As several thousand chemical substancesmeet the definition of VOCs, the sources of VOCs on an industrial site are very diverse. Source classification helps to identify VOCs.
A distinction is made between primary and secondary sources of VOCs. The first are those emitted directly into the air. The latter produce VOCs through chemical reactions between compounds already present in the air.
VOC emissions are also classified into stationary sources (from a localized activity) and mobile sources (from the transport of living beings or goods, or from mobile activities).
On an industrial site, primary sources include anthropogenic sources (linked to human activity) and biogenic sources (of natural origin). Furthermore, an industrial site is home to both stationary and mobile sources.
VOC impacts and prevention
Thus, the presence of VOCs in the ambient air of an industrial building depends on both :
- type of activities and products used, handled or manufactured use of VOC-based supplies or raw materials (e.g. solvents, thinners, inks, lacquers, resins, etc.)
- VOC-emitting industrial processes (e.g. pulp manufacture, wood panel sizing, painting, etc.).
- handling waste or finished products emitting VOCs (VOC-impregnated parts, VOC-stained gloves, etc.)
building materials and cladding, furniture (office, workshop), electronic equipment, and products needed to run the business (e.g. medicine cabinet products, refrigerants, biocides, cleaning products, etc.).metabolism of humans (e.g. odors), insects or microbes (mVOCs) present in the building (e.g. metabolism of molds growing in dust or porous building materials).
Ventilation of the industrial building, which introduces “new” outside air, usually laden with biogenic and anthropogenic VOCs, which in turn come from: the use on the industrial site of vehicles or machines with internal combustion engines that pollute the air, particularly with PAHs, for logistics activities, or during external activities on site.
Ordinary emissions from sources polluting the tropospheric boundary layer: other surrounding activities (industrial, agricultural, transport, etc.); soil and water polluted by industrial discharges (chimneys, etc.), leaks (tanks, pipes, etc.), agricultural discharges (pesticide spraying, etc.), runoff, atmospheric deposits (rainwater, urban snow, etc.), plants, in the industrial site and its surroundings; interaction or reactivity between different pollutants in the environment….), runoff, atmospheric deposits (rainwater, urban snow, …), plants, in the industrial site and its environment; the interaction or reactivity between different ambient air pollutants from both indoor and “new” air.
VOC consequences and management strategies
All sectors of activity emit more or less VOCs. For example, 86 of the 88 sectors of activity in the Nomenclature des Activités Françaises, including all manufacturing industry sectors (ANESM 2023), present occupational exposure to formaldehyde.
It should also be remembered that VOC emissions can produce an ATEX (explosive atmosphere) which, in contact with heat, can cause a fire or explosion. Conversely, a fire in a building, or an explosion followed by a fire, will produce VOCs in the smoke plume.
VOC emissions can also be a source of odour nuisance, particularly emissions of sulphur compounds, amine compounds, etc.
VOCs expose employees to health and physical risks, and impact the environment of an industrial site. Identifying sources of VOCs helps to take preventive measures to preserve and improve air quality: capture at source, filtration, treatment.