What are VOCs?
Volatile Organic Compounds (VOCs) are chemicals emitted as gases from various solids or liquids. “Volatile” refers to their ability to easily evaporate at room temperature, whilst “organic” simply means that they include carbon. The chemicals in this group are wide-ranging, with varying levels of toxicity. Whilst methane is a VOC, it is usually treated separately to other VOCs due to its significant environmental impact contributing to climate change, and its low photochemical reactivity.
VOCs play a significant role in the formation of ozone and fine particulate matter, which contribute to smog. VOCs and nitrogen oxides act as precursors which, under sunlight, react to create ozone and fine PM, significantly contributing to urban outdoor air pollution.
Where do they come from?
VOCs are emitted from a wide array of sources, including numerous household products such as solvents, paints, aerosol sprays, printing inks, cleaning products, and stored fuels. A significant outdoor source is fuel combustion from vehicles.
Indoor concentrations of VOCs tend to be much higher than outdoors, on average 2-5 times higher.
How do they affect our health?
VOCs can range hugely in their composition: some VOCs are highly toxic (such as benzene, a known carcinogen) whilst others have no known health effects. Like other pollutants, VOCs can have different effects on people’s health depending on length of exposure.
Short-term effects include:
· Irritation of eyes, nose, throat
· Nausea / vomiting
· Aggravation of asthma symptoms
Long term effects can include increased risk of:
· Liver damage
· Kidney damage
In contributing to the formation of ozone and PM2.5, VOCs also indirectly contribute to the significant health effects of both these pollutants.
To protect oneself from the higher indoor concentrations of VOCs, the most effective precaution is to minimise the number of sources in your home. In addition, keeping windows open and ventilating the indoor environment with fresh air can dilute and lower VOC concentrations.
In contributing to the formation of ozone, VOCs indirectly facilitate damage to plant life, including decreased crop yields, and increase in plants’ susceptibility to threats such as disease.