Breaking News
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 - Targeting immune checkpoints in microglia could reduce out-of-control neuroinflammation
October 18, 2018 - FDA Approves Talzenna (talazoparib) for gBRCAm HER2-Negative Locally Advanced or Metastatic Breast 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
October 17, 2018 - Health Issues That Are Sometimes Mistaken for Gluten Sensitivity
October 17, 2018 - Elective induction of labor at 39 weeks may be beneficial option for women and their babies
October 17, 2018 - New smart watch algorithms can accurately monitor wearers’ sleep patterns
October 17, 2018 - Researchers demonstrate epigenetic memory transmission via sperm
October 17, 2018 - FDA, DHS announce memorandum of agreement to address cybersecurity in medical devices
October 17, 2018 - Health Tip: Know the Risks of Chicken Pox
October 17, 2018 - Immunotherapy effective against hereditary melanoma
October 17, 2018 - Researchers reveal new mechanism for how animal cells stay intact | News Center
October 17, 2018 - Alzheimer's Goes Under the Cryo-Electron Microscope
October 17, 2018 - Medicare for all? CMS chief warns program has enough problems already
October 17, 2018 - Metrohm Raman introduces Mira P handheld Raman system
October 17, 2018 - Expanding the knowledge about hippocampus to better understand cognitive deficits in MS
October 17, 2018 - Study of Nigerian breast cancer patients reveals prevalence of aggressive molecular features
October 17, 2018 - Many healthy children may have metabolic risk factors, finds study
October 17, 2018 - A new antibiotic could be a better, faster treatment for tuberculosis
October 17, 2018 - “I will not become a Robot Doctor”: A medical student vows to practice compassion
October 17, 2018 - Study findings may explain sporadic outbreaks of C. difficile infections in hospitals
October 17, 2018 - Purdue researchers develop new chemical process to find better drug ‘fits’ for patients
October 17, 2018 - Yale researchers develop way to attack RNA with small-molecule drugs
October 17, 2018 - New pragmatic study launched to understand the effectiveness of new type 2 diabetes drug
October 17, 2018 - Alnylam Announces Plan to Initiate Rolling Submission of a New Drug Application and Pursue Full Approval for Givosiran
October 17, 2018 - Nine cases of polio-like illness suspected in children in illinois
October 17, 2018 - Eisai enters into agreement with Eurofarma for development and sales of lorcaserin in 17 countries
October 17, 2018 - Patients once thought incurable can benefit from high-dose radiation therapy
October 17, 2018 - Researchers awarded grant to advance testing of experimental heroin vaccine
October 17, 2018 - Researchers examine SSRI use during pregnancy and major gestational malformations
October 17, 2018 - FDA grants Rare Pediatric Disease Designation for Immusoft’s Iduronicrin genleukocel-T
October 17, 2018 - Reliable Respiratory announces acquisition of Attleboro Area Medical Equipment
October 17, 2018 - Study reveals link between childhood abuse and higher arthritis risk in adulthood
October 17, 2018 - Research shows people over 65 are not performing enough physical activity
October 17, 2018 - FDA Approves Liletta (levonorgestrel-releasing intrauterine system) 52 mg to Prevent Pregnancy for up to Five Years
October 17, 2018 - Weight gain after smoking cessation linked to increased short-term diabetes risk
October 17, 2018 - Researchers find opportunity to control salt-sensitive hypertension without exercising
October 17, 2018 - Women not warned about cancer associated with breast implants
October 17, 2018 - Metrohm offers robust handheld Raman analyzer for Defense and Security
October 17, 2018 - Modeling Non-Numerical Data in Systems Biology
October 17, 2018 - Research aims to address health disparities in African-American men
October 17, 2018 - Human and cattle decoys trap outdoor-biting mosquitoes in malaria endemic regions
October 17, 2018 - High Circulating Prolactin Level Inversely Linked to T2DM Risk
October 17, 2018 - Study finds gene variant predisposes people to both Type 2 diabetes and low body weight
October 17, 2018 - Metrohm software products make it easy to comply with ALOCA and ALCOA+ guidelines
October 17, 2018 - Network of doctors identify the cause of 31 new conditions
October 17, 2018 - Notable improvement in brain cancer survival among younger patients but not much for elderly
October 17, 2018 - Scientists shed light on roles of transcription factors, TP63 and SOX2, in squamous cell carcinoma
October 17, 2018 - Costs of Medicare Diabetes Prevention Program may be higher than expected reimbursement
October 17, 2018 - Misuse of prescription opioids or benzodiazepines associated with suicidal thoughts
October 17, 2018 - New research seeks to address sex disparities in women’s health
October 17, 2018 - C-Section Rates Have Nearly Doubled Since 2000: Study
October 17, 2018 - Talking to Your Kids About STDs
October 17, 2018 - New classification of periodontal and peri-implant diseases and conditions
October 17, 2018 - Herbert D. Kleber, Pioneer in Addiction Treatment, Dies at 84
October 17, 2018 - Health effects of smoke-filled atmosphere
October 17, 2018 - Down syndrome may hold important clues to onset of Alzheimer’s disease
October 17, 2018 - A special report on US’ aging societies
October 17, 2018 - Birth mode may have acute effects on neurodevelopment, study suggests
New study shows why winter air pollution levels have remained high in the United States

New study shows why winter air pollution levels have remained high in the United States

image_pdfDownload PDFimage_print

The air in the United States is much cleaner than even a decade ago. But those improvements have come mainly in summer, the season that used to be the poster child for haze-containing particles that cause asthma, lung cancer and other illnesses.

A new study led by the University of Washington shows why winter air pollution levels have remained high, despite overall lower levels of harmful emissions from power plants and vehicles throughout the year.

“In the past 10 years or so, the summer air pollution levels have decreased rapidly, whereas the winter air pollution levels have not. Air quality in summer is now almost the same as in winter in the eastern U.S.,” said corresponding author Viral Shah, who did the work as part of his UW doctorate in atmospheric sciences. “We have pinpointed the chemical processes that explain the seasonal difference in response to emissions reductions.”

The study, published the week of July 23 in the Proceedings of the National Academy of Sciences, shows that the particles follow different pathways in the winter.

Results came from analyzing observations collected during the 2015 Wintertime Investigation of Transport, Emissions and Reactivity (WINTER) campaign. During that UW-led effort, researchers spent six weeks in winter flying through pollution plumes over New York City, Baltimore, Cincinnati, Columbus, Pittsburgh, Washington, D.C., and along the coal-fired power plants of the Ohio River Valley.

The study was funded by the National Science Foundation, with in-kind support from NASA and the National Oceanic and Atmospheric Administration.

Particles that form smog come in different flavors. Two important ones are sulfates, from sulfur dioxide emitted mainly by coal-fired power plants, and nitrates, created from nitrogen oxides known collectively as NOx. Air-quality regulations have lowered sulfur dioxide in the U.S. by 68 percent between 2007 and 2015, and NOx by about a third during that time.

Summertime levels of particulates -; when the two flavors of oxides clump up into watery packets of nitrates and sulfates that create beautiful sunsets but harm human health -; have dropped in the eastern U.S. by about a third during that time. But the winter concentrations of particulates have decreased by only half as much, for reasons that had been unclear.

“The air quality models that we use to understand the origin of air pollution perform quite well in summer, but have some issues in the wintertime. Before this study, we could not reproduce the observed particulate composition in winter,” said Lyatt Jaeglé, who was second author on the paper and co-principal investigator of the field campaign. “We now have a better tool to look at what is the best strategy to improve wintertime air quality on regional scales in the eastern U.S., and potentially other places, like Europe and Asia.”

In the summer, some of the emitted NOx and sulfur dioxide remains in the gas phase and gets zapped by sunlight or deposited on land, and the rest forms particulates in the form of nitrates and sulfates. As the primary ingredients drop, so do the levels of particulates.

But the new analysis shows that the chemistry of wintertime air follows a more complex path. With less sunlight and colder temperatures, more of the chemistry happens in the liquid phase, on the surfaces of existing particulates or liquid and ice clouds. In that phase, as the primary ingredients drop, the efficiency of converting sulfur dioxide to sulfate rises, because more oxidants are available. And as sulfate goes down, the particulates become less acidic, making NOx convert more easily to nitrates.

So, even though air quality regulations have reduced both types of primary emissions, the total amount of particulates that harm human health has dropped more slowly.

“It’s not that the reductions aren’t working. It’s just that the reductions have a cancelling effect, and the cancelling effect has a set strength,” said Shah, who is now a postdoctoral researcher at Harvard University. “We need to make further reductions. Once the reductions become larger than the cancelling effect, then winter will start behaving more like summer.”

The study predicts that unless emissions reductions outpace current forecasts, air quality in winter will continue to improve only gradually until at least 2023. At this rate it would be several years before emissions reach levels when wintertime pollution starts to drop more quickly.

“This paper shows that understanding the underlying atmospheric chemistry that converts primary pollutants into fine particulate matter is critical for calibrating our expectations about what emissions reductions will accomplish, and therefore for how to optimize future emissions reductions to continue getting the ‘biggest bang for the buck’ in terms of reducing fine particulate matter concentrations,” said third author Joel Thornton, who was the principal investigator on the field campaign.

The findings suggest that more emissions reductions, of both sulfur and nitrogen oxides, will be needed to improve wintertime air quality in the Eastern U.S. and other cold climates.

“This research helps explain why emissions controls to reduce air pollution substances, such as sulfate and nitrate, have not been as successful as expected in the eastern U.S. in winter,” said Sylvia Edgerton, program director in the NSF’s Division of Atmospheric and Geospace Sciences, which funded the research. “The WINTER field campaign produced a unique set of winter observations. They demonstrate that chemical feedbacks during winter months counteract expected reductions in air pollution due to reduced emissions.”​

Source:

http://www.washington.edu/news/2018/07/23/study-shows-why-eastern-u-s-air-pollution-levels-are-more-stagnant-in-winter/

Tagged with:

About author

Related Articles