Calculating Emissions Using AP-42 Emission Factors Marti Blad, PhD

2 What We Will Learn  How AP-42 can be a useful planning tool  How to find & use AP-42 emission factors

3 What is AP-42?  Reference document used for estimating emissions from sources  Point source processes & equipment  Area source groupings and activities  A way for EPA to document emission factors  AP-42 does NOT contain recommended emission limits or standards

4 Emission Factors  Representative values  Attempts to relate quantity of pollutant released with activity or event responsible for release of that pollutant  Facilitate estimations of emissions  Averages compiled from EPA studies  Assume half of sources have emissions above estimate (and half below)  Influenced by many other conditions  Actual material used  Control equipment use and efficiency

5 Emission Factors (AP-42)  General Expression E = A x EF X (1-ER/100)  E = emissions (mass of pollutant emitted)  A = activity or activity rate  EF = emission factor  ER = overall emission reduction efficiency (%)  Emission reduction (ER) efficiency not as important in simpler calculations; won’t be used in this exercise

6 Emission Factors (AP-42)  General use (PM & rock crushing example) PM Emitted = EF x tons of rock crushed  Another way to look at it Pollutant mass emitted (e.g., pounds of PM) Activity-related mass, volume, distance or duration (e.g., ton of rock crushed)

7 Using Emissions Factor Example: Rock Crushing Facility  What do we want to find?  Daily emission of PM 10  Uncontrolled crushing & screening of fines  What is the process-related “activity”?  Check AP-42: it can be used to help plan!  Daily amount of material crushed & screened = 4000 tons rock per day

8 Using Emissions Factor Example: Rock Crushing Facility  Step 1: Look up Emission Factor in AP-42  Find the right crushed stone “process”  Fines crushing  Fines screening  Know the right “pollutant”  PM 10  Select the right “emission factor” (pay attention to UNITS)  Fines crushing: lbs PM 10 / ton material “crushed” lbs PM 10 / ton material “crushed”  Fines screening: lbs PM 10 / ton material “screened” lbs PM 10 / ton material “screened”

9 Using Emissions Factor Example: Rock Crushing Facility Step 2: Calculate the PM 10 emissions Fines crushing: lbs PM 10 x 4000 tons material = 60 lbs PM 10 /day lbs PM 10 x 4000 tons material = 60 lbs PM 10 /day ton material day ton material day Fines screening: lbs PM 10 x 4000 tons material = 288 lbs PM 10 /day lbs PM 10 x 4000 tons material = 288 lbs PM 10 /day ton material day ton material day

10 Summary Finding the right emission factor 1.Identify correct processes 2.Know pollutant of concern 3.Pay attention to table headers/footers  Information on appropriate units  Other information on processes or conditions that may affect calculations