Environmental managers who contract for testing services will find it useful to understand some of the essential calculations and conversions that underpin the final data products.
Equations
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, 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
Unit Conversions
When converting from these units | Multiply by these conversion factors | To get to these units |
à à à à à | ||
Grams (g) | 15.4324 | Grains (gr) |
Grams (g) | 1000 | Milligrams (mg) |
Grams (g) | 106 | Micrograms (µg) |
Pounds (lb) | 453.5924 | Grams (g) |
Pounds (lb) | 0.4535924 | Kilograms (kg) |
Cubic meters (m3) | 35.31467 | Cubic feet (ft3) |
Cubic meters (m3) | 1000 | Liters (ℓ) |
Pressure (atm) | 29.92 | Pressure (in Hg) |
Grains per cubic foot (gr/dscf) | 2288.4 | Milligrams per cubic meter (mg/m3) |
Parts per million (ppm) | 1000 | Parts per billion (ppb) |
ß ß ß ß ß | ||
To get to these units | Divide by these conversion factors | When converting from these units |
Celcius and Fahrenheit:
°F = 9/5 °C + 32
°C = (°F-32) x 5/9
Kelvin (absolute temperature):
°K = °C + 273.15
Rankine (absolute temperature, Fahrenheit style):
°R = °F + 459.67
Physical Constants:
Standard Temperature and Pressure (STP) – as defined by the U.S. EPA:
Temperature: 20°C (68°F; 293K; 528°R)
Pressure: 1 atm (29.92 in Hg; 1013 mBar)
Gas volume per mole:
385.4 ft3/lb-mol (at STP)
22.4 ℓ/mol (at STP)
Molecular Weights of Commonly Emitted Gases (g/mol and lb/lb-mol) | |
Oxygen | 31.99 |
Carbon Dioxide | 44.01 |
Nitrogen Oxides (as NO2) | 46.05 |
Sulfur Dioxide | 64.07 |
Carbon Monoxide | 28.01 |
Methane | 16.04 |
Propane | 44.09 |
Benzene | 78.1 |
Formaldehyde | 30.03 |
Hydrogen Sulfide | 34.08 |
Hydrogen Cyanide | 27.025 |
You can find other useful conversions and constants at: http://www.epa.gov/eogapti1/bces/reference/reference.htm
More Helpful Links:
The Source Testing Accreditation Council (STAC) administers the ASTM D7036 accreditation program, provides resources to help firms obtain this accreditation, and maintains a list of firms who have achieved this important credential. 
The Source Evaluation Society (SES) is an industry group for advancing the applied sciences relating to air pollution source evaluation. SES administers the Qualified Source Testing Individual (QSTI) and Qualified Source Testing Observer (QSTO) certification programs. These certifications are divided into four discipline-specific examinations, which require reexamination every five years. SES also hosts the premier annual education conference for the source testing industry, the Stationary Source Sampling and Analysis for Air Pollutants (SSSAAP) conference. 
The NELAC (National Environmental Laboratory Accreditation Council) Institute is an independent authority on accrediting bodies for environmental laboratories, environmental field activities and stationary source testing firms. 
Learning organizations are described as “a group of people working together to collectively enhance their capacities to create results they really care about.” Firms that have active, engaged quality management systems will display the traits of a Learning Organization. According to Peter Senge of the MIT Sloan School of Business, a learning organization displays five key disciplines:o Systems thinking (systems of relationships)
o Personal development and mastery
o Connecting individual mental models of the business
o Shared vision of the organization
o Team learning
National Compliance Management Service, Inc. (NCMS) assists oil & gas operators with contractor pre-qualification for DOT and other alcohol & drug testing requirements.
Safety First Inc. provides health, safety, security and environmental (HSSE) products, technologies and services to enhance workplace safety. 
The US EPA Technology Transfer Network / Emissions Measurement Center is a library of reference emissions testing methods that serve as the authoritative guides to perform stationary source emissions tests. 
Environmental-Expert is a global listing service for equipment vendors and service providers in the environmental field. Users can search by company name or by a convenient list of categories and keywords. 
The EPA Student Guide to Principles and Practices of Air Pollution Control is a broad-based educational reference covering the scope of air pollution science and regulation. Chapter 7 specifically addresses “Measurement of Pollutant Emissions.” 
The Engineering Toolbox is an online set of resources, tools and basic information for engineering and design of technical applications. EPA Quick Reference of Acronyms; Conversion Factors; Numerical Constants, Symbols and Units of Measurement. 
