According to data released by the Navy in the
Super Hornet Draft Environmental Impact Statement (DEIS), Virginia Beach
schoolchildren will be exposed to numerous, more severe noise events that will
further threaten hearing damage.
The background of this alarming situation is as follows:
Corporations and the government annually spend millions of dollars on liability claims involving preventable hearing-related damage. According to an American Forces Information Service article, the DOD spends about $1.5 billion a year treating noise-induced hearing loss and asserts that "lower, constant noise levels can injure hearing as well -- even thru hearing protectors service members around aircraft carrier deck operations, gunnery ranges and flight lines and other loud work areas can be at risk."
Further, a Navy Health Book article dated 12 May 1994 advises that "[the Navy has determined that sound levels measured at 85 decibels or greater are considered hazardous to your hearing. Personnel exposed to hazardous noise are required to wear hearing protection.What many people do not realize is that noise-induced hearing loss can present itself gradually, over a period of years, with no physical signs or pain. Gradually, one may notice a reduction in the ability to hear speech sounds. Commonly, when a person begins to notice difficulty in understanding speech, he or she has already incurred a severe high frequency hearing loss."
To prevent hearing loss or ear damage, the Environmental Protection Agency (EPA), the National Institute of Safety and Health, the World Health Organization, the National Academy of Sciences, and other agencies have developed or adopted noise exposure criteria in order to limit such health impacts worldwide.
EPA Noise exposure criteria designed to protect the public from hearing damage considers the loudness of the noise event -- and the duration of the noise event -- to achieve a quantitative acceptable maximum daily exposure. A noise exposure limit establishes a daily exposure duration for which a particular noise level becomes hazardous if routine exposure occurs over a long period of time, i.e. 40 years.
Some individuals, however, will suffer hearing loss at lower noise levels or over shorter exposure durations.
The Navy uses average sound levels in the DEIS to develop noise zones. Average noise levels, however, are not the appropriate metric to use to assess health impacts from noise exposure. Average sound levels are typically used to estimate public annoyance and to assist communities in managing development in noise impacted areas.
The appropriate metric for assessing the potential for hearing damage is Sound Exposure Level (SEL). The SEL is a measure of the equivalent sound energy occurring over the duration of a noise event compressed into a one second interval. Regrettably, the SEL data provided in the Super Hornet DEIS is not evaluated, despite the fact that it indicates that a serious problem may exist.
Specifically, this data reveals that several schools are exposed to multiple high noise events that collectively far exceed the EPA noise exposure limits.
For example, Plaza Elementary School is projected to experience an SEL of 110.8 dB for each of ten (10) F/A-18 overflights. The EPA exposure limit for a 110.8 dB sound is 6.9 seconds per day. Therefore, after only seven aircraft events, the exposure limit is exceeded. And, since there are numerous additional loud aircraft noise events occurring at this school on a typical day, there is a substantial likelihood that this environment will contribute to long-term hearing loss in exposed children.
During periods of heavy aircraft operations, when aircraft overfly this school at intervals of 30-45 seconds, the EPA noise exposure limit could easily be exceeded during a single 15-minute recess period.
Twenty other public schools and many noise-sensitive facilities (day schools, nursery schools, church schools, etc.) are similarly exposed. Seatack Elementary School may suffer the greatest impact. Typically, this school is exposed, on a daily basis, to 44 daytime and 6 nighttime aircraft noise events at 107 116 dB SEL. The Daily Noise Dose, with these noise events ALONE, is 678 percent of the EPA exposure limit.
Similarly, the Virginia Beach Pavilion and the Lynnhaven Mall exceed EPA exposure limits by 477 and 572 percent respectively. These exposures do not take into account the scores of other daily aircraft noise event that, while less loud, are still significant, but are not included in the Navy s data.
Also according to the DEIS, the F/18-E/F produces a 117 dB (max) noise on departure at a distance of 1000 feet, yet they frequently fly below 1000 feet over many areas, including schools. The EPA exposure limit for a 117 dB (SEL) noise is only 1.8 seconds per day. Therefore, experiencing more than one such noise event per day will exceed recommended exposure criteria. (note: 117 dB [max] typically generates an SEL greater than 117 dB.)
Consequently, children attending these heavily impacted schools and residing in the surrounding communities may expect to receive the equivalent EPA lifetime (i.e. 40 year) exposure in as little as 4-5 years during the most formative years of their physical and mental (i.e. learning) development.
Further, noise of 120 dB (max) or greater exceeds the pain threshold for the average person. Many people experience pain at levels as low as 100 dB (max). Consequently, in addition to the impact on the resident population, low-flying aircraft are likely to adversely affect the Virginia Beach tourism industry. Any such painful noise experience could inhibit return visits and label Virginia Beach as a tourist spot to avoid.
The DEIS estimates that standard construction will attenuate outside noise levels by 20 dB, provided that windows are closed, and 15 dB if windows are open. Exposure to a 117 dB noise event, even under the most favorable conditions (e.g. windows closed and an interior noise level of 97 dB), will result in the noise exposure limit being exceed within a mere 3 minutes of exposure per day. If the windows are open, the noise exposure limit is a mere 53 seconds.
The Bottom Line: Even if inside a school or home in these areas, an exposed person will far exceed EPA noise exposure limits.
The DEIS, however, misleadingly asserts that; "Because it is unlikely that airport neighbors will remain outside their homes 24 hours per day for extended periods of time, there is little possibility of hearing loss below a day-night average sound level of 75 dB and this level is extremely conservative." As noted earlier, the day-night average sound level (DNL) is altogether inappropriate for evaluating the potential for hearing damage.
Seatack Elementary has a DNL of 75.4 dB, but exceeds the EPA noise exposure limit by well over 700 percent due to numerous high SEL noise events.
As a further concern, medical research has found that carbon monoxide (CO) increases the risk of hearing damage caused by noise. Under Alternative 1 the Navy projects that Oceana will produce 3794.2 tons of CO per year and acknowledges that is amount constitutes a 1703 ton (223%) increase over 2000.
While the Navy provided some SEL data as requested by CCAJN in its Scoping Comments, the data was incomplete. Importantly, the Navy failed to provide any substantial assessment of this data. The Navy must better inform the public as to how short-duration, high noise events contribute to potential hearing loss.
CCAJN is providing this good-faith analysis (using Navy data and EPA noise exposure criteria) in the absence of a credible Sound Equivalent Level (SEL) Analysis performed by the Navy and included in the DEIS. CCAJN again calls on the Navy to provide such an analysis in the Final EIS, to include a map of EPA noise exposure contours overlaid on a map of the cities of Virginia Beach and Chesapeake.
Elected representatives of Virginia Beach and Chesapeake should insist that it do so.
Representative EPA Noise Exposure Criteria
dB Noise Level EPA
Noise Exposure Limit
The Noise Exposure criteria for a particular noise level/exposure limit combination is equivalent to any other noise level and associated exposure limit. For example, a three minutes exposure to a 97 dB noise is equivalent to a 24-hour exposure to a 70 dB noise.
To determine a daily exposure for an individual exposed to noises at several loudness levels the fractional (percentage) exposures at each of the various noise levels must be added. For example, from the chart, a one and one-half minute exposure at 97 dB is one-half (50 percent) of the acceptable daily exposure that would be received from a 3-minute exposure at this particular noise intensity. Likewise, a 12-hour exposure at 70 dB is also one-half (50 percent) of the acceptable daily exposure that would be received from a 24-hour exposure at this lower noise intensity. Together, the two 50 percent exposures achieve the 100 percent of the EPA acceptable daily exposure.
Similarly, several noise level/exposure duration events can be added to achieve a percentage figure that relates to the EPA s daily acceptable exposure limit. Ideally, the resulting percentage, the Daily Noise Dose, should not exceed 100 percent for safe, long-term exposures.