Page 27 - Winter 2009

HOT TOPICS IN NOISE
Nancy S. Timmerman
25 Upton Street Boston, MA 02118
“...the subject is noise, a term which needs no explanation.”
Scientists often discuss the newest riers along the road (thereby blocking
things that they are doing so that
others know what’s going on. The subject of this article is noise, a term which, for most people, needs no explanation.
Community noise and vibration from transportation
Noise from transportation affects nearly everyone (Figs. 1–3) and noise levels are regulated by Federal laws. Transportation noise that enters a home can be reduced by home improvements.
The Federal Aviation Administration (FAA) oversees airport noise studies. Their NextGEN program is working on making quieter aircraft. Aircraft noise exposure is still com- puted using the Integrated Noise Model (INM), and revision 7.0b was recently released. The FAA is working toward hav- ing one modeling program to cover both air quality and noise (AEDT), which should be available in 2010.
For highways, the state highway departments and turn- pike authorities are responsible for addressing community noise. Two ways to reduce this noise source are to use bar-
Fig. 2. Transportation: Road/Truck.
the view), or, in warm climates, to use porous pavements. A recent medical study in Sweden has related high blood pressure to highway noise.
Sustainable energy—wind turbines
Sustainable energy is all the rage with governments at all levels in the US. What is usually meant is not coal, oil, or natural gas (fossil fuels), but rather solar panels, wind tur- bines, and geothermal wells. Unfortunately, energy pro- duced from these devices is quite expensive and the gov- ernment has subsidized them to encourage their develop- ment. Solar panels and wind turbines are thought to be “environmentally friendly.”
It has been known for some time that neighbors of wind turbines sometimes complain about their noise (Fig. 4). This is particularly true when they are placed in rural areas. Background sound levels in these areas are often low, and nighttime levels of 35 dBA have caused complaints. The tur- bines produce a “swishing” sound, which is very annoying. To avoid these problems, about a mile of buffer space is needed
Fig. 1. Transportation: Air.
Fig. 3. Transportation: Highway.
26 Acoustics Today, October 2009
Fig. 4. Wind Turbine: Hull, MA.