The Airport and the Environment

    Airports always have one guaranteed constant, they are noisy! Anyone who has walked around an airport can attest to the cacophony of noise that is present in the forms of aircraft and other vehicles, radio chatter, and the general commotion of many people in a given space. Noise it defined as unwanted sound, and it can be a major annoyance for anyone who lives within the vicinity. Airport noise is considered a highly detrimental environmental factor as it "can cause community annoyance, disrupt sleep, adversely affect academic performance of children, and could increase the risk for cardiovascular disease of people living" nearby (Basner et all, 2017). Given this information, it is clear to see that noise is a factor that must be taken seriously in order to mitigate its negative effects. 

A basic concept for the reduction of noise is the additive of noise barriers which can be man-made in the form of noise blocking walls, or natural in the form of a line of trees to reduce airport noise. A more technologically advanced way to mitigate aircraft noise is being researched at Purdue University. They have determined that exhaust jet noise is responsible for a significant amount of noise generated from aircraft. This "jet exhaust noise is caused by the violent turbulent mixing of the exhaust gases with the atmosphere and is influenced by the shearing action caused by the relative speeds between the exhaust jet and the atmosphere" (Purdue). However, these noise levels can be reduced when the mixing rate is sped up or "exhaust velocity relative to the atmosphere is reduced" which can be accomplished by altering the pattern of exhaust as seen in the picture (Purdue).

By making changes to both the airport itself and aircraft, it will be possible to significantly decrease the noise level present around airports. 

References:

Basner, M., Clark, C., Hansell, A., Hileman, J. I., Janssen, S., Shepherd, K., & Sparrow,     V. (2017). Aviation Noise Impacts: State of the Science. Noise & health, 19(87), 41–       50. https://doi.org/10.4103/nah.NAH_104_16

Purdue. (n.d.). Noise control (supression). Noise Control/Supression. Retrieved from             https://engineering.purdue.edu/~propulsi/propulsion/jets/basics/noise.html