Environmental Justice Air Quality Monitoring Act of 2021 This bill requires the Environmental Protection Agency to implement a pilot program to award, on a competitive basis, grants or contracts to state, local, and tribal air agencies to carry out specified projects for hyperlocal air quality monitoring systems in environmental justice communities (i.e., communities with significant representation of communities of color, low income communities, or tribal and indigenous communities that experience, or are at risk of experiencing, higher or more adverse human health or environmental effects). A project carried out using a grant or contract awarded under the pilot program may not exceed five years in duration.