U. S. Environmental Protection Agency (EPA) Audit

In 2003, the U.S. EPA completed its blind audit of specialty gases suppliers in the U.S. An independent contractor for the EPA purchased product from 11 suppliers at 14 different plants. Three EPA protocol mixtures containing Nitric Oxide (NO), Sulfur Dioxide (SO₂ ) and Carbon Dioxide (CO₂) each in a balance of Nitrogen, were purchased from each plant.
The compositions of the mixtures purchased are shown below:

	NO	SO2	CO2
Low	50 ppm	50 ppm	5.00%
Mid	400 ppm	500 ppm	12.00%
High	900 ppm	1000 ppm	18.00%

What were the results?