change EJ scales to percentiles?

[ericnost]

Currently there are different scales in use. For instance, "% people of color" is measured as a percentage and "Diesel particulate matter level in air, µg/m3" is measured in µg/m3.

If users read the "EPA defines this as:" section this wouldn't necessarily be an issue, but the problem comes when they click on neighborhoods on the map and the pop-up incorrectly implies everything is a percentage.