Featured Research

from universities, journals, and other organizations

Air Pollution From Freeway Extends One And A Half Miles Away

Date:
June 28, 2009
Source:
University of California, Los Angeles
Summary:
Scientists have found that during the hours before sunrise, freeway air pollution extends much further than previously thought. Pollutants were found 1.5 miles from I-10 in California during early morning hours.

Traffic jam in Los Angeles. Researchers have found that during the hours before sunrise, freeway air pollution extends much further than previously thought.
Credit: iStockphoto

Environmental health researchersfrom UCLA, the University of Southern California and the California Air Resources Board have found that during the hours before sunrise, freeway air pollution extends much further than previously thought.

Air pollutants from Interstate 10in Santa Monica extend as far as 2,500 meters —more than 1.5 miles —downwind, based on recent measurements from a research team headed by Dr. Arthur Winer, a professor of environmental health sciencesat the UCLA School of Public Health. This distanceis10 times greater thanpreviously measured daytime pollutant impacts from roadways and has significant exposure implications, since most people are in their homes during the hours before sunrise and outdoor pollutants penetrate into indoor environments.

The study was published last monthin the journal Atmospheric Environment, with Dr. Shishan Hu, a postdoctoralscholar at the UCLA School of Public Health,as lead author.

"To measure the pollution levels, we equipped an electric vehicle with no emissions of its own with fast-response instruments for gaseous and particulate air pollutants, a GPS and video monitor, and instruments to measure temperature and winds," Winer said. "In both winter and summer of 2008, we drove toward and away from Interstate 10 on a route perpendicular to the freeway in Santa Monica between the hours of 4 a.m. and 7 a.m."

A second striking finding of the study was that although traffic volumes are lower in the pre-sunrise hours, the air pollution concentrations measured by the team were higher than even those during daytime traffic congestion peaks. Concentrations are higher before sunrise even though emissions are lower because of the unique weather conditions. In the pre-sunrise hours, wind speeds are generally very low, and while the wind direction is somewhat variable, the predominant direction is from the northeast in the winter months and the northwest in the summer months.

This means thatareas south ofInterstate 10 are generally downwind in the pre-sunrise hours and areas north of the freeway are generally upwind; this is consistent with the observation that vehicle-related pollutants are found much further from the freeway on the south side in the pre-sunrise hours, compared with the north side.

"Our research shows that under the low wind speeds and shallow temperature inversions during the early morning, before sunrise, air pollution from freeways is trapped near the surface, limiting dilution and creating a zone of influence many times greater than during the day," said Dr. Suzanne Paulson, a professor in the UCLA Department ofAtmospheric and Oceanic Sciences and a co-principal investigator of the study. "These meteorological conditions are very common in the hours before sunrise."

In comparing the winter and summer early mornings, researchersfound much higher levels of air pollution in the winter.

"This is because the sun rises later in the winter, so the early morning period captures more of the early morning rush hour," Paulsen said.

"Our findings confirm previous work showing peak levels of ultrafine particles (UFP) immediately adjacent to the freeway, but we found high concentrations persisted for up to 1.5 miles downwind of the freeway during the pre-sunrise hours," said Dr. Scott Fruin of the USC Keck School of Medicine. "Elevated UFP concentrations also extended up to 600 meters upwind of the freeway, another strong difference from daytime observations, which typically show little or no vehicle-related pollution directly upwind from freeways."

In the present study, other pollutants, including nitric oxide and particle-bound polycyclic aromatic hydrocarbons, also extended far from the freeway during the pre-sunrise hours.

Other members of the research team included Dr. Kathleen Kozawa and Steve Mara of the California Air Resources Board, which sponsored the study.

"The study raises more questions about the significant health outcomes caused or exacerbated by freeway traffic," Winer said.

Numerous epidemiologic studies have already shown that traffic-related pollution is linked to increased risk of asthma, respiratory illness, cardiovascular disease and premature mortality.

The researchers recommend thatresidents living near freeways should consider keeping their windows closed at night and minimize outdoor exercise near major roadways in the hours before sunrise.


Story Source:

The above story is based on materials provided by University of California, Los Angeles. Note: Materials may be edited for content and length.


Cite This Page:

University of California, Los Angeles. "Air Pollution From Freeway Extends One And A Half Miles Away." ScienceDaily. ScienceDaily, 28 June 2009. <www.sciencedaily.com/releases/2009/06/090618172409.htm>.
University of California, Los Angeles. (2009, June 28). Air Pollution From Freeway Extends One And A Half Miles Away. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2009/06/090618172409.htm
University of California, Los Angeles. "Air Pollution From Freeway Extends One And A Half Miles Away." ScienceDaily. www.sciencedaily.com/releases/2009/06/090618172409.htm (accessed September 17, 2014).

Share This



More Matter & Energy News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

Newsy (Sep. 16, 2014) MIT developed a robot modeled after a cheetah. It can run up to speeds of 10 mph, though researchers estimate it will eventually reach 30 mph. Video provided by Newsy
Powered by NewsLook.com
Manufacturer Prints 3-D Car In Record Time

Manufacturer Prints 3-D Car In Record Time

Newsy (Sep. 15, 2014) Automobile manufacturer Local Motors created a drivable electric car using a 3-D printer. Printing the body only took 44 hours. Video provided by Newsy
Powered by NewsLook.com
Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Reuters - US Online Video (Sep. 15, 2014) New York officials unveil subway tunnels that were refurbished after Superstorm Sandy. Nathan Frandino reports. Video provided by Reuters
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:
from the past week

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