Posts Tagged ‘noise’

The Quiet Car

Tuesday, November 20th, 2012

by Mary Ellen Eagan

Those of you who like the Acela Quiet Car will appreciate this piece posted in the New York Times Sunday Review section this weekend.  I’ve had similar experiences – in fact, during my last trip on the Acela, and I was compelled to post on facebook (quietly typing) that a fight was about to break out on the Quiet Car.

Is it just the last refuge that those of us seeking quiet are holding on to so desperately?  Is it because we feel empowered because of the signs?  And most importantly, how do we get a “quiet car” on airplanes??

Quiet car sign

Quiet car sign

The Cocktail Party Effect

Wednesday, April 25th, 2012

by Mary Ellen Eagan

First, I must admit that it was the photo that caught my eye – we don’t have cable at home, and it’s killing me that I’m missing Mad Men Season 5.

What cocktail parties teach us

Today’s Wall Street Journal has an article on “the cocktail party effect” which talks about the role of background noise on our ability to focus, especially in settings such as cocktail parties.  Apparently when we focus on a single conversation, our auditory cortex boosts the signal of that conversation to prioritize what’s most important.  Pretty cool.

The focus of the article really, though, is about attention, and how the findings of the cocktail study demonstrate why people aren’t very good at multitasking:  namely, our brains are wired for “selective attention” and can focus on only one thing at a time.   This has important implications for distracted driving, walking, and other forms of multitasking.   And yet, our kids seem to be pretty good at it.

BTW, a related condition is “selective hearing” – that’s when you ask your mate to take out the trash (or any other “yes, dear” chore) and it doesn’t happen.  Hint:  ask for a “read-back” (works especially well with pilots).

Got PBN?

Wednesday, March 28th, 2012

by Mary Ellen Eagan

Apologies for the somewhat belated post, but here’s a quick recap of the recent UC Davis Noise and Air Quality Symposium: Navigating NextGen, held March 4-6 in Palm Springs, CA.

The focus of much of the discussion at this year’s symposium was implementation of the FAA’s NextGen Program, the early phases of which are now being rolled out across the country.  This blog has discussed NextGen issues before, but I think this was the first conference I’ve attended that attendees were uniformly focused on finding ways to make implementation a success.

The symposium keynote was delivered by Dennis Roberts of the FAA’s ATO. Dennis is responsible for managing FAA’s Optimization of Airspace and Procedures in the Metroplex (OAPM) “metroplex” projects, a systematic, integrated, and accelerated program to implement satellite based navigation in the aviation system.   HMMH is involved in several of the metroplex projects, including the Houston Metroplex, which is on the President’s Federal Infrastructure Dashboard, which was initiated to monitor the pace of DOT efforts to accelerate major infrastructure projects by improving permitting and environmental review processes, and to improve the accountability, transparency, and efficiency of Federal actions. 

Other sessions focused on providing an overview of NextGen technologies and Performance Based Navigation (PBN) terminology, as well as airport experiences implementing and collaborating with FAA on the implementation of procedures at their airports.  The takeaway message from the entire symposium is that there is an urgent need for airports to get involved with NextGen airspace planning – airports understand local issues and provide a critical link between communities and the FAA.  Many airports have also spent years developing noise abatement programs and must be at the table to ensure that airspace planners understand both the spirit and substance of noise abatement.  As active participants in several of these projects, we at HMMH believe that this collaborative approach will be critical to early success of NextGen.

Presentations for the symposium can be found here (click on the presenter’s name).  Next year’s symposium will be held in Orange County, CA.  Please let me know if you have suggestions for topics for discussion.

Standing on the shoulders of giants

Tuesday, December 13th, 2011

by Nick Miller

Ted Schultz was one of my early mentors when I began my career in noise and acoustics.  When I first joined Bolt Beranek and Newman Inc. he was consulting to HUD, providing technical background for its noise abatement standards.  Throughout that impressive and detailed work, he considered annoyance as one of the important reactions to noise and, I believe, collected and analyzed social surveys relating annoyance to sound levels.  As a further outcome, in 1978, Ted published in the Journal of the Acoustical Society of America, his “Synthesis of social surveys on noise annoyance,” (see also my blog of April 2010 ).  This article provided in its Figure 6 a curve giving percent of people highly annoyed as a function of noise exposure in terms of day-night average sound level.  This curve became associated with much of present federal policy for determining noise “impact” and is commonly called the Schultz curve.

For the past few years, there has been general concern that this curve may no longer accurately represent how people respond to aircraft noise.  Because Federal Aviation Administration noise policy is required by legislation to use a system of noise measurement that has “… a highly reliable relationship between projected noise exposure and surveyed reactions of individuals to noise….” (49 U.S.C Section 47502) it is important that the relationship of annoyance and noise exposure be reliable and reflects current conditions.

The Airport Cooperative Research Program is sponsoring research to design a new national survey of annoyance reactions and sleep disturbance caused by aircraft noise.  One objective is to develop an up-to-date, unbiased estimate of the annoyance / noise exposure relationship for US airports and surrounding communities – potentially an update of the Schultz curve.   We were fortunate enough to put together a team and a winning proposal to conduct this research.  Now, I must say that I knew Ted Schultz, Ted Schultz was a friend of mine, and I’m certainly no Ted Schultz, but I am nevertheless honored to be leading this team in work that is a direct follow-on to Ted’s impressive  accomplishment.

A Better Way to Compare Aircraft Noise and Emissions?

Wednesday, April 6th, 2011

by Nick Miller

The World Health Organization (WHO) has recently published “Burden of disease from environmental noise, Quantification of healthy life years lost in Europe.” The title sparked my interest because there is an on-going effort in the U.S. to quantify and compare the relative adverse effects on society caused by aviation noise and aviation produced air pollutants. For the primary air pollutants, current U.S. work translates benefits of reductions to such things as reductions in premature mortality and in chronic bronchitis, to which dollar benefits are assigned. For noise, the Noise Depreciation Index (NDI) reveals how many dollars in housing prices are gained by reducing noise. 

I’ve always been troubled by this comparison of dollars of house price saved versus dollars of lives saved –not because I doubt either the calculations or assigning dollars to a life, which is standard in many cost benefit analyses. But my opinion, shared I think by many who deal with community reactions to aircraft noise, is that house prices really don’t reflect the adverse noise effects of living near a busy airport. For one thing, realtors and sellers go out of their way to down-play the aircraft noise issue.

Well, whether or not we want to pursue that debate, here come the Europeans and WHO, with “disability-adjusted life-years” (DALYs) as a method for quantifying any environmental health effect, and a report specifically addressing noise. Though my hopes for enlightenment about aircraft noise were immediately dashed when I learned that this report deals almost exclusively with the effects of road traffic noise, the DALY method may eventually have some use for comparison of aviation noise and emissions effects.

So how do we compute DALYs? Basically it’s the sum of years of life lost (e.g., premature mortality) and years lived with disability, or years of healthy life lost (e.g., suffering chronic bronchitis). The noise produced disabilities the WHO report examines are cardiovascular disease, cognitive impairment in children, sleep disturbance, tinnitus and annoyance. These are all adverse health effects consistent with the WHO definition of health as being “a state of complete physical, mental and social well-being.”

Computation of DALYs requires knowledge of the number of people exposed to each level of noise, a dose-response relationship that gives percent of people affected at each level, the “disability weight,” DW, assigned to the effect (DW equals zero means no health effect, DW equals one, you die), and the number of years of living with the disability or years of life lost. Obviously, many assumptions are required, but I like the way the large number of assembled subject area experts synthesized their knowledge and the research literature results to quantify each variable and calculate the DALYs for each health effect. 

What most struck me, was the number of experts (41 are listed) who participated in developing the report. In contrast, current U.S. efforts have required that many people come up to speed on the effects of aircraft noise on people, working with an additional very few who had actually worked in the field of aircraft noise effects. (Three cheers to the FAA for bringing in experts from outside the U.S. to assist with development of the Aviation Noise Impacts Roadmap.) To be clear, those who had to learn, were already experts, many in acoustics, just not in aviation noise and its effects.

In some ways, how sad. In the 1970’s the U.S. lead the world in developing the knowledge needed to formulate a national policy on noise and noise control. But those efforts all stopped short in the early 1980’s. Hence, most of those with expertise have retired and no new blood added for these three decades.

Now that we are concerned about how we can expand the U.S. air transport system, change airspace use, add runways, and increase the use of under-utilized airports, recognition has come that we better understand what the noise and air quality effects will be on society. Let’s hope that we can develop enough understanding to provide the aviation decision-makers with the information they need for science based noise and emissions policy. Perhaps a bit more of looking to research results gathered outside the U.S. would benefit our efforts.