Subscribe to our free daily newsletters
. Earth Science News .




Subscribe to our free daily newsletters



FROTH AND BUBBLE
Is underground transit worse for your health?
by Staff Writers
Los Angeles CA (SPX) Dec 05, 2017


illustration only

According to the U.S. Census Bureau, nearly 90 percent of the 4.5 million workers in the Los Angeles area spend an average of 60 minutes each day commuting on a roadway or railway. When USC researchers from the Viterbi School of Engineering set out to study the environmental benefits of different modes of public transit in LA, they found some unexpected results: certain SoCal public transit routes that were entirely underground exposed passengers to greater concentrations of carcinogens in the air. The research was published in Aerosol and Air Quality Research on November 29, 2017.

Constantinos Sioutas, the Fred Champion Professor of Civil and Environmental Engineering, and PhD students Christopher Lovett, Farimah Shirmohammadi and Mohammad Sowlat at the USC Viterbi School of Engineering measured particulate matter along the entirety of five popular commuter routes, including major freeways I-110 and I-710, the Metro Red and Gold Lines, as well as surface streets (Wilshire and Sunset Boulevards), representing a variety of traffic and environmental conditions.

The researchers chose these particular routes as the 710 is a corridor frequented by largely diesel-fueled commercial trucks transporting cargo from the ports, and the 110, the country's oldest freeway, which allows only non-commercial vehicles along much of its length. The surface streets had a much smaller number of commercial trucks. The Gold Line is above ground light rail, which contrasts with the Red Line, which is older and travels entirely underground.

According to a recent report published in the Lancet, air pollution is one of the great killers of our age. Polluted air was responsible in 2015 for approximately 6.5 million deaths worldwide. Particulate matter is considered to be one of the most toxic forms of air pollution.

Because of its small size, fine particulate matter less than 2.5 micrometers in diameter (the focus of this study) is able to penetrate deep within the lungs and enter the bloodstream, causing adverse health effects. Two major compounds found in airborne particulate are polycyclic aromatic hydrocarbons (PAHs), caused by incomplete fossil fuel combustion, and transition metals, (e.g. hexavalent chromium) resulting from railway friction and wear.

Both types of compounds include known carcinogens as well as being associated with chronic non-cancer health risks, such as cardiovascular and respiratory distress. The recent work builds on previous research by the Sioutas group in which only polycyclic aromatic hydrocarbons were analyzed along the same transport routes in LA.

The researchers collected air samples using battery-operated devices with particle sensors. On roadways, measurements were taken inside a zero-emissions test vehicle, while for railways, measurements were taken both on train platforms and inside cars, with the assumption that commuters spend approximately 25 percent of their time on the platform and 75 percent on the train. Samples were collected on either Teflon or quartz microfiber filters and analyzed to determine concentrations of polycyclic aromatic hydrocarbons and transition metals.

Using cancer potency factors obtained from the EPA and California's Office of Environmental Health Hazard Assessment (OEHHA), cancer and non-cancerous health risks were calculated based on a lifetime of exposure commuting one hour a day, five days a week, for 50 weeks a year, and assuming 30 years of employment.

Results:

Even though the electric-powered trains have lower levels of polycyclic aromatic hydrocarbons compared to freeways, and operate with mandatory closed windows and a mechanical ventilation system, the researchers found that the maximum Excess Lifetime Cancer Risk for the Red Line was ten-times higher than the acceptable threshold of one-in-a-million, set by government and health organizations like the World Health Organization (WHO) and the U.S. Environmental Protection Agency (EPA).

This was the result of high levels of airborne hexavalent chromium measured within the train cars, likely due to a buildup of dust resulting from friction on the steel tracks, as well as the lack of ventilation on the underground line. It is noted that the Red Line is the most used of the six LA Metro lines, with approximately 40 percent of the system's total annual ridership.

In contrast, despite some measurable concentration of hexavalent chromium, even inside personal automobiles, the maximum Excess Lifetime Cancer Risk for other measured routes was found to be within the safety threshold. The Metro Gold Line light rail exhibited the lowest exposure concentrations of hexavalent chromium and polycyclic aromatic hydrocarbons compared to all other modes of transportation studied.

"What we report is actually the absolute, most protective case scenario for the Red Line," Sioutas said. The Red Line does not have open windows and has a ventilation system, so this prevented even higher concentrations of carcinogens inside the train cars. "The initial premise of our study was to prove that you are better off not driving and instead taking the subway and the light rail. We proved part of the point with the light rail, but we were completely refuted insofar as the Red Line because of the chromium levels," Sioutas said.

The researchers suspect that other underground subway systems around the world may have similarly elevated risk scores. In addition, individuals who spend more time in the subway, particularly those who work there, would have a significantly higher health risk.

"The important thing is to alert the Metropolitan Transportation Authority, without necessarily creating undue panic, to the fact that the exposure levels to chromium and [other] carcinogenic metals are quite elevated, a lot more than would be recommended by, for example, the EPA or any other regulatory authority," Sioutas said.

FROTH AND BUBBLE
99 percent of ocean microplastics could be identified with dye
Warwick UK (SPX) Nov 29, 2017
The smallest microplastics in our oceans - which go largely undetected and are potentially harmful - could be more effectively identified using an innovative and inexpensive new method, developed by researchers at the University of Warwick. New research, led by Gabriel Erni-Cassola and Dr. Joseph A. Christie-Oleza from Warwick's School of Life Sciences, has established a pioneering way to ... read more

Related Links
University of Southern California
Our Polluted World and Cleaning It Up


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

FROTH AND BUBBLE
Beijing bans fireworks, evil spirits rejoice

Southern Chile iceberg splits from glacier, threatens navigation

China, Myanmar hail close ties amid Rohingya outcry

Despite Greek shelter, Yazidis struggle to integrate

FROTH AND BUBBLE
Device could reduce the carbon footprint of ethylene production

Researchers inadvertently boost surface area of nickel nanoparticles for catalysis

UCLA engineers use deep learning to reconstruct holograms and improve optical microscopy

Study shows how to get sprayed metal coatings to stick

FROTH AND BUBBLE
Why are there no sea snakes in the Atlantic?

The world needs to rethink the value of water

Scientists discover resilient 'heart' of Great Barrier Reef

Sea turtles' sad fate: from restaurant menus to plastic 'soup'

FROTH AND BUBBLE
Arctic, major fishing nations agree no fishing in Arctic, for now

Antarctic Selfie's Journey to Space via Disruption Tolerant Networking

Antarctic landscape insights keep ice loss forecasts on the radar

Operation IceBridge 2017: The Beauty of Ice

FROTH AND BUBBLE
Tokyo 2020 to feed IOC food from disaster-hit regions

Gene discovery may halt worldwide wheat epidemic

Genome of wheat ancestor sequenced

Getting a better handle on methane emissions from livestock

FROTH AND BUBBLE
Indonesia reopening Bali airport shut by volcanic ash fears

Albania sends in military rescue as heavy rains trigger huge floods

Bali volcano burns wedding dreams, threatens economy

16 dead, 100 missing as cyclone hits India, Sri Lanka

FROTH AND BUBBLE
Regional force deploys to Lesotho over security concerns

Mali justice minister resigns after activist's acquittal

Cash and history keep Europe as Africa's prime partner

China hails new Zimbabwe leader, denies role in transition

FROTH AND BUBBLE
Chimp females who leave home postpone parenthood

Long-term logging study demonstrates impacts on chimpanzees and gorillas

What grosses out a chimpanzee?

Human evolution was uneven and punctuated, suggests new research




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement