VOC or Volatile Organic Compound is a molecule which is made up of carbon and hydrogen atoms and which evaporates rapidly into the atmosphere from its liquid or solid state. When an aerosol is used, VOCs are emitted during diffusion because of the components used: gases and solvents. The rate of emission is related to the amount of solvent. Water-based paints reduce the VOC content by replacing the solvent with water, and contribute to the respect of the environment.