Equations

Mass Emissions

Mass Emissions (mass per time) are calculated based on measured concentration, molecular weight and volumetric flow:

lb/hr is mass emissions in pounds per hour
[conc]ppmV is measured concentration, measured in parts per million, volume
MW is molecular weight in pounds per pound-mole (lb/lb-mol)
VolFlow is Volumetric flow, measured in dry, standard cubic feet per minute (dscfm)
60 signifies 60 minutes per hour
385.4 is the number of cubic feet in a pound-mole of gas at standard temperature and pressure

lb/MMBtu is mass emissions, measured in pounds per million British Thermal Units
MMBtu/hr is the heat input to a system, measured in million British Thermal Units per hour

Oxygen-adjusted concentrations

are used to correct measured concentrations under in-situ air-diluted conditions to a reference oxygen concentration level:

[poll]@X%O₂ is the concentration of a pollutant (poll), corrected to a reference concentration (X%) of oxygen
[poll]meas is the measured in-stack concentration of the pollutant
%O₂(ref) is the reference oxygen concentration, to which the measured concentration will be corrected
%O₂(meas) is the measured in-stack oxygen concentration

Dry-basis concentration

is what the in-situ measured concentration would be if the water vapor were removed from the gas volume sampled:

ppmVd is the dry-basis pollutant concentration (moisture removed from the sampled gas volume)
ppmVw is the wet-basis pollutant concentration (moisture included in the sampled gas volume)

Conversion Between Volume and Mass-Based Concentrations:

mg/m³ is the mass-per-volume concentration of a gas
ppmV is the volume-per-volume concentration of a gas
MW is the molecular weight of the species
24.04 is the volume in liters, of one mole of gas at STP

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