Carbon monoxide is of concern mainly because of its effects on human health and its role in tropospheric ozone formation. As a result, carbon monoxide is one of the pollutants covered by the Government's Air Quality Strategy. No exceedences of the health-based ambient air quality objective have been recorded in the UK for several years.
According to the National Atmospheric Emissions Inventory, over 90 per cent. of the annual UK emissions for 2001 resulted from incomplete fuel combustion, largely from road transport. The contribution of agriculture to the total is small, so organic farming is not expected to have a measurable effect on the total.