Featured Research

from universities, journals, and other organizations

Ammonia air pollution from cars and trucks worse in winter

Date:
October 19, 2011
Source:
Rice University
Summary:
Motor vehicles and industry are primary producers of ammonia in Houston's atmosphere, and cars and trucks appear to boost their output during the winter, according to a new study.

Motor vehicles and industry are primary producers of ammonia in Houston's atmosphere, and cars and trucks appear to boost their output during the winter, according to a new study.
Credit: VanHart / Fotolia

Motor vehicles and industry are primary producers of ammonia in Houston's atmosphere, and cars and trucks appear to boost their output during the winter, according to a new study by researchers at Rice University and the University of Houston (UH).

Related Articles


Ammonia's role in air quality draws minimal oversight from the Environmental Protection Agency (EPA), but researchers at both Houston institutions are learning what it means to life in and around the metropolis.

The study led by Rice Professors Robert Griffin and Frank Tittel in collaboration with UH researcher James Flynn and Professor Barry Lefer revealed the seasons play a role in ammonia produced by vehicles. Their instruments also measured plumes of airborne ammonia from isolated incidents. The results appeared in a recent research paper in the journal Atmospheric Chemistry and Physics.

The findings are not cause for immediate concern, said Griffin, an associate professor of civil and environmental engineering. "There may not be a health risk from ammonia itself, but the fact that ammonia is a precursor to particles is a big deal. They can get into your lungs and do some damage."

Ammonia quickly combines with other airborne elements: sulfuric acid to make ammonium sulfate salts or, in cooler conditions, nitric acid to make ammonium nitrate. The particles could impact air quality as well as atmospheric visibility, cloud formation, climate patterns and nutrient cycling, he said.

Ammonia is found throughout the atmosphere in levels ranging from parts per trillion to parts per billion (ppb), he said. People can detect ammonia at five to 50 parts per million (ppm). Concentrations above 100 ppm are uncomfortable to most, according to the EPA.

The sources are many: industry, motor vehicles, agriculture (as a major component of fertilizer) and livestock. Even humans produce ammonia. (Household ammonia is highly diluted with water -- but one should still avoid the pungent fumes.)

Wondering how much ammonia is in the atmosphere at any given time, the researchers gathered data 24 hours a day over two weeks in February and six weeks in late summer, 2010.

Readings were taken atop the University of Houston's tallest building, North Moody Tower. The residence hall is ideally situated to pick up changes in the wind not only from the nearby Houston Ship Channel and its associated industries to the east, but also power generation facilities to the southwest and Houston traffic in every direction.

Tittel, a pioneer in laser sensing and Rice's J.S. Abercrombie Professor of Electrical and Computer Engineering, and Rafal Lewicki, a co-author and graduate student in Tittel's laser science group, designed and built an apparatus to collect the data. Their external-cavity quantum cascade laser-based sensor is finely tuned to pick up signs of ammonia from air samples continuously cycled through the closed system. Real-time readings were taken with a resolution of less than five parts per billion and autonomously monitored at Rice via the Internet.

Sampling at a single site produced results that at first seemed contradictory, Griffin said.

For example, while overall levels were highest in the summer, ammonia emissions from vehicles were found to be highest in winter when harder-working car and truck engines reduced the performance of catalytic converters. (Carbon monoxide levels recorded by UH instruments on the tower correlated nicely, the study showed.)

Part of the answer was blowing in the wind. The researchers found the prevailing wind during winter morning rush hours came from the southeast -- past several major highways and Houston's William P. Hobby Airport -- and carried a high level of vehicle emissions.

During summer morning rush hours, the wind whistled in from the northeast, passing the ship channel and increasing readings from industrial activity and including occasional spikes, including a nearby traffic accident, that raised the average.

Winter levels of airborne ammonia ranged from 0.1 to 8.7 ppb with a mean of 2.4 ppb. A larger range -- 0.2 to 27.1 ppb with a mean of 3.1 ppb -- was observed during the summer.

In the Aug. 14 accident, two 18-wheeled tankers collided on Interstate 45 two miles north of the tower. One was carrying fertilizer and pesticide, and the fumes from the resultant chemical fire reached the sensor, which recorded a spike in airborne ammonia to about 21 ppb. "If the wind was blowing the other way, we wouldn't have captured it," said Owen Gong, a graduate student in Griffin's lab and first author of the paper. "There is a bit of luck associated with this kind of field work."

A similar spike occurred a few weeks later when winds from Hurricane Hermine in the Gulf of Mexico blew emissions from industries in and around Texas City -- 40 miles south of downtown Houston -- to the tower. The next week, ammonia levels reached 27 ppb, but no source of the emissions was identified.

Griffin appreciated having access to the UH site and Lefer and Flynn's help. "Without their data to give us wind direction and other chemical information, analysis of the ammonia time series would have been difficult," he said.

He admitted that, as an environmental scientist, he lives in interesting times -- and in an interesting place. The researcher, who came to Rice from the University of New Hampshire three years ago, said few talk about airborne particles in Houston because the city is currently "in attainment with respect to the air quality standard." The team's next study will track the source and fate of other components in airborne particulate matter.

Griffin did not foresee the EPA monitoring ammonia for the sake of establishing a standard. "But because it can be such a significant precursor to particulate matter, the EPA needs to keep an eye on it," he said.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Journal Reference:

  1. L. Gong, R. Lewicki, R. J. Griffin, J. H. Flynn, B. L. Lefer, F. K. Tittel. Atmospheric ammonia measurements in Houston, TX using an external-cavity quantum cascade laser-based sensor. Atmospheric Chemistry and Physics, 2011; 11 (18): 9721 DOI: 10.5194/acp-11-9721-2011

Cite This Page:

Rice University. "Ammonia air pollution from cars and trucks worse in winter." ScienceDaily. ScienceDaily, 19 October 2011. <www.sciencedaily.com/releases/2011/10/111011132102.htm>.
Rice University. (2011, October 19). Ammonia air pollution from cars and trucks worse in winter. ScienceDaily. Retrieved December 18, 2014 from www.sciencedaily.com/releases/2011/10/111011132102.htm
Rice University. "Ammonia air pollution from cars and trucks worse in winter." ScienceDaily. www.sciencedaily.com/releases/2011/10/111011132102.htm (accessed December 18, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Thursday, December 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ivory Trade Boom Swamps Law Efforts

Ivory Trade Boom Swamps Law Efforts

Reuters - Business Video Online (Dec. 17, 2014) Demand for ivory has claimed the lives of tens of thousands of African elephants and now a conservation report says the illegal trade is overwhelming efforts to enforce the law. Amy Pollock reports. Video provided by Reuters
Powered by NewsLook.com
Indictments in West Virginia Chemical Spill Case

Indictments in West Virginia Chemical Spill Case

AP (Dec. 17, 2014) A grand jury indicted four former executives of Freedom Industries, the company at the center of the Jan. 9, 2014 chemical spill in Charleston, West Virginia. The spill contaminated the Elk River and the water supply of 300,000 people. (Dec. 17) Video provided by AP
Powered by NewsLook.com
Uphill Battle to Tackle Indonesian Shark Fishing

Uphill Battle to Tackle Indonesian Shark Fishing

AFP (Dec. 17, 2014) Sharks are hauled ashore every day at a busy market on the central Indonesian island of Lombok, the hub of a booming trade that provides a livelihood for local fishermen but is increasingly alarming environmentalists. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
France's Sauternes Wine Threatened by New Train Line

France's Sauternes Wine Threatened by New Train Line

AFP (Dec. 16, 2014) Winemakers in southwestern France's Bordeaux are concerned about a proposed high speed train line that could affect the microclimate required for the region's sweet wine. Duration: 01:06 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins