Emission of VOCs lead to the formation of photochemical smog (ozone) by
reacting with oxides of nitrogen, other pollutants and sunlight. Photochemical
smog affects human health. A number of VOCs are considered to be
hazardous air pollutants, e.g. Toluene, MEK etc. Many plant oils can be used
as vehicles for pigments in ink. In fact, prior to the early 1960s, linseed, soy,
corn and canola were common ingredients in ink. Petroleum products were
substituted on a large scale from the early 60s on, primarily because presses
were running faster and needed shorter drying times. However, modern
technologies, such as UV/EB curing, do enable fast drying times using plantderived
or aqueous inks and coatings.