Abstract: A method for providing a mobile emissions reduction credit or other tradable commodity (15) comprising the steps of identifying an emissions reduction technology for a pollutant (20), providing a portable emissions measurement system (PEMS) adapted to measure emissions of the pollutant (21), providing a mobile source (16), applying the emissions reduction technology to the mobile source to provide a modified mobile source (25), connecting the PEMS to the modified mobile source (26), taking measurements of the modified mobile source (28), analyzing the measurements to develop a modified emissions amount (29), determining a target emissions amount (19), determining the difference between the target emissions amount and the modified emissions amount (30), and converting the difference between the target emissions amount and the modified emissions amount into a tradable commodity (31).