What are VOC?
Volatile organic compounds (VOC) are organic (carbon-containing) chemicals that exist as a gas at normal environmental temperatures and pressures. VOC are emitted into the atmosphere from a variety of both natural and anthropogenic sources, such as vehicles, fossil fuel combustion, steel making, petroleum refining, fuel refilling, industrial and residential solvent use, paint application, manufacturing of synthetic materials (e.g. plastic, carpets) food processing, agricultural activities, wood processing and wood burning. Certain VOC play a role in the formation of ground-level ozone and PM2.5, which contribute to smog. Other, less reactive, VOC may be transported long distances in the atmosphere.
VOC may often be odorous and some are linked to various health or environmental impacts. Most VOC are not encountered at levels that are immediately toxic, although they may cause effects on long exposure including an increased risk of cardiovascular and respiratory effects.
Several of the CASA stations monitor one or more VOC on a real-time basis (1,3-butadiene, benzene, and ethylene). These three VOC are described in further detail below.
An even wider range of VOC are monitored at several CASA stations on a non-continuous basis (every 6 or 12 days), or continuously over a 2-week period, which involves collecting a sample that is sent for laboratory analysis. The results of these VOC samples are available on the More Monitoring Data page.