Why do we need to monitor gases?
The severity of pollution in many cities and at specific locations leads to the detection of a wider selection of pollutants that is covered by the Air Quality Index (AQI).
Of particular significance are concentrations of Volatile Organic Compounds (VOCs).
VOCs that are released from vehicles include unburnt hydrocarbons, which of themselves may be harmful, but also contribute to urban smog.
Locations of specific interest are:
- Roadways in which air mixing is very limited such as urban canyons, tunnels, and congested inner city streets.
- Car parks and bus and transport vehicle depots.
- Refuelling forecourts
- Downwind of industrial sites that substantially engage VOCs in manufacturing (e.g. of plastics) and processing (e.g. as solvents).