Breaking News
February 19, 2018 - Russian researchers develop new multi-layered biodegradable scaffolds
February 19, 2018 - Are ‘Vaccine Skeptics’ Responsible for Flu Deaths?
February 19, 2018 - Hidden genetic effects behind immune diseases may be missed, study suggests
February 19, 2018 - Study sheds light on biology that guides behavior across different stages of life
February 19, 2018 - Morning Break: Transgender Breast Feeding; Brazilian ‘Pro-Vaxxers’; Post-Stroke Exercise
February 19, 2018 - Meningitis vaccination strategy in Africa found to be effective, economical
February 19, 2018 - Researchers uncover how excess calcium may influence development of Parkinson’s disease
February 19, 2018 - Psoriasis drug also effective at reducing aortic inflammation
February 19, 2018 - Excess emissions can make serious contributions to air pollution, study shows
February 19, 2018 - Diabetes Drugs Differ on HF; School-Based Obesity Program Flop; Plaque Type in ACS
February 19, 2018 - Surgical infections linked to drug-resistant bugs, study suggests
February 19, 2018 - Poor awareness may hinder a child’s early dental care
February 19, 2018 - Researchers uncover Ras protein’s role in uncontrolled cancer growth
February 19, 2018 - FDA Approves Apalutamide (Erleada) to Help Curb a Tough-to-Treat Prostate Cancer
February 19, 2018 - Educational Tool Boosts Cervical Length Screening
February 19, 2018 - Spider’s web inspires removable implant that may control type 1 diabetes
February 19, 2018 - Scientists develop fluorescent probe to identify cancer stem cells
February 19, 2018 - University Hospital of Santiago de Compostela participates in large pancreatic cancer study
February 19, 2018 - New blood test shows promise to revolutionize diagnosis of tick-borne diseases
February 19, 2018 - Report: Use, Not Price, Drives State Health Costs
February 19, 2018 - Emergency services crews often unprepared for diabetic crises
February 19, 2018 - Scientists in Sweden create DNA nanowires that offer hope for treatment of diseases
February 19, 2018 - ID Break: Clean Hands, Fewer Abx; $11 Million HIV Cure?; MenB Vax for Kids
February 19, 2018 - Patient exposure to X-rays depends on how dentists are paid
February 19, 2018 - Study reveals parents’ views toward children’s tanning bed use
February 19, 2018 - Shot may help reduce risk of shingles
February 19, 2018 - FDA approves first treatment to reduce risk of NSCLC progression
February 19, 2018 - FDA Expands Approval of Imfinzi (durvalumab) to Reduce the Risk of Non-Small Cell Lung Cancer Progressing
February 19, 2018 - D.C. Week: Congress Passes Spending Bill
February 19, 2018 - Heart-muscle patches made with human cells improve heart attack recovery
February 19, 2018 - FDA Approves First Blood Test to Detect Concussions
February 19, 2018 - Survival Bump in Bladder Cancer with Keytruda
February 18, 2018 - Scientists describe the mechanism of heart regeneration in the zebrafish
February 18, 2018 - Scientists uncover the structure of microtubule motor proteins
February 18, 2018 - Light-activated cancer drugs without toxic side effects are closer to becoming reality
February 18, 2018 - Pioneering research could provide novel insight into how genomic information is read
February 18, 2018 - Pearls From: David Putrino, PhD
February 18, 2018 - Researchers uncover how cancer stem cells drive triple-negative breast cancer
February 18, 2018 - Morning Break: Anti-Anti-Vaxxers; Private Piercings Prohibited; A Case for Pelvic Massage
February 18, 2018 - Lower-dose radiation effective, safe for HPV+ head and neck cancer after induction chemo
February 18, 2018 - Specialist residential service for adults with autism opens in Swansea
February 18, 2018 - FDA Moves to Limit Loperamide Doses per Package
February 18, 2018 - Alcohol use disorder – Genetics Home Reference
February 18, 2018 - Autism might be better detected using new two-minute questionnaire
February 18, 2018 - Hand hygiene-intervention practices may reduce risk of infection among nursing home patients
February 18, 2018 - Researchers develop most sophisticated mini-livers to date
February 18, 2018 - Obamacare Helped More Young Women Get Prenatal Care: Study
February 18, 2018 - School-Based Program Fails to Dent Kids’ Obesity
February 18, 2018 - Research compares neural activity in children with and without autism spectrum disorder
February 18, 2018 - Poor fitness levels increase the risk dementia, concludes study
February 18, 2018 - Risk Score May Reveal if Kids are Victims of Ill-Treatment
February 18, 2018 - Adding Folic Acid to Corn Masa Flour May Prevent Birth Defects
February 18, 2018 - Acute treatment suppresses posttraumatic arthritis in ankle injury
February 18, 2018 - A Role for Budesonide in Autoimmune Hepatitis?
February 18, 2018 - Lupus patients exhibit altered cell proteins, a discovery with potential implications for diagnostics
February 18, 2018 - Muscle plays vital role in regulating heat loss from the hands
February 18, 2018 - High-tech brain scans can provide new way to define intelligence
February 18, 2018 - Study reveals the association between ultra-processed foods and cancer
February 18, 2018 - Prescription Opioid Use Tied to Higher Pneumonia Risk
February 18, 2018 - A non-invasive method to detect Alzheimer’s disease
February 18, 2018 - Deletion of specific enzyme leads to improvement in memory and cognitive functions
February 18, 2018 - Amyloid protein may be transmitted through neurosurgical instruments, study suggests
February 18, 2018 - Electric brain signals of males and females show differences
February 18, 2018 - American Heart Association commends McDonald’s for offering healthier menu in kids’ meals
February 18, 2018 - Parents Find Kids’ Weight Report Cards Hard to Swallow
February 18, 2018 - Does a Financial Conflict of Interest Ever Expire?
February 18, 2018 - Exercise can improve Alzheimer’s symptoms
February 18, 2018 - Scientists develop green chemistry method to improve pharmaceutical manufacturing efficiency
February 17, 2018 - ‘A Time Clock to a Tissue Clock’ for Acute Stroke Care
February 17, 2018 - Cancer Care Gets Personal | NIH News in Health
February 17, 2018 - Do more youth use or do youth use more?
February 17, 2018 - Eating faster linked to obesity
February 17, 2018 - Who’s Still Smoking? ACS Report Highlights Most Vulnerable Adults
February 17, 2018 - Study of smoking and genetics illuminates complexities of blood pressure
February 17, 2018 - Study reveals new link between bone cells and blood glucose level
February 17, 2018 - Children with reading challenges may have lower than expected binocular vision test results
February 17, 2018 - Mass Shootings Trigger Change for Emergency Medicine
February 17, 2018 - ECMO helps revive woman thought to be drowned
February 17, 2018 - Learning stress-reducing techniques may benefit people with epilepsy
February 17, 2018 - Shedding Pounds Before Weight-Loss Surgery a Smart Move
Underground transit routes expose passengers to greater concentrations of carcinogens, study finds

Underground transit routes expose passengers to greater concentrations of carcinogens, study finds

image_pdfDownload PDFimage_print

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.​

Tagged with:

About author

Related Articles