Trees: Saving Lives in NYC

See our presentation here!

Sharlene Chiu, Margaret Tian, Kevin Zhang

According to a 1994 study of air pollution removal by trees in urban areas, trees only remove 0.09% of fine particulate matter. This amounts to every tree absorbing about 8 lbs annually, based on the 1995 New York City Tree Census. At first glance, 8 lbs may seem negligible, but we were excited to discover that 7.6 lives are saved each year, thanks to the removal of particulate matter by trees!

Our data sources are listed below:

  • NYC Environment & Health Data Portal, http://a816-dohbesp.nyc.gov/IndicatorPublic/BuildATable.aspx#
  • Urban Tree Effects on Fine Particulate Matter and Human Health, https://www.fs.fed.us/nrs/pubs/jrnl/2014/nrs_2014_nowak_002.pdf
  • Air pollution removal by urban trees and shrubs in the United States, https://www.fs.fed.us/ne/newtown_square/publications/other_publishers/OCR/ne_2006_nowak001.pdf

We decided to represent our data with a stacked bar chart and highlight the different layers of information with the zoom features on Prezi. The stacked bar chart predisposes the audience to expect that the percentage of pollution removal by trees is great enough to be easily spotted on the bars. However, we headed in the opposite direction by zooming into a minuscule portion of the bar. The most striking part of our narrative is that such a small percent reduction (0.09%) can have such a substantial effect (saving $60 million and around 8 lives).

We begin by showing the entire bar, which represents all the PM2.5 produced. Then we emphasize how seemingly insignificant the amount absorbed by trees is by slowly zooming into a tiny piece of the bar.  At this point in the presentation, we expect the audience to feel that trees have a trivial effect, but we then demonstrate that trees are indeed important by zooming out and showing relevant (and big) benefits. This theme of zooming in and out to showcase scale is repeated to the end of our creative chart presentation.