# Biogas flare

Flaring biogas releases polycyclic aromatic hydrocarbon (PAH) (Part 2 substances) and criteria air contaminants (CAC) (Part 4 substances).

The calculator focusses on releases to air and uses default emission factors. It can be adapted to use site-specific emission factors if they are available. 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 is:

E = A x EF

where:

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

## Input data

A = Amount of biogas burned [cubic meters]

## Substance releases

### Part 2 and Part 4 substances

Substance Chemical Abstracts Service registry number (CAS RN)1 Part Emission factor (EF)2 EF units
PAH total Footnote *   2 0.000008714 kilograms (kg)/cubic meters(m3)
Carbon monoxide (CO) 630-08-0 4 0.00005558 kg/m3
Sulphur dioxide (SO2) 7446-09-5 4 0.00009211 kg/m3
Oxides of nitrogen (NOx), expressed as nitrogen dioxide (NO2) 11104-93-1 4 0.0004533 kg/m3
Total particulate matter (TPM)Footnote **   Footnote *   4 0.0008490 kg/m3
Particulate matter less than or equal to 10 micrometers (µm) (PM10) Footnote *   4 0.0008490 kg/m3
Particulate matter less than or equal to 2.5 µm (PM2.5) Footnote *   4 0.0008490 kg/m3