Volatile Organic Compounds or VOCs are organic chemicals – any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon – VOC have the property of high equilibrium vapor pressure at room temperature. Meaning: as the temperature of a state of affairs (say a liquid) increases, the kinetic energy of its molecules also increases. As the kinetic energy of the molecules increase, the number of molecules transitioning from liquid into vapor also increases – essentially VOCs are the tendency to allow the escape of particles from liquid/solid/gas closed systems (objects – like an air freshener).
VOCs include both man-made and naturally occurring chemical compounds – while the scientific language is rather dense and the pseudoscientific language presents us with a picture of VOCs as belonging to end all be all of commercially manufactured and environmentally unconscious corporate/government bodies (demonization); it is no wonder there are levels of confusion regarding something of a mundane phenomena.
VOCs are ubiquitous (synthetic or natural) – in fact, our sense of scent and ability to concretize odor profile is to some degree possible thru VOC vapor – for example, think about this: if wishing to assess one’s exposure risk to say, limonene – which reacts with ozone to form formaldehyde – would you (i) prefer to remain in an enclosed space with a lemon scented air freshener (using d-limonene as base) with periodic introductions of ozone or ii) remain in an enclosed space slowly peeling oranges with periodic introductions of ozone? – silly as this thought experiment may sound, it has the potential to show something of interest.
The inclination to choose option (ii) is strong – clearly option (i) leads to the direct exposure to formaldehyde. The reasoning could have gone like this – ‘given that the conditions of the room do not change and the exposure to ozone is less of a concern (I’m being exposed to it now); the objects in the room are of the most concern. The air freshener is artificial, being used atypically and uses commercially generated compounds – the orange is natural, familiar and it actually aids to sustain life (I can eat it: they’re quite good). Room ii) is the better choice to mitigate exposure.’ This line of thought comes easily – fluidly in fact – presents a practical examination of the scenario and reaches a solid abductive conclusion. Logical analysis shows the reasoning to be fallacious however – appeal to nature. Room i) is the better choice – in a study done by Langer et al, exposure to limonene from peeling an orange is far greater than using limonene-scented products. The study showed that secondary organic pollutants (in our case formaldehyde) exist in the lowest range of exposure from artificial d-limonene sources and that a higher concentration of particulates are formed by peeling an orange.
Langer S, Modanova J, Arrhenius K, Ljungstrom E, Ekberg L. Ultrafine particles produced by ozone/limonene reactions in indoor air under low/closed ventilation conditions. Atmospheric Environment. 2008;42:4149–4159.