Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

People near freeways are exposed to 30 times the concentration of dangerous particles

18.10.2002


People who live, work or travel within 165 feet downwind of a major freeway or busy intersection are exposed to potentially hazardous particle concentrations up to 30 times greater than normal background concentrations found at a greater distance, according to two recently published UCLA studies.



The studies -- published in the Journal of the Air and Waste Management Association and in Atmospheric Environment -- show that proximity to a major freeway or highway dramatically increases exposure to "ultrafine" particles (tiny particles less than 0.1 micrometers in diameter), which are linked to neurological changes, mild pulmonary inflammation and cardiovascular problems. The U.S. Environmental Protection Agency (EPA) currently regulates particles less than 2.5 micrometers in diameter, and ultrafines represent the very smallest particles inhaled by the public.

Traffic-related air pollution is of great concern to Los Angeles, which has the most severe particle air-quality problem in the United States. The Los Angeles Basin is home to more than 15 million residents and 10 million vehicles contributing to its daily traffic. Motor vehicle emissions represent the most significant source of ultrafine particles. Moreover, recent toxicological studies have shown that ultrafine particles are more toxic than larger particles, potentially leading to increased mortality and illness with increased exposure to particulate matter.


"We believe this is the first study conducted in the United States that provides a detailed spatial profile of ultrafine particles near freeways," said William C. Hinds, a professor of environmental health sciences in the UCLA School of Public Health, who co-authored the studies with Yifang Zhu, a doctoral candidate in the School of Public Health.

The studies, conducted through the Southern California Particle Center and Supersite (SCPCS), assessed the size-distribution and concentration of the tiny ultrafine particles near major freeways. The first study focused on Interstate 405, one of the nation’s busiest freeways, with 93 percent of the traffic composed of gasoline-powered cars. The second study looked at the 710 freeway, which has more than 25 percent of its traffic derived from heavy-duty diesel trucks.

By measuring the number of particles and their size at varying distances from the 405 and 710, Hinds and Zhu concluded that the number of ultrafine particles downwind near both freeways was approximately 25 to 30 times greater than the number upwind. The drop in the number of ultrafine particles occurred rapidly with increasing distance from the freeway, falling to 30 percent of peak concentration at 330 feet. The rapid decrease and dilution in particle concentration was due to several factors, including atmospheric dispersion, coagulation, and wind direction and speed.

Both Hinds and Zhu concur that better understanding of the size and concentration of ultrafine particles is vital, particularly in a city with 85 million vehicle-miles traveled on its freeways on an average day.

"The objectives of the study include providing scientists with a way to predict exposure concentrations to ultrafine particles near freeways in order to facilitate health studies and provide data for the development of an air-quality standard for ultrafine particles," Zhu said.

The studies also examined the concentrations of carbon monoxide (CO), black carbon (BC) and particle mass. Both CO and BC concentrations are closely related to vehicle emissions. Like ultrafines, CO and BC concentrations decreased significantly (70 percent to 80 percent) within the first 330 feet downwind of the freeway. This confirms the notion that vehicular exhaust is a major source of these pollutants near a major roadway.

The SCPCS -- housed in the School of Public Health and the Institute of the Environment at UCLA, and funded by the EPA’s Science To Achieve Results (STAR) program and California Air Resources Board -- brings together outstanding scientists from leading universities throughout the nation to create dynamic new ways of investigating the health effects of particulate matter and to secure the protection of public health by better informing policy.

Wendy Hunter | EurekAlert!
Further information:
http://www.scpcs.ucla.edu

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>