Filtering and Retrofitting the Environment for Safe and Healthy Activities Indoors and Revenue (FRESH AIR) for Businesses Act This bill allows employers a payroll tax credit in each calendar quarter through 2021 equal to 50% of the cost of qualified ventilation, zoning, and air filtration and purification expenses. This includes the purchase and installation of a heating, ventilation, and air conditioning system, updates to such systems, and the purchase of any air filter, air cleaner, or air purifier. The maximum amount of this credit for any employer may not exceed $15,000 for all calendar quarters. The bill requires the Environmental Protection Agency to establish a framework and guidelines for a voluntary label to certify that air pressure, ventilation, zoning, fresh air intake, purification, or filtration systems meet the standards established by this bill.