26. The volatile organic compounds emitted into the atmosphere by printing activities may, for the combined activities of an establishment, exceed the limit prescribed by the first paragraph of section 19, provided that the emission of the substances by the operator is reduced by a percentage at least equal to the percentage set out in the following table, for each type of printing process, through the use of ink or other substances having a lower volatile organic compound content or the installation of a volatile organic compound emission reduction system:
Process Percentage of VOC
emission reduction
Flexography 90
Rotogravure 90
Offset lithography with heatset ink 90
Offset lithography without heatset ink 70
Letterpress printing 70
For the purposes of this section, the emission reduction percentages are calculated on a monthly basis using the following reference parameters:
Process Solvent Ink density Percentage of
density (kg/l) solids (in volume)
(kg/l) in ink
Flexography 0.8 1.1 25
Rotogravure 0.8 1.0 25
Offset lithography 0.8 1.0 60
Letterpress printing 0.8 1.0 60