The data was gathered from this source, which is the same source the data from the first project was gathered; the EPA's official website.
This time, since there was so much data (collecting daily and hourly data as opposed to just yearly), the data had to be processed in a way that made it less vast, and therefore 'palatable' in R. Without this extra measure taken, the file wouldn't have been able to be read in to begin with. Furthermore, attempts to display data by accessing this file in the directory, rather than the massaged data, will result in nothing being displayed, with the error message 'No data found' presented on ShinyDashboard.
This is the data folder we used. If one would like to run this app from R Studio, then the data must be within the same folder as the app.