In addition, the committee examined research based on large population groups to find how changes in ozone air concentration could affect mortality, specifically to determine the existence of a threshold -- a concentration of ozone below which exposure poses no risk of death. The committee concluded that if a threshold exists, it is probably at a concentration below the current public health standard. As people have individual susceptibilities to ozone exposure, not everyone may experience an altered risk of death if ozone air concentration also changes. Further research should explore how personal thresholds may vary and the extent to which they depend on a person's frailty, the committee said.
The research on short-term exposure does not account for all ozone-related mortality, and the estimated risk of death may be greater than if based solely on these studies, the committee noted. To better understand all the possible connections between ozone and mortality, future research should address whether exposure for more than 24 hours and long-term exposure -- weeks to years -- are associated with mortality, including how ozone exposure could impact life expectancy. For example, deaths related to short-term exposure may not occur until several days afterward or may be associated with multiple short-term exposures.
Additionally, EPA should monitor ozone during the winter months when it is low and in communities with warmer and cooler winters to better understand seasonal and regional differences in risk. More research could also look at how other pollutants, such as airborne particulate matter, may affect ozone and mortality risk.
EPA, like other federal agencies, is required to carry out a cost-benefit analysis on mitigation actions that cost more than $100 million per year. EPA recently used the results of population studies to estimate the number of premature deaths that would be avoided by expected ozone reductions for different policy choices, and then assigned a monetary value to the avoided deaths by using the value of a statistical life (VSL).
The VSL is derived from studies of adults who indicate the "price" that they would be willing to pay -- i.e. what benefits or conveniences someone would be willing to forgo -- to change their risk of death in a given period by a small amount. The monetary value of the improved health outcome is based on the value the group places on receiving the health benefit; it is not the value selected by policymakers or experts.
EPA applies the VSL to all lives saved regardless of the age or health status. For instance, a person who is 80 years old in poor health is estimated to have the same VSL as a healthy 2-year-old. To determine if an approach that accounts for differences in remaining life expectancy could be supported scientifically, EPA asked the committee to examine the value of extending life. For example, EPA could calculate VSL to estimate the value of remaining life, so a 2-year-old would have a higher VSL than an 80-year-old. It is plausible that people with shorter remaining life expectancy would be willing to devote fewer resources to reducing their risk of premature death than those with longer remaining life expectancy. In contrast, if the condition causing the shortened life expectancy could be improved and an acceptable quality of life can be preserved or restored, people may put a high value on extending life, even if they have other health impairments or are quite elderly.
The committee concluded that EPA should not adjust the VSL because current evidence is not sufficient to determine how the value might change according to differences in remaining life expectancy and health status. However, the committee did not reject the idea that such adjustments may be appropriate in the future. To move toward determining a value of remaining life, alternative approaches should be explored in sensitivity analyses, and further research should be conducted to answer the questions raised about the validity of EPA's current approach.
The study was sponsored by the U.S. Environmental Protection Agency. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies. They are private, nonprofit institutions that provide science, technology, and health policy advice under a congressional charter. The Research Council is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering. A committee roster follows.
Jennifer Walsh | EurekAlert!
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses