Fugitive dust emissions from aggregate handling

Download the aggregate handling calculator to help you estimate the releases of the National Pollutant Release Inventory (NPRI) substances.

Aggregate handling includes loading material onto a storage pile and from the pile onto a receiving surface. These drop operations may be batch or continuous. The substances of concern from these activities are criteria air contaminants (Part 4 substances). Emissions from wind erosion or from loader/truck traffic around the storage pile may also need to be considered but are not part of this calculator.

The calculator focusses on releases to air and uses default emission factors. It can be adapted to use site-specific emission factors. If you want to use a site-specific emission factor, enter it in the emission factor column, but be sure to convert the units correctly. 

The spreadsheet calculators use emission factors based on uncontrolled emission sources. If you use an emission control device and the default emission factor is uncontrolled, use this formula to adjust the spreadsheet calculation:

Controlled emissions = uncontrolled emission x ((100 - control efficiency)/100)

Since NPRI reporting thresholds are for the facility as a whole, you may need to combine the air releases you calculate with releases from other sources at your facility.

The following sections explain how the spreadsheet calculator works.

Suggested estimation methodology: emission factor

The general equation for estimation using an emission factor:

E = A x EF

where:

• E = emissions
• A = activity rate
• EF = emission factor

Input data and substance releases

The emission factors for estimating particulate emissions from a drop operation can be calculated as a function of the particle size, mean wind speed, and material moisture content. The methodology is explained in detail in chapter 13.2 of the U.S. Environmental Protection Agency (EPA) AP-42 document and summarized here.

1. determine M, the moisture content of the material (should be between 0.25 - 4.8%)
2. determine U, the annual mean wind speed for your area. Annual mean wind speed data is available at the climate data website. You will need to convert the data to units of m/s
3. calculate the emission factors¹ for total  particulate matter (TPM)*, particulate matter less than or equal to 10 micrometers (µm) (PM₁₀)* and particulate matter less than or equal to 2.5 µm (PM_2.5)* using these formulas:
   EF_TPM = 0.74(0.0016)[(U/2.2)^1.3 / (M/2)^1.4]     (kilograms (kg)/tonne)
   EF_PM10 = 0.35(0.0016)[(U/2.2)^1.3 / (M/2)^1.4]     (kg/tonne)
   EF_PM2.5 = 0.053(0.0016)[(U/2.2)^1.3/ (M/2)^1.4]     (kg/tonne)
4. use the calculated emission factors to determine the annual emissions of each substance using the general equation for emissions estimation:
   E = A x EF
   where:
   E = annual emissions (kg)
   A = activity rate (tonnes of aggregate loaded per year)
   EF = emission factor (kg/tonne)
   Do this calculation separately for each substance (i.e. E_TPM = A x EF_TPM, E_PM10= A x EF_PM10, and E_PM2.5 = A x EF_PM2.5)