Air pollution: Volatile Organic Compounds (VOCs), what is the real issue?

Air quality is a major public health issue and a real concern for stakeholders. Volatile Organic Compounds (VOCs) are among the major air pollutants. VOCs are defined as any compound of natural or anthropogenic origin that contains carbon and hydrogen (excluding methane). VOCs also include more complex substances where some hydrogen atoms may be substituted by oxygen, nitrogen, sulfur, or halogen atoms (especially chlorine or fluorine). These compounds are in the state of gas or vapor under normal conditions of temperature and pressure.

 

To date, more than 300 VOCs have been recorded in outdoor air. They constitute a group of heterogeneous substances which impact on health and the environment is highly dependent on their origin and chemical characteristics. VOCs can originate from human activities (transport, combustion, industrial processes, and solid waste) or can be of natural origin. Plants may diffuse various types of VOCs in the atmosphere and be the source of around 90% of VOCs in non-urbanized environments. Nevertheless, natural VOCs are less toxic towards human health and the environment compared to the anthropogenic VOCs (such as those originating from fossil fuels combustion). In this context, recent studies have shown a correlation between outdoor temperature and the production of natural VOCs. However, these natural VOCs may be a potential risk to human health only when very specific conditions are met. In urban areas and under high temperatures and solar radiation, naturally occurring VOCs may undergo reactions leading to the production of ozone and fine particulate matter. However, the hazard posed by natural VOCs needs to be nuanced compared to the atmospheric pollution generated continuously by the combustion of hydrocarbons from human activities (Observations from CNRS researchers:

http://www.lemonde.fr/planete/article/2017/05/20/les-arbres-peuvent-degrader-la-qualite-de-l-air_5131024_3244.html.).

 

In addition to outdoor air pollution, the indoor air pollution is also an important health issue. More than 500 VOCs have been detected in the indoor environment. These compounds are mainly produced by furniture, cleaning products, cosmetics, wood, tobacco etc. The number of VOCs and their concentrations in indoor air are significantly higher than those detected in outdoor air. Obviously this finding has a major impact on the health risks associated with these VOCs, considering that the general population in developed countries spends 90% of its time indoors. Again, the health impact of these VOCs is highly dependent on the chemical characteristics of these substances. In this context, recent studies have shown that the most volatile and reactive VOCs are also the most toxic. These substances belong in particular to the family of polycyclic aromatic hydrocarbons (PAHs). It includes toluene, benzene, and xylene, which are solvents commonly used by the industry and which can cause chronic health effects following long-term repeated exposure. Some alcohols (methanol, propanol), halogenated compounds or aldehydes (formaldehyde) are also described as proven or probable carcinogens and /or endocrine disruptors in humans. The cases of cancers resulting from occupational exposure to methanol and formaldehyde are now proven.

Finally, some epidemiological studies have revealed the existence of a link between other types of VOCs (certain essential oils, or certain acids such as acetic acid) and the appearance of allergic reactions (mainly respiratory sensitization). However, it appears that the sensitizing potential of these substances is only observed at doses much higher than those present in most formulations.

 

In conclusion, two types of VOCs can be distinguished:

 
- Highly harmful VOCs, whose long-term exposure may induce major health effects. These substances are essentially derived from the petrochemical industry and hydrocarbon combustion. These substances are generally persistent, bioaccumulative and repeated exposure may induce endocrine disrupting effects, or chronic diseases such as cancer, depending on the substances considered.

 
- VOCs with low potential health effect (such as VOCs of vegetable origin), whose exposure can generate a potential health effect only under specific conditions (peak heat associated with air pollution).
A list of the most problematic VOCs requiring monitoring in the atmosphere has been published by the Quebec Ministry of Sustainable Development, Environment and the Mitigation of Climate Change (http://www.mddelcc.gouv.qc.ca/air/cov/liste.htm).

 

 

In this context, SALVECO does not use any of the above listed substances. Nevertheless, some of our formulas are perfumed. However, in order to ensure the safety of our products, SALVECO has chosen to use exclusively 100% natural perfuming substances such as essential oils. As mentioned above, these substances can induce sensitization only at high concentrations. However, in order to guarantee the safety of its products and to avoid inhalation of these substances, SALVECO only uses concentrations, which are far below the thresholds that can trigger allergic-type responses. SALVECO takes special care in defining its formulations and proposes 100% biodegradable, non-bioaccumulative products, thus representing no risk towards human health or the environment.

 

Figure 1: Scheme showing potential health effect of anthropogenic versus natural VOCs