Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what the emission limit is in grams per hour for wood burning appliances in smoke control areas; and when it entered into force.

Wood may only be burned in a Smoke Control Area in a Defra exempt appliance. A Defra exempt appliance may not emit more than 5 grams of smoke per hour. The limits were first introduced in 1969 via the published document PD6434:1969, with the test methodology updated in 1994 via BS3841-1:1994.