Breaking News
October 19, 2018 - Conceptual framework proposed to examine role of exercise in multiple sclerosis
October 19, 2018 - Near infrared spectroscopy technique for accurate evaluation of chondral injuries
October 19, 2018 - Shorter physician encounters associated with antibiotic prescribing
October 19, 2018 - In the Spotlight: Enjoying research and exploring opportunities
October 19, 2018 - Physical activity lowers cardiovascular mortality risk in frail older adults
October 19, 2018 - New imaging tool helps visualize how sound-induced vibrations travel through the ear
October 19, 2018 - Key insights into the application, production of bioactive materials
October 19, 2018 - New urea sorbent could speed up the development of wearable artificial kidney
October 19, 2018 - Intensive care patients’ muscles less able to use fats for energy
October 19, 2018 - FDA Advisory Committee Recommends Approval of Dsuvia for the Treatment of Moderate-to-Severe Acute Pain
October 19, 2018 - 48,XXXY syndrome – Genetics Home Reference
October 19, 2018 - Physical exercise improves the elimination of toxic proteins from muscles
October 19, 2018 - How a new system improved wait times for Stanford kidney transplant patients
October 19, 2018 - Nutrition has bigger positive impact on bone mass and strength than exercise
October 19, 2018 - Study finds lack of progress in media representation of nurses over last 20 years
October 19, 2018 - Many people have trouble understanding differences between OCD and OCPD
October 19, 2018 - New family planning app found to be as effective as modern methods
October 19, 2018 - Gastric Banding, Metformin Similar for Improving Glycemia
October 19, 2018 - Physiologist publishes findings on the role of the protein titin in muscle contraction
October 19, 2018 - What digital health companies need to do to succeed
October 19, 2018 - N. Carolina Sees Alarming Spike in Heart Infections Among Opioid Users
October 19, 2018 - Video monitoring of TB therapy works well in urban and rural areas
October 19, 2018 - Determining acid-neutralizing capacity for OTC antacids
October 19, 2018 - Males who spend more time taking care of kids have greater reproductive success
October 18, 2018 - Study to explore bioethics of brain organoids
October 18, 2018 - Environmental conditions may drive development of multiple sclerosis
October 18, 2018 - Genetically modifying zebrafish provides more accurate disease models
October 18, 2018 - Purdue Pharma, Eisai announce positive topline results from Phase 3 study of lemborexant
October 18, 2018 - 5 Strength-Training Mistakes to Avoid
October 18, 2018 - Immune system’s balancing act keeps bowel disease in check
October 18, 2018 - Anti-inflammatory drug effective for treating lymphedema symptoms | News Center
October 18, 2018 - Keeping Your Voice Young
October 18, 2018 - One-time universal screening recommended to tackle increase in hepatitis C
October 18, 2018 - Researchers to develop new stem cell-based strategies for treating vision disorders
October 18, 2018 - Detecting epigenetic signature may help people stay ahead of inflammatory bowel disease
October 18, 2018 - Understanding AFib: Slowing down the dancing heart
October 18, 2018 - Using NMR to Reduce Fraud
October 18, 2018 - New automated model identifies dense breast tissue in mammograms
October 18, 2018 - Mysterious polio-like illness baffles medical experts while frightening parents
October 18, 2018 - Cases of Acute Flaccid Myelitis on the rise across U.S.
October 18, 2018 - Dietary fiber reduces brain inflammation during aging
October 18, 2018 - New tool could help prioritize recovery efforts for the poorest hit by natural disasters
October 18, 2018 - Hundreds of dietary supplements shown to contain unapproved drugs
October 18, 2018 - Active Pharmaceuticals ID’d in >700 Dietary Supplements
October 18, 2018 - Cell death protein also damps inflammation
October 18, 2018 - AI pathology diagnostic tool developed using deep learning technology from Olympus
October 18, 2018 - Health Highlights: Oct. 15, 2018
October 18, 2018 - Largest study of ‘post-treatment controllers’ reveals clues about HIV remission
October 18, 2018 - Bad Blood in Silicon Valley: A conversation with John Carreyrou
October 18, 2018 - ANTRUK’s Annual Lecture sends out message on shortage of funds for antibiotic research
October 18, 2018 - NAM special publication outlines steps to ensure interoperability of health care systems
October 18, 2018 - Novel method uses just a drop of blood to monitor effect of lung cancer therapy
October 18, 2018 - New blood test could spare cancer patients from unnecessary chemotherapy
October 18, 2018 - Training young researchers to work with data volumes arising in the health sector
October 18, 2018 - New Metrohm IC method is reliable and convenient to use for zinc oxide assay
October 18, 2018 - Global AIDS, TB fight needs more money: health fund
October 18, 2018 - Understanding the forces that cause sports concussions
October 18, 2018 - Research points to new target for treating periodontitis
October 18, 2018 - New tool improves assessment of postpartum depression symptoms
October 18, 2018 - From Biopsy to Diagnosis
October 18, 2018 - Sexual harassment and assault linked to worse physical/mental health among midlife women
October 18, 2018 - Stumped by medical school? A Q&A with a learning specialist
October 18, 2018 - Report predicts life expectancy in 2040, Spain comes out on top
October 18, 2018 - Self-lubricating condoms may help raise condom usage
October 18, 2018 - Targeting immune checkpoints in microglia could reduce out-of-control neuroinflammation
October 18, 2018 - Study finds changes in antiepileptic drug metabolism during different trimesters of pregnancy
October 18, 2018 - Autonomic nervous system directly controls stem cell proliferation, study shows
October 18, 2018 - FDA Approves Talzenna (talazoparib) for gBRCAm HER2-Negative Locally Advanced or Metastatic Breast Cancer
October 18, 2018 - Sleeping Beauty technique helps identify genes responsible for NAFLD-associated liver cancer
October 18, 2018 - Many U.S. adults confused about primary care, study shows
October 18, 2018 - UC researcher focuses on light-mediated therapies to target breast cancer
October 18, 2018 - With philanthropic gifts, Stanford poised to make major advances in neurosciences | News Center
October 18, 2018 - Mice study shows antibiotics are not always necessary to cure sepsis
October 18, 2018 - Researchers discover why heart contractions are weaker in individuals with HCM
October 18, 2018 - Participation in organized sport during childhood may have long-term skeletal benefits
October 18, 2018 - Probiotic/antibiotic combination could eradicate drug-resistant bacteria
October 17, 2018 - More Socioeconomic Challenges for Hispanic Women With HIV
October 17, 2018 - 49,XXXXY syndrome – Genetics Home Reference
October 17, 2018 - Scientists uncover possible new causes of Tourette syndrome
October 17, 2018 - Girl undergoes unusual heart surgery after compassionate-use exemption | News Center
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