DEFRA – LAQM chimney height calculation guidance

• Last modified: 23/09/21
• Website: laqm.defra.gov.uk

LAQM guidance on calculating an appropriate chimney height to ensure emissions of NO2 from small gas boilers controlled by the Clean Air Act do not lead to an exceedance of the Air Quality Strategy's objective for nitrogen dioxide (NO2) prescribed in the Air Quality Regulations 2000