Significant harm levels are reached when any one of the following pollutant concentrations are measured:

(1) Sulfur dioxide - 2,620 µg/m3 (1.0 ppm), 24-hour average.

(2) PM-10 - 600 micrograms/cubic meter, 24-hour average.

(3) Carbon monoxide - 57.5 mg/m3 (50 ppm), 8-hour average, 86.3 mg/m3 (75 ppm) 4-hour average, 144 mg/m3 (125 ppm) 1-hour average.

(4) Ozone - 1,200 µg/m3 (0.6 ppm) - 2-hour average.

(5) Nitrogen dioxide - 3,750 µg/m3 (2.0 ppm) 1-hour average, 938 µg/m3 (0.5 ppm) 24-hour average.