A sample of air has been collected from above an air stripping tower to evaluate its performance and to determine if toxic air emission standards are being violated. The tem[erature at the time of collection is 18C, and the atmospheric pressure was 740 mm Hg. The concentration in the sample were 4.8 mg/m^3 of benzene, 1.7 mg/m^3 of PCE, and 2.0 mg/m^3 of methylene chloride. What are the concentrations of ppm?