
pollutant 
federal primary standard 
North Dakota standard 

total suspended particulates (TSP) 
75 µg/m^{3}
annual geometric mean
260 µg/m^{3}
24hr. average 
60 µg/m^{3}
annual geometric mean
250 µg/m^{3}
maximum 24hr. average 
settled particulates (dustfall) 
none 
15 tons/sq. mile,
maximum 3month arithmetic mean
in residential areas
30 tons/sq. mile,
maximum 3month arithmetic mean
in heavy industrial areas 
sulfur dioxide 
0.03 ppm (30 µg/m^{3})
annual arithmetic average
0.14 ppm (365 µg/m^{3})
24hr. average 
60 µg/m^{3}
(0.02 ppm) maximum annual
arithmetic mean
260 µg/m^{3}
(0.10 ppm) maximum
24hr. concentration
715 µg/m^{3}
(0.24 ppm) maximum
1hr. concentration 
reactive sulfur 
none 
0.24 mg/100 cm^{2}/day,
maximum annual arithmetic mean
0.50 mg/100 cm^{2}/day,
maximum for 1month period 
suspended sulfate 
none 
4 µg/m^{3}
12 µg/m^{3}
maximum annual arithmetic
mean; maximum 24hr.
concentration not to be exceeded
over 1% of the time
30 µg/m^{3}
maximum 1hr concentration
not to be exceeded over
1% of the time 
foliar fluoride 
none 
none 
sulfuric acid mist, sulfur trioxide, or combination 
none 
4 µg/m^{3}
maximum annual arithmetic mean
12 µg/m^{3}
maximum 24hr.
concentration not
to be exceeded over
1% of the time
30 µg/m^{3}
maximum 1hr.
concentration not
to be exceeded over
1% of the time 
hydrogen sulfide 
none 
45 µg/m^{3} (0.032 ppm)
maximum halfhour concentration
not to be exceeded more than twice in any
five consecutive days
75 µg/m^{3} (0.054 ppm)
maximum halfhour concentration
not to be exceeded more than twice a year 
carbon monoxide 
9 ppm (10 mg/m^{3})
8hr. average*
35 ppm (40 mg/m^{3})
1hr. average* 
10 mg/m^{3} (9 ppm)
maximum 3hr. concentration*
40 mg/m^{3} (35 ppm)
maximum 1hr. concentration* 
nitrogen dioxide 
0.05 ppm (100 µg/m^{3})
annual arithmetic average 
100 µg/m^{3}
(0.05 ppm) maximum
annual arithmetic mean
200 µg/m^{3} (0.10 ppm)
maximum 1hr.
concentration not to be exceeded
over 1% of the time in any 3 months 
photochemical oxidants (ozone) 
0.12 ppm (235 µg/m^{3})
1hr. average* 
235 µg/m^{3}
(0.12 ppm) maximum
1hr. concentration* 
hydrocarbons (less methane) 
24 ppm (160 µg/m^{3})
3hr. concentration
(69 AM)* 
160 µg/m^{3} (0.24) ppm
maximum 3hr.
concentration (69 AM)* 
lead 
1.5 µg/m^{3}
calendar quarter average 
1.5 µg/m^{3}
quarterly arithmetic mean 
visibility 
none 
0.4 coefficient of haze
per 100 linear feet maximum annual geometric mean
(coefficient of haze) 