In preparation of taking decibel measurements at various points along the multiple subway lines, I first explored what apps are available for Android phones, and whether these apps are accurate. According to a 2014 study by the Centers for Disease Control, the smartphone sound apps are useful for making "quick spot measurements" to determine if noise levels are too high. See: http://blogs.cdc.gov/niosh-science-blog/2014/04/09/sound-apps/
However, the CDC report was very particular about which apps passed muster for use in its study, and favored apps written for Apple iOS devices. Whether microphones and software features of Android devices have caught up in the subsequent two years is worth looking into, but in any case, a careful selection of which app to use is probably more important. It would also be helpful to know how the built-in microphone compares to an external mic; simply moving the phone around in silence creates pressure on the built-in mic, which registers as noise in the apps I have tested so far.
Regardless, it seems that reasonably accurate measurements should be sufficient for this project. In similar investigations, it has already been determined that subway riders in New York City are indeed subjected to dangerous noise levels: http://www.newsday.com/news/new-york/subway-noise-can-damage-your-ears-say-experts-1.6164286
Unfortunately, these studies seemed to focus more on sound levels on the subway platform than on board the trains. It is important to note that lower sound levels over a longer duration can have an equally deleterious effect on hearing.
Keep in mind that playing music or other audio through headphones is not a form of hearing protection. On the contrary, this only compounds the problem: http://www.hear-it.org/30-minutes-in-new-york-subway-can-damage-the-hearing
Until next time, see you on the T.
No comments:
Post a Comment