Grain elevators

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

Grain elevator operations release criteria air contaminants (Part 4 substances). The calculator focusses on releases to air and uses default emission factors. It can be adapted to use available 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 emissions 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 is:

E = A x EF

where:

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

Input data

The activity rate (A) is the number of tonnes of grain processed. There are individual emission factors for total particulate matter (TPM), particulate matter with a diameter less than or equal to 10 micrometres (µm) (PM₁₀) and particulate matter with a diameter less than or equal to 2.5 micrometres (PM_2.5) for each of the grain elevator processes. The total emissions for each substance will be the sum of the emissions from each process.

Substance releases

Releases for Part 4 substances