Question

The National Ambient Air Quality Standard (NAAQS) for ozone (O3) is currently set at 75 ppbv (average concentration over an 8 hour period). If the average ozone concentration measured during an 8-hr period is 184 g/m3, will the NAAQS for ozone be exceeded? Assume T=29oC, P=1 atm.

Answer 1

Convert measured concentration of ozone from μg/m³ to mg/m³
which is equal to 0.184 *10³ mg/m³
Now convert this to ppmv using the equation below at 1 atm pressure,
c = [ ppmv * 12.187 * mol wt of O₃] / T in K
T = 273.15 + 29 = 302.15 K
0.184 = [ppmv * 12.187 * 48] / 302.15
measured conc in ppmv = 0.095039 ppmv
1 ppmv = 1000 ppbv
0.095039 ppmv = ?
cross multiply to get the answer,
measured conc in ppbv = 95.0391 ppbv
since 95.0391 ppbv (measured conc) > 75ppbv (current limit),
we can say that NAAQS for ozone has exceeded.