Crowd Sourcing of Environmental Data Act of 2017 This bill amends the Clean Air Act to give states the option of monitoring lead, ozone, particulate matter, or sulfur dioxide by greatly increasing the number of air quality sensors under their state implementation plans. The Environmental Protection Agency: (1) may not enforce a requirement concerning the method of monitoring unless the state is acting in bad faith, and (2) must allow states to base determinations on whether national ambient air quality standards for the air pollutants were exceeded on data derived from such monitoring.