a 90-day growing period consisting of four different strains of Cannabis spp.: Critical Mass, Lemon Wheel, Elephant Purple, and Rockstar Kush.
These measurements enabled characterization of terpenes and estimates of emission capacity (EC, μgC g−1 hr−1) at standard conditions. During peak growth, the percentages of individual BVOC emissions were dominated by β-myrcene (18–60%), eucalyptol (17–38%), and d-limonene (3–10%) for all strains.
Our results showed large variability in the rate and composition of terpene emissions across different strains. For the Critical Mass and Lemon Wheel, the dominant terpenoid was eucalyptol (32% and 38%), and it was β-myrcene (60% and 45%) for the Elephant Purple and Rockstar Kush. Critical Mass produced the highest terpene emission capacity (8.7 μgC g−1 hr−1) and Rockstar Kush the lowest (4.9 μgC g−1 hr−1). With 600 CCFs in Denver, and assuming 10,000 plants per CCF, an emission capacity of 8.7 μgC g−1 hr−1 would more than double the existing rate of BVOC emissions to 520 metric ton year−1.
Using Maximum Incremental Reactivity (MIR) values the total ozone formation potential from all these emitted species could produce 2100 metric tons year−1 of ozone, and based on published secondary organic aerosols yields 131 metric tons year−1 of PM. It is likely that the ECs calculated here are lower than those achieved in CCFs where growing conditions are optimized for rapid growth and higher biomass yields.
Further studies including a greater number of the 620 available Cannabis spp. strains and a wider range of treatments are needed to generate a representative dataset. Such a dataset could then better enable assessments of the potential impacts of this new industry on indoor and regional air quality.
HT/Willie Soon
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So we may have a smog problem with trees. But wait, trees are said to be very good for the planet. After all they convert that dangerous stuff CO2 back into Oxygen.
As for Heap and its cultivation, lets call in Du Pont. They dealt with the problem way back in the 1930 tees, just as the fixed the Ozone problem. True they did make a lot of money from both, but that is what Free Enterprise is all about, sarc.
As for cancer from smoking, I always thought that it was from all of the chemicals added to the cigarette to keep it burning that was the real l cause.
So now the next health scare is said to be from the vapours from plants. But what about Darwin, and evolution. All life forms including us have had millions of years to get used to it.
Finally , so we actually have a scientist doing research without a government grant. What is the scientific world coming too.
MJE
Not to worry. When everyone in Denver gets with the programme and starts smoking Cannabis, they won’t care what the smog conditions are like outside, they will all be happily stoned out of their minds in their little smoking dens.
620 varieties of marijuana! I had no idea.
I bet a lot of those are crossbreeds.
PAHomechoke probably accounts for at least 100 of them! Pennsyltucky growers are willing to take the *epsi challenge against Colombian, Peru Gold, Mexicali Red or any of that low grade crap outa Califonication any time they want to step up. City people buy importado, folks out in the world produce their own, and are quite ready to step up, yo. 😉
I have a good friend who is a Vietnam veteran and he says Vietnamese marijuana is the best in the world. He actually did a study of this issue after hearing all these claims about modern marijuana being so much more powerful than old school marijuana.
So he got hold of all the Cannabis Cup Winners (the marijuana varieties voted “best” in Amsterdam every year) for the last 15 years, and smoked them (like AK-47) and said none of them were anywhere near as potent as the Vientnamese marijuana he smoked in Vietnam.
He also said he suffered from PTSD nightmares, reliving traumatic events every night, due to his Vietnam combat experiences, but when he smokes marijuana, he does not have PTSD nightmares. He said a lot of other veterans say the same thing, although there was at least one who didn’t benefit in this way.
So if you know anyone who is suffering from PTSD nightmares, you might mention to them that marijuana might be the cure for this problem. PTSD nightmares, among other things, produces extreme sleep deprivation, which is devastating to human mental and physical health.. It’s one reason so many vets commit suicide.
Marijuana is also helping veterans kick the opiod habit. The VA is encouraging this use.
I actually do know 3 vets involved in that, and several others who learned it on their own decades ago. LTC David Grossman has done a lot of work in the field of the psychological effects of traumatic events, combat and civilian, and is an advocate of “rewiring” to handle PTSD. A multi stage process, and not “one size fits none” as most VA programs have been in the past. Long past time to get rid of what don’t work and find things that do.
And yep, this is much like to caliber debate, who has the most knockdown, who has the most penetration. Still, I will put good ole’ PA homechoke in the race with any one’s favs, and thats as detailed as I am going to get on that. 😉 Oh, and I will stick with my 147gr JHP 9mm and .30, thank you very much! They work, I am a big fan of what works.
“Still, I will put good ole’ PA homechoke in the race with any one’s favs”
I would bet that a lot of the really good homegrown varieties originated in Vietnam with vets bringing home seeds.
One interesting aspect of using marijuana to stop nightmares, was this guy said he started having these PTSD nightmares right after he had his traumatic experience, while he was still in Vietnam and a couple of months after this happened another soldier introduced him to marijuana and his nightmares went away, and he didn’t think much about it at the time thinking the nightmares were just a temporary thing.
He continued to smoke for about a year after he left Vietnam and then decided to quit in order to apply for a job that required drug testing. So he quit, and he said within about four to six weeks his nightmares were back like they never been gone. He was back to reliving the most traumatic moments in his life like it was the first time. Every night. He said he got to the point where he dreaded going to sleep, knowing what was coming. Think about trying to live like that.
Then he resumed smoking marijuana and the nightmares went away and that was when he made the connection that smoking was stopping the nightmares. He said it stopped almost all dreaming for him.
He did this same routine again, of stopping smoking, the nightmares come back in a month, then resuming smoking and the nightmares go away, so he is convinced it is the marijuana. And others say the same thing.
It makes sense that his nightmares would resume in four to six weeks, since it reportedly takes about four weeks for marijuana to work its way completely out of your system.
Sure you are right about varieties, combining different strains of plants is as natural to farm boys as breathing. Sweet corn and tomatoes are perfect examples.
I have read a great deal on treating people after traumatic events, not just vets, and lots of different outcomes from various treatment programs/systems. Not everyone reacts the same, a lesson VA has been VERY SLOW to admit to. They have long been of the “We decide what is right and you WILL DO IT our way!” school. During the last 10 years that has been changing, though there is still a great deal of resistance, in VA and the mental health field, to accepting they have been wrong. One size fits none is still VA’s default position in most facilities.
Oh, and I have known several men who went through that, 4 of them killed themselves, one in his VA doctor’s office in front of his wife and doctor. After 10 years of litigation the doctor still refused to admit his culpability in the deaths of multiple of his patients.
Not that I agree with “recreational” cannabis use in any shape or form, but this “Air Pollution” because of cannabis cultivation seems bogus to me. When it was legal to grow as a fiber crop, there were fields of the stuff everywhere for the cordage industry.
Many plants have turpines and other volatile oils, etc…Suburban micro cropping farms with Herb crops like basil, mint, lavender, rocket, etc. would be producing the same amount of “air pollution”, if not more. Not to mention Eucalyptus trees and other fire cycle foliage. Then there are everyone’s backyard gardens growing a multitude of scented plants etc. This all sounds like junk science in the name of politics to me.
The real air pollution problem arises when cannabis is burned and neurotoxic compounds are released. Passive smoke is a real problem for other people around cannabis smokers.
… So scientists interested in studying pot, one researcher says, “are stuck in a position where we have to cobble this together on our own.” …
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I think you’ll find that no one will care if you don’t.
Bad to smoke cigarettes, good to smoke pot. What gives?