Question

(a) List the six criteria pollutants and write the standards for them. (b) “Clean” air might have a sulfur dioxide (SO2) concentration of < 25 ppby, while polluted air might have a concentration of 15 ppmy. Convert these two concentrations to ug/mº. Assume a temperature of 298 K. (note the difference units of concentrations, ppmy versus ppbv)[5 pts]

Answer 1

a) The Six Criteria Pollutants are

1. Ground Level Ozone
2. Particulate matter
3. Carbon Monoxide
4. Lead
5. Sulfur Dioxide
6. NItrogen Dioxide

Pollutant	Primary / Secondary	Averaging Time	Level
Ground Level Ozone	Primary and Secondary	8 hrs	0.070 ppm
Particulate matter 2.5	Primary Secondary Primary and Secondary	1 year 1 year 24 hrs	12.0 $\mu$ g/m3 15.0 $\mu$ g/m3 35 $\mu$ g/m3
Particulate matter 5.0	Primary and Secondary	24 hrs	150 $\mu$ g/m3
Carbon Monoxide	Primary	8 hrs 1 hr	9 ppm 35 ppm
Lead	Primary and Secondary	Rolling Month average	0.15 $\mu$ g/m3
Sulfur Dioxide	Primary Secondary	1 hr 1 hr	75 ppb 0.5 ppm
NItrogen Dioxide	Primary Primary and Secondary	1 hr 1 year	100 ppb 53 ppb

b)

For Clean Air :

The general equation is ug/m = (ppb)*(12.187)*(M) / (273.15 + °C) where M is the molecular weight of the gaseous pollutant. An atmospheric pressure of 1 atmosphere is assumed.

Molecular Weight of SO₂ is 64 ; 298K = 25 ^oC ; Taking concentration as 24 ppb_v

$\mu$g/m³ = 24*12.187*64 / (273.15 + 25 ) = 62.78 $\mu$ g/m³

For Polluted Air :

ppm_v x 1000 = ppb_v

Using the same conditions as for Clean Air for Molecular Weight and Atmospheric Pressure

$\mu$g/m³ = 15*12.187*64 / (1000*( 273.15 + 25 )) = 0.039 $\mu$ g/m³