Carbon monoxide (CO) in outdoor air
Understand outdoor carbon monoxide, its connection to fuel burning and why it is shown separately from the European AQI.
What an outdoor CO reading describes
Carbon monoxide is a colourless, odourless gas released when fuels burn incompletely. Engines and other combustion equipment contribute to outdoor concentrations. A station reading describes its outdoor surroundings. A model value is an estimate for a wider grid cell.
Carbon monoxide and carbon dioxide are different gases. PiSpace Air’s outdoor CO figures describe ambient concentrations. Indoor CO safety depends on suitable detection equipment and local safety guidance.
Check the units
Outdoor CO datasets can report concentrations in micrograms or milligrams per cubic metre. One milligram equals 1,000 micrograms. A comparison with parts per million needs an appropriate gas conversion convention and matching averaging period.
CO can be available as a separate concentration on city or station pages. The European AQI combines five other pollutants, so a CO reading does not set its category.