Vehicles, not farms, are likely source of smog-causing ammonia

March 31, 2017 by John Schoonejongen, Princeton University
Agriculture has long been blamed for the ammonia that contributes to urban smog, but new research shows that the ammonia in hazy pollution like this in Beijing more typically comes from auto tailpipes rather than farm fields. Credit: Kang Sun, Princeton University

Agriculture has long been blamed for smog-causing ammonia in the atmosphere, but vehicle tailpipes actually are a more important source of ammonia's contribution to the haze that hovers over big cities, according to new research by a team including Princeton engineers.

"Ammonia doesn't have to come all the way from the Midwest to Philadelphia or New York," said Mark Zondlo, an associate professor of civil and environmental engineering at Princeton University. "Much of it is being generated here."

About 80 percent of airborne comes from farming practices such as fertilization, so it seems a likely suspect for the ammonia in haze particles to come from plumes of large farms in the Midwest and then get transported to the East Coast. But, in a paper published in the journal Environmental Science and Technology, Zondlo's research team found that from cities are much larger than recognized, occur at the very times when unhealthy particulate matter is at its worst, and when agricultural emissions are at daily or seasonal lows.

"It's actually coming from the vehicles" in the cities themselves, said Zondlo, who is also an associate director of external partnerships at Princeton's Andlinger Center for Energy and the Environment.

The researchers noted that vehicle emissions of ammonia were co-emitted with nitrogen oxides. These chemicals combine to form ammonium nitrate, which can be seen from the brown color in urban haze. Further, ammonia emissions from vehicles are especially important during cold weather (e.g. during winter or the morning rush hour) when agricultural emissions are at their lowest and when haze pollution is at its worst.

Daven Henze, an associate professor at University of Colorado and researcher with NASA's Health and Air Quality Applied Sciences Team, said the findings were an important step to better understanding air pollution over cities. With other vehicle emissions—mainly nitrogen and sulfur compounds—in such close proximity to the ammonia, the conditions are ripe for the production of fine particulate matter.

"It's really useful to have his [Zondlo's] work making headway on clarifying the magnitude of the source," Henze said.

To conduct his research, Zondlo and his team outfitted vehicles with sophisticated sensors to detect ammonia levels and focused on six cities—Philadelphia, Denver and Houston in the United States, and Beijing, Shijiazhuang and Baoding in China. By measuring ammonia levels during various times of the day at different points of entry into the cities, the team was able to paint a picture of a "breathing" city, where levels of pollutants rise and fall, depending on traffic and conditions.

The research was aided by the use of open-path quantum cascade laser ammonia sensors developed by Zondlo's group within Princeton's Center for Mid-Infrared Technologies for Health and the Environment (MIRTHE). The laser-based sensors were smaller, easier to work with and more accurate than previously used sensors, Zondlo said. They also allowed for more efficient mobile testing.

Previously, vehicles had to be specially outfitted for data gathering. Holes were often drilled into the bodies of the vehicles to attach sensors. Banks of equipment were needed in the vehicle as well. Because the new sensors are relatively small, they can be mounted onto a luggage rack on top of the vehicle and then plugged into a laptop. This is the basis for their Princeton Atmospheric Chemistry Experiment mobile laboratory, a conventional SUV equipped with chemical and meteorological sensors.

"Because the sensors are low power (about the same as a light bulb) and compact, we can readily deploy them on any by only adding a ski rack," Zondlo said. "Existing mobile laboratories require custom vehicles with supplementary generators and significant sampling modifications. Our sensors can be placed in checked luggage and mounted in a few hours at a field site."

That convenience led to almost immediate discovery as the data was gathered.

"You can really see the plumes coming out from the vehicles in real time," said Da Pan, a team member and fourth-year doctoral student at Princeton. "So basically you can tell if the car in front of you was in a bad operating condition. You can really see the plumes coming out from it."

Besides Zondlo and Pan, authors of the paper, which was published Nov. 29, 2016, included Denise Mauzerall, a professor of civil and environmental engineering and public and international affairs at the Woodrow Wilson School at Princeton; Kang Sun, Lei Tao, David Miller and Levi Golston of Princeton; Robert Griffin, H.W. Wallace and Yu Jun Leong of Rice University; M. Melissa Yang of NASA Langley Research Center; Yan Zhang of Nanjing P&Y Environmental Technology Co.; and Tong Zhu of Peking University.

Support for the project was provided in part by Council for International Teaching and Research at Princeton University with funds from the Fung Global Forum, National Geographic Air and Water Conservation Fund, the National Science Foundation, NASA and the Houston Endowment.

Pan said the research opens up two avenues for further study: How the proximity of ammonia and nitrogen and sulfur compounds in emissions affects production, and how the data eventually could influence regulations. Zondlo is also investigating how satellite observations of ammonia can help understand these emissions as part of the NASA Health and Air Quality Applied Sciences Team.

The efforts made to reduce nitrogen and sulfur emissions have been a big "success story," Zondlo said. Further progress in controlling particulate matter by these two species will only be incremental in the developed world.

"We've pulled these levers as much as we can," Zondlo said. "But there's one big lever that we haven't touched at all and that's been ammonia. And if we're really serious about attacking fine and improving air quality, we need to start understanding and eventually limiting these ammonia emissions."

Explore further: Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas

More information: Kang Sun et al. Vehicle Emissions as an Important Urban Ammonia Source in the United States and China, Environmental Science & Technology (2017). DOI: 10.1021/acs.est.6b02805

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30 comments

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gkam
1.7 / 5 (6) Mar 31, 2017
The need for electric transportation is obvious.

Fortunately, we are on the way to achieving it.
Eikka
3 / 5 (2) Mar 31, 2017
You know where the ammonia is coming from?

Diesel exhaust fluid in the emissions control systems of trucks is urea, which breaks down to ammonia if the catalytic reaction isn't complete - ie. when the engine is cold, or the injected amount is wrong for the load condition, or the system is over-zealous about removing NOx by injecting too much DEF.

Fortunately, we are on the way to achieving it.


How many tons of batteries would you need to move a semi? They usually carry up to 200-300 gallons of fuel and can go 1000-2000 miles on it. There's no electric car of any practical size that can go 1000 miles on a charge like a big rig should.

Eikka
3 / 5 (2) Mar 31, 2017
In light duty vehicles as well, ammonia is mainly formed in the catalytic converter. It's also ironic that increasing the sulfur content of the fuel suppresses the ammonia emissions.

http://www3.epa.g...rbin.pdf
Edenlegaia
5 / 5 (1) Apr 01, 2017
How many tons of batteries would you need to move a semi? They usually carry up to 200-300 gallons of fuel and can go 1000-2000 miles on it. There's no electric car of any practical size that can go 1000 miles on a charge like a big rig should.


YET. You can, of course, still hope for that kind of vehicles to suddenly pop out of the ground. It wont be for tomorrow. Something tells me it'll happen anyway.
But until then, the trucks will continue to use fuel, and electric transportation will still be something only people with some money to spend can afford. And that's more likely to change with time and techs than with intends.
Eikka
2.3 / 5 (3) Apr 01, 2017
YET. You can, of course, still hope for that kind of vehicles to suddenly pop out of the ground

Electric delivery vans exist.

The issue is, if a big rig has a fuel economy of 7 MPG, the chemical energy consumptions is ~4.5 kWh per mile, and actual power output somewhere around 1.5 - 1.7 kWh / mile.

With battery costs at $400/kWh a 1000 mile battery would cost at least $600,000 and with a specific energy of 250 Wh/kg it would weigh 6,000 kg. Another problem is the calendar life - lithium batteries generally don't last longer than 10 years in use. A third problem is, you just can't fill a 1.5 MWh battery out of an ordinary socket - it would literally take a week to recharge.

Tesla is "promising" to drop battery cost to $100/kWh by 2020 which would mean the battery would cost "only" $150,000 or about $15k a year, but they're not taking into account the increasing demand on raw materials if such batteries were to become in demand, which puts the price up.
Eikka
3 / 5 (2) Apr 01, 2017
If you want to "quick-charge" a 1,500 kWh battery in a couple hours, you'd have to call the local power company and give them a heads up because switching the charger on could cause their grid to trip.

One truck would pull enough power to light up a small village - about 160 average households for a 3-hour charge.
gkam
1.7 / 5 (6) Apr 01, 2017
Left unsaid is the fact farm vehicles are not covered by pollution restrictions.

And "switching the charger on could cause their grid to trip." is ridiculous.
Captain Stumpy
4.2 / 5 (5) Apr 01, 2017
@STOLEN VALOR LIAR-kam
Left unsaid is the fact farm vehicles are not covered by pollution restrictions
1- you shouldn't spread false claims as factual if you don't know WTF you're talking about

2- https://www.epa.g...quipment

3- stop spreading misinformation

per your own request to clean up the site...
gkam
1 / 5 (4) Apr 01, 2017
I checked your alleged references, and they are for stationary sources. There are no mobile source regulations listed.

Your need to get even with me has become a real problem for you.

Why don't you get help for it?

Try these breathing exercises first before posting:

https://medicalxp...ity.html
Captain Stumpy
4.3 / 5 (6) Apr 01, 2017
@STOLAN VALOR LIAR-kam
I checked your alleged references, and they are for stationary sources. There are no mobile source regulations listed.
except this
On and Off-Road equipment:
Farm vehicles, engines, equipment and fuels

Producers are subject to various mobile source requirements, similar to other similar users/operators of highway and off-road vehicles, engines, equipment, and fuel.
there are a few other links/ref's there too

...

your need to promote yourself as something special, superior or intellectual is interfering with your reading and comprehension skills

perhaps your ego is blocking your screen?

Why don't you get help for it? here is a link: http://www.readingbear.org/

per your own request to clean up the site....
Uncle Ira
4.3 / 5 (6) Apr 01, 2017
I checked your alleged references, and they are for stationary sources. There are no mobile source regulations listed.


Yeah, there are mobile source regulations listed Cher.

https://www.epa.g...quipment

Look under "On and Off-Road equipment:" Unless you are the moron you will see this link there,,,, https://www.epa.g...r-toxics

Your need to get even with me has become a real problem for you.
And being the "REAL" idiot is a "REAL" problem for you.

Why don't you get help for it?
He's trying to help you Cher, but I am afraid you are beyond redemption.

Try these breathing exercises first before posting:
Puffing on your pot pipe is how you got to where you are? Non thanks.
gkam
1 / 5 (4) Apr 01, 2017
Go to the Central Valley and see for yourself.

BTW: My car produces no emissions.

Sorry about yours.
TheGhostofOtto1923
4.2 / 5 (5) Apr 01, 2017
Holy jesus george the regs were in the next box

"Farm vehicles, engines, equipment and fuels. - Producers are subject to various mobile source requirements, similar to other similar users/operators of highway and off-road vehicles, engines, equipment, and fuel."

-You really are fucked up arent you?

I see the psychopath got the triple whammy.

So george with the MS in EM doesnt know another basic EPA reg. Proving his education is as fake as his experience is. Again.
gkam
1 / 5 (4) Apr 01, 2017
Oh, boy, another fixated sniper. "otto" and "ira" and Rumpy do not know what to do about someone who is real, as opposed to them, anonymous snipers.

They screamed "LIAR" about my proven experience in too many things to be taken any more seriously than the lies of Trump.

Get a life, "Ira", this phony one does you no good.
TheGhostofOtto1923
4 / 5 (4) Apr 01, 2017
George did you not just lie about farm vehicles? Answer the question.
Uncle Ira
4.2 / 5 (5) Apr 01, 2017
They screamed "LIAR" about my proven experience in too many things to be taken any more seriously than the lies of Trump.
Your proven experience has so far proven you to be a remarkable moron. But yeah, we don't take you any more serious than the Trump-Skippy, that part you got right.

Get a life, "Ira", this phony one does you no good.
It don't do me non harm. My bills are getting paid. My house is mostly paid for (a lot nicer than your house). I got a really good job (that I have been able to keep for almost 15 years without having to move on.)

Oh yeah, I almost forget. And I don't have to spend all day making 30 or 20 postums on the physorg everyday to "share" my "experiences" on the interweb. What you can't get anybody to listen to you in "REAL" life so you have to come here?
gkam
1 / 5 (4) Apr 01, 2017
Show me the regulations on tractor emissions.

You showed the standards for stationary sources and gasoline requirements.
TheGhostofOtto1923
3.7 / 5 (3) Apr 01, 2017
Youve got to read at least one of our posts.

"Farm vehicles, engines, equipment and fuels. - Producers are subject to various mobile source requirements, similar to other similar users/operators of highway and off-road vehicles, engines, equipment, and fuel."

Tractors are 'farm vehicles'.
gkam
1 / 5 (4) Apr 01, 2017
Oh, my, "Ira", do we have to go through all the proven facts again? Do you have to see my performance reports again, my service record, my awards, my degrees?

Do you folk understand my experiences are normal for some folk, and some of us here on the West Coast have better ones, even. Those of you in the red states think a little education makes you special, as it does where you squat. But it only makes you one of the average crowd here.

TheGhostofOtto1923
4 / 5 (4) Apr 01, 2017
Oh, my, do we have to go through all the proven facts again? Do you have to see my performance reports again, my service record, my awards, my degrees?
ahaahaaaa but you still LIED and showed you dont HAVE an education.

Youre as sick as any munchausen by proxy.
Captain Stumpy
4 / 5 (4) Apr 01, 2017
STOLEN VALOR LIAR-kam
Show me the regulations on tractor emissions
1- just because you can't read doesn't mean everyone else is equally illiterate

2- http://img.pictur...te-1.jpg

3- per your own request to clean up the site from off content sniping illiterate idiot non-science posts...
Do you folk understand my experiences are normal for some folk, and some of us here on the West Coast have better ones, even. Those of you in the red states think a little education makes you special
ROTFLMFAO
i am from the west coast, you idiot!
i don't live there now because idiots like you are far, far too abundant

ROTFLMFAO
gkam
1 / 5 (4) Apr 01, 2017
I am still looking for the exclusions. It has been a while since I checked them, and before, there were no emissions requirements for tractors or other farm vehicles not used on roads.

They have been coddled for decades.
gkam
1 / 5 (4) Apr 01, 2017
This is not about clean air requirements,is it? It is about you getting caught attacking others, and ending whatever credibility you may have had here.

When you three anonymous snipers attacked me screaming "LIAR!", and "BULLSHIT!" (remember that, otto?), it sent you crazy when I proved I really did studies and reports for NASA, really did work on rocket planes at the Air Force Flight Test Center, really did write and deliver the Power Quality set of seminars for the Electric Power Research Institute, really was a Senior Engineer for Pacific Gas & Electric, and actually did those tests on GE Boiling Water Reactors.

Sorry. I didn't mean to, . . it just happened.
TheGhostofOtto1923
4 / 5 (4) Apr 01, 2017
This is not about clean air requirements,is it? It is about you getting caught attacking others, and ending whatever credibility you may have had here
You made up a fact about tractors.

Your lie was exposed.

You claim its true because of education and experience.

But if you had education and experience you wouldnt have gotten it wrong.

This happens daily, proving how sick you are.

And we have no problem helping you make a fool out of yourself.
Captain Stumpy
4.2 / 5 (5) Apr 01, 2017
@STOLEN VALOR LIAR-kam
I am still looking for the exclusions
the only exclusions are soverign nations residing within the borders of the US, AKA- "indian" tribes

and only some of those tribes are excluded dependent upon the treaties and regulations and their tribal organizations as some tribes are included under US law and regulations
there were no emissions requirements for tractors or other farm vehicles not used on roads
false statement already proven as such above
40 CFR Part 63, and part 60

the rest of your BS posts are reported for being false claims presented as fact and argument from self-perceived authority demonstrated to be false in light of evidence that supersedes your beliefsnad statements

none of this is about "you"
it's about your false claims

per your own request to clean up the site...
gkam
1 / 5 (4) Apr 01, 2017
Fixations.

The secondary signs of psychological problems.

. . . usually preceded by hiding, withdrawal form normal society and sniping at real folk who do not have to hide from anybody.
TheGhostofOtto1923
3 / 5 (2) Apr 01, 2017
The secondary signs of psychological problems
Youre so desperate for attention that you lie in order to get it. How sick is that?
fixations
A rabid little raccoon is running around inside your house. Peoples attention tends to get fixated on that.

But i doubt the dying animal is flattered.

How come you are?
TheGhostofOtto1923
3 / 5 (2) Apr 01, 2017
A little old lady georges age ran into me recently in a walmart parking lot. She jumped out and yelled "You hit me!"

Georges brain works this way as well.

She shouldnt be driving and george shouldnt be posting for the same reasons.
24volts
5 / 5 (2) Apr 01, 2017
Gkam, Tractors and all other farm machines now have to meet the same codes as any other engines. It's been that way for over 10 years at least. Even commercial lawn mowers now have anti pollution equipment on them. Within the next couple of years you are going to see it on your lawnmower too. It's already started. It's called tier 3 and they are all now having to meet tier4 and will have to be meeting tier 5 within about 5 years. Europe has somewhat tighter standards that we do at the moment but equipment companies are mostly meeting the european standards now because it's simpler and cheaper than to run multiple manufacturing lines. There are a few places in the world that it still doesn't apply but not in the US or the European nations. The average tractor now puts out less pollution than the average gas engine car does. Look it up. It's all on line and easy to find the info.
Eikka
1 / 5 (1) Apr 02, 2017
And "switching the charger on could cause their grid to trip." is ridiculous.


Considering the "quick" charger would require around 1 megawatts of power, the local power co. will want to know when you're switching it on, so they don't mistake it as a dead short on one of the branches.

A 200 amp single phase 240 Volts connection to a house will give you 48 kW. Charging up a 1,500 kWh battery overnight (8h) would be like four homes maxing out their utility connection.

Based on average power consumption, charging up a 1,500 kWh battery in 8h is equivalent to 100 homes in California, and 75 homes in the US average, so it would literally draw power like a small town, and therefore if you stop at some small town for a recharge you may very well overwhelm their power supply.

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