Carbon Monoxide
Description
Carbon monoxide is a gaseous pollutant with the chemical formula CO. It has no colour, no odour and no taste. It is flammable in concentrations of 12 to 75%.
Sources
Carbon monoxide is predominantly produced as a result of incomplete combustion of carbon-based fuels such as coal, biomass, oil, natural gas and biogas. Usually efforts are made to reduce incomplete combustion to burn fuels more efficiently, however in some cases incomplete combustion is favoured such as in the production of charcoal and coke (from wood and coal respectively) or in the production of synthesis gas (H₂ + CO).
Environmental Impact
Carbon monoxide is a temporary atmospheric pollutant commonly found in urban areas. Inhalation of high concentrations of carbon monoxide can be fatal to humans. Carbon monoxide also plays a role in the production of other pollutants such as ground level ozone (O₃).
Control
Carbon monoxide is commonly controlled by improving combustion efficiency to gain complete combustion. This can be done in several ways, by altering parameters such as air-to-fuel ratio, combustion temperature and turbulence or by use of a secondary combustion chamber.
Measurement
Alkali Environmental perform periodic measurements of Carbon Monoxide in ducted emissions from point sources to the standard reference method BS EN 15058. The reported results carry UKAS and MCERTS accreditation where the method can be performed to the standard.
These measurements are taken using an on-line combustion gas analyser where instantaneous and logged results can be taken. Often reported results are corrected for oxygen concentration to avoid the affect of dilution air on the result.
Emission Limits
Some examples of common carbon monoxide emission limits:
100mg/m³ – Thermal Oxidisers
100mg/m³ – Cremators
225mg/m³ at 6% O₂ – Biomass Combustion (>1MWth)
375mg/m³ at 6% O₂ – Biomass Combustion (<1MWth)
1400mg/m³ at 5% O₂ – Landfill Gas / Biogas Engines (post-2005)
1500mg/m³ at 5% O₂ – Landfill Gas / Biogas Engines (pre-2006)