From the American Chemical Society
Green plants reduce city street pollution up to 8 times more than previously believed
Trees, bushes and other greenery growing in the concrete-and-glass canyons of cities can reduce levels of two of the most worrisome air pollutants by eight times more than previously believed, a new study has found. A report on the research appears in the ACS journal Environmental Science & Technology.
Thomas Pugh and colleagues explain that concentrations of nitrogen dioxide (NO2) and microscopic particulate matter (PM) — both of which can be harmful to human health — exceed safe levels on the streets of many cities. Past research suggested that trees and other green plants can improve urban air quality by removing those pollutants from the air. However, the improvement seemed to be small, a reduction of less than 5 percent.
The new study sought a better understanding of the effects of green plants in the sometimes stagnant air of city streets, which the authors term “urban canyons.”
The study concluded that judicious placement of grass, climbing ivy and other plants in urban canyons can reduce the concentration at street level of NO2 by as much as 40 percent and PM by 60 percent, much more than previously believed. The authors even suggest building plant-covered “green billboards” in these urban canyons to increase the amount of foliage. Trees were also shown to be effective, but only if care is taken to avoid trapping pollutants beneath their crowns.
The authors acknowledge funding from the UK Engineering and Physical Sciences Research Council Sustainable Urban Environment program.
The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 164,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.
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Only green plants? Do orange, purple, blue, …. ones have the same effect?
absolutely….grow more trees…its a no brainer
We see here educated people with no real world experience telling the average gardner or farmer or even just a person with good observational skills what they already know. Our world and our great country is entering the full stupid era as this study is somehow supposed to tell us what ? Ever drive through the desert and observe the vegetation ? The plants by the road are almost always the biggest and most green . This is do to disturbed soil , heat from the roadbed and food from the car exhaust . This has been known for so long that there is no revelation in this statement for anyone who looks. If you plant green stuff around your property and water it , it will grow and if you planted productive plants you will reap a benefit. Aint it amazing.
Makes sense. Man has a habit of underestimating nature’s ability to “scrub” itself.
And much more cost efficient than carbon credits or whatever other yoke the greenies would have us under.
Just who waould have guessed that the Romans, who mixed gardens and fountains in their cities, were so smart?
I cycle 5 miles to and from work each day in Houston. The streets with overhanging trees are cool and the ones with concrete are hot, anyone have any idea why?
Somehow common sense wore through.
Joyce Kilmer. 1886–1918
119. Trees
I THINK that I shall never see
A poem lovely as a tree.
A tree whose hungry mouth is prest
Against the sweet earth’s flowing breast;
A tree that looks at God all day, 5
And lifts her leafy arms to pray;
A tree that may in summer wear
A nest of robins in her hair;
Upon whose bosom snow has lain;
Who intimately lives with rain. 10
Poems are made by fools like me,
But only God can make a tree.
http://www.bartleby.com/104/119.html
Amen.
That is interestingly positive, plus the view is improved. However, the deciduous trees, etc lose their leaves during the winter months. Also, I have seen the roots from many types of that category of tree grow close to the surface uplifting the road surface, busting the sidewalks, and leaves clogging the storm drains. In many cases, the matching funds to improve roads or build new requires some greenery included along the paths. Nice to know there is more benefit than just aesthetics.
Can I reinvent the wheel and get paid for it?
This is obvious for people who have been in cities in other countries.
I was just delighted to see, for a change, that the word ‘pollutant’ was not referring to carbon dioxide, but instead to REAL pollutants! Is this a sign that rationality is returning to studies of the atmosphere?
/Mr Lynn
The role of vegetation in altering air composition has been known for a long time. For example, it explains why the Blue Ridge Mountains are so named.
On a larger scale, knowledge of the role of forests in absorbing or releasing gases is still very limited, especially with regard to quantity. It is not long ago that it was determined the rain forests were a major source of methane.
http://www.sciencedaily.com/releases/2006/01/060115155754.htm
We only started measuring the input and output of gases in the massive boreal forest a few years ago.
When the promoters of the Kyoto Protocol were trying to convince the US to sign on they asked what accommodation they could make. The request was for carbon credits based on replanting forests. It was rejected because they said they didn’t know how much CO2 was absorbed or released by forests.
The forgotten sphere in climate science that lies between the lithosphere and the atmosphere is the biosphere, Generally less than five meters in depth its impact on the interchange of gases, particulates, moisture is profound. There are so many gaps, not least of which is the most ubiquitous vegetation after trees, namely grasses – a major factor in urban areas. A good resource for what is known about grasslands is available at Sherwood and Craig Idso’s excellent site;
http://co2science.org/
As a measure of the problems with accurate measures of climate of the biosphere, a former technical report from the World Meteorological Organization (WMO) said a weather station in the forest required clearing a 200m area. The billions wasted on the IPCC and actions taken because of their false reports would have been better spent on obtaining more data.
1. There are people who want to put plants all over cities.
2. Research is published supporting the position of people who want to put plants all over cities.
3. Be suspicious of #2.
If their results suggested that plants helped LESS than previously believed, do you really think they would have published them? People recognize the logic of ‘follow the money,’ but frequently ignore ‘follow the ideology’ as an equal warning. Air in our cities is already dramatically cleaner than just a few decades ago, when I was a young sprout. And go back to my parent’s day, and there would have been factory smokestacks all over the city, and thousands of houses burning coal for heat in inefficient furnaces. The work of cleaning the air in cities has already been done. Any improvement now will be icing on the cake.
Wanted: Gardener/Roof Maintenance Engineer/Electrician/Plumber/Chemical Engineer for maintaining modern building roof gardens, irrigation systems, repairing electrical shorts on hi-voltage industrial A/C units, and roof leaks into upper floors, walls and office furniture/shorted office equipment (copiers, computers, servers etc.). Must be proficient at predicting chemical reactions (pH etc.) from mixtures of fertilizers and other gardening chemicals (pesticides, fungicides etc.) to minimize chemical attacks on roofing materials, conduits, plumbing and typical office furnishings (such as wallboard, paint, wall coverings, carpet etc.) and able to perform remedial operations. Knowledge of “Green” chemistry a plus. Submit your CV/resume to our web-based parser/shredder for eventual consideration.
In as much as the Australian and American Chemical Society allowed the name of their organization to be listed on Wiki with thousands of other businesses and organization as supporters of global warming alarmism I think of them mostly as the the AA Chem. Society of IPA swillers.
NO2 & volatile organic compounds (VOG) reacting in circumstances with oxygen O2 foster production of ozone (O3). The seemingly incongruous robust trees in cities among all the air pollution is due to the way that O3 upregulates production of secondary metabolites. It is primarily salicylic acid & jasmonic acid pathways which give trees what they need to overcome and thrive under oxidative stress.
Without these secondary metabolites the O3 would reduce respiration/photosynthesis & alter nutrient distribution.Early in a season, but not necessarily all season long, with high O3 around this leads to more nitrogen (N) going into the leaves. While at the same time (with high O3) there is less of a concentration of some plant phenolic glycosides being made in it’s (the tree’s) natural self-defense response a plant does when it registers bugs contact on it’s leaves.
City trees in high O3 compensate when they get low on hydroxycinnamic acid it no longer is deriving in great quantity from phenolics by up-regulatig internal production of protective iso-flavonoids. Plant O3 stress response also causes more glycosides of the quercetin group to be made for better internal cell adaptation.
Of course these are generalizations, because different tree & plant varieties (angiosperm plants have a relatively greater variety of reactions to higher O3 than gynosperm plants) will have their own particular reaction to increased O3. Since city O3 levels are an interplay of day to night changes in temperature/sunlight/VOG the dynamic is not a steady state.
Meanwhile higher CO2 levels set the stage for more C, relative to N, being processed which tends to lessen the Nitrogen in leaves. As far as the main bug defender metabolite jasmonic acid it is depressed by extra CO2, which plays out further along when there is less jasmonic acid around to boost plant’s genetic transcription of proteinase inhibitors (this is what bug would eat & suffer from in it’s bug cycles). On the other hand elevated CO2 makes a plant put out more defensive phenolics and tannins in it’s leaves, which are how plant naturally defends against relentless herbivore insects chewing attacks. To all this CO2 talk it must be added there are plant specific responses & even within the same plant variety but different genes in that plant’s makeup there are no absolutes.
Anthropogenic O3 & anthropogenic O2 apparently aren’t keeping plants from coping.
Re: Tim Ball
Let’s not forget that the canopy effect is – as I understand it – not properly considered by the GCMs. Sadly enough, land use changes (majority of which – in the GCMs – are the replacement of forest with farmland… to say nothing of the hundreds of thousands of square miles of pavement we have put down in the last 80 years or so) are calculated as having a cooling effect in the IPCC reports. The rational seems to be that forests have a lower albedo… but that neglects the canopy effect.
It’s not rocket science… which is warmer on a summer afternoon: a blacktop road, a cement road, a plowed field, pasture land, or forest?
Plants are good for all sorts of reasons 🙂
“Madrid, the capital and largest city in Spain, has more trees and green surface per inhabitant than any other European city. There’s even a jungle growing in Atocha, the main train station. But Madrid is also the third-most populous municipality in the European Union, after London and Berlin, and car congestion has led to large amounts of smog. City officials have taken major steps to combat this issue with a tree-planting campaign. Some 248,000 trees now line the streets, absorbing pollution.” Planetgreen.com 2008.
Looks like the secret is out!
Yes, it’ll be cooler too.
How much of an effect transpiration?
That reminds me of something. Don’t people also exhale water and don’t they spray water on their plants? The main thing I get out of all of this is that much of that which is called AGW is actually ALW and people conflating cities with globes while ignoring termite mounds, beehives, and a whole lot more.
Biodiesel: “NOx increases can range anywhere from less than 1 percent to 15 percent higher than petro-diesel”
One green hand gives and other takes it away …
Plants are not a “green technology” this is a manifestation of researchers egotistical know-it-all mentality into daft terminologies, In aid of funding or for the support of an undisclosed agenda I bet.
Just plant the damn trees and spare us all the idiotic wannabe science.
Trees cause acid rain through Isoprene
http://wattsupwiththat.com/2012/01/11/new-study-confirms-that-nature-is-responsible-for-90-of-the-earths-atmospheric-acidity/
Ferdinand Engelbeen : Most aerosols are of natural origin
http://acmg.seas.harvard.edu/publications/heald_2005.pdf
Trees produce lots of Isoprene.
Grow plants that produce food. So we don’t have to constantly pay more inflated prices for downsized groceries and restaurant menus if we don’t want to.
Also need to bear in mind that trees won’t survive every type of pollution. Back in the ’70s a lead smelter near Blackwell was trying to clean its reputation without cleaning its output, and planted a long avenue of poplars along the side of its facilities. The trees turned gray, bent over and died within a year, leaving a dramatic demonstration of the pollution instead of a covering shield of green.