But how much of these hazardous VOCs are emitted during painting operations?
In order to provide a better quantitative insight about emitted VOCs, we briefly describe two real-world scenarios here.
Automobile painting process
Automobile paint serves several purposes. On the one hand, it provides scratch, wear and weather resistance. On the other hand, it makes the car appealing to customers. The car paint conventionally consists of three layers: Primer, Basecoat & Clearcoat (varnish).
Most VOCs pollutants in the automobile life cycle are released during the manufacturing phase, while the painting stage is responsible for more than 90% of the emissions [3], [4].
As reported in the literature, typical car manufacturers use around 6.5 kg/vehicle of solvents [5].
Additionally, considering 10.8 million passenger cars manufactured in the European Union in 2020 [6]; a straightforward calculation leaves us with more than 70000 tons of solvent emitted only within the EU in that year.
Shipyard painting
One of the most important sources of pollutants from shipyards is the VOCs from the painting solvents. Marine paints VOC content in solvent-based paints can amount to 800 g/L, but it is much lower in thinned paints, and it can be something approximately 100 g/L [7], [8].
In terms of size and value, the marine coating was worth $11 billion and on a volume of more than 2000 million liters in 2016 [9]. Despite the fact that all these 2000 million liters of paint are not all solvent-based, the emitted amount of VOCs released are still beyond our expectations (~200000 ton).
These two examples of coating in the automobile and maritime industries clearly show that besides the well-known forms of pollution from burning fossil fuels, there are other types of pollution that we yet need to build knowledge around.
VOC gases emitted into the air from the painting processes of these industries are harmful by themselves. However, similar to other pollutants, the extent and nature of the health effect will depend on many factors, such as the level of exposure and length of time exposed.
To sum up, the considerable amount of the VOCs released to the environment as the byproducts of coating in these two industries heightens the need for new VOCs reduction technologies such as eco-friendly paint formulas and innovative coating application methods.
So, how can we reduce VOCs?
Attempts to reduce the solvent contents and eventually VOCs have resulted in the development of water-based, radiation-cured, and powdered paints. However, the use of these reformulations has been limited for multiple reasons [5], [10]. Long-term solutions for decreasing VOCs pollution would require more reduction than what is achieved so far only by reformulations.
For this reason, developing technologies that increase the feasibility of capturing VOCs during the coating process is the key to accomplish clean environmental goals.
In this context, young companies such as Qlayers will play a significant role in the upcoming era of addressing health and environmental problems. Qlayers has designed a patented hood system that can extract the paint VOCs and PMs, preventing them from being released into the air as well as collecting the portion of the VOCs evaporated during the atomization and spray development.
Furthermore, this technology reduces paint waste due to overspray prevention. As a result, less paint is needed for applying a certain layer thickness and eventually less amounts of VOCs being released into the air.
In the next articles, we will dig deeper into environmental issues of spray coating, and technologies deployed in paint and coating industry.
Paint is not only primarily used for decoration and protection but also for the maintenance of existing products and infrastructures. It typically includes:
To produce each of these components, various chemical substances are used. During the process, some byproduct waste and pollutants