What is VOC in Decorative Paints?

Introduction

Today protecting the environment and human health has transformed from the desired policy objectives into part of our everyday life. One of the possible ways to improve air quality and reduce damage to the environment is by choosing low VOC decorative paints and similar products. Paint industry professionals, designers, painters and even families buying decorative paint for their DIY children’s room project can contribute to limiting the VOC emissions. The next step after being aware of the VOC impacts is making informed choices.

This blog post provides an insight into the following topics:

• What is a  comprehensive definition of the VOC?
• What are the effects of VOC on human health and the environment in general?
• How are the VOC emissions regulated in the paint products marketed in the European Union?
• What are the main benefits of VOC reduction and how to achieve it?

What Is VOC and Why Does It Matter?

VOC is one of the most commonly used terms in the paint and coating industry ranging from the VOC content to low-VOC and even zero-VOC. It is well known (or can be found with some clicks) that VOC is an abbreviation for volatile organic compound. However, without strong background in chemistry it could be still not easy to understand, what VOCs really are and why they receive so much attention. 

Scientific articles: 

• Volatile Organic Compounds: Do they present a risk to our health?  
• Increased long-term health risks attributable to select volatile organic compounds in residential indoor air in southeast Louisiana.

First, there are various ways of defining the limits and characteristics of VOC, such as based on Vapour Pressure (> 10 Pa at 20°C), Boiling Point (< 250°C or 280°C) or photochemical oxidant creation potential. Each of these approaches have their own merits and supporters. However, it should be noted that a boiling point limit of 250°C excludes important coalescing solvents with boiling points of > 250°C. Therefore, if the focus is on decorative paints, all volatile organic compounds used in decorative paints are included under this definition from the study completed on the behalf of the European Commission: 

VOCs are all organic compounds used in paint or associated with the application of paints that have an initial boiling point of lower than 280°C” ^(a)

Namely, the VOCs are chemicals that easily evaporate during the application and curing of paints. Their main purpose is acting as a medium helping to transfer the paint to the surface and aiding the paint's flow. Once the desired paint is applied, the carrier evaporates leaving behind a solid coating.

Other important characteristics of the VOCs include their health and environmental impacts.

Volatile Organic Compounds are toxic chemicals that easily evaporate into the air and accumulate in the indoor environment where you breathe. VOCs can also escape into the atmosphere and form smog. ^(b)

Health impacts If these chemicals are inhaled, especially during prolonged period of time, it could lead to serious health problems. Depending on the duration and intensity of exposure, it could be irritation of the eyes and respiratory tract, nausea, dizziness or more serious illnesses including heart, lung or kidney damage and even cancer. As with many other chemicals, young children and the elderly could suffer the most from the harmful effects of the VOCs as well as people who have chemical sensitivities or weakened respiratory or immune systems. 

Environmental impacts VOCs are one of the primary air pollutants others being Nitrogen oxide (NOx), Carbon dioxide (CO2), Sulphur oxide (SOx) etc. Taking into account that in the VOCs are supposed to evaporate out of the drying paint layer, it can be easily understood that they end up in the troposphere, the lowest layer of the earth’s atmosphere. According to the above mentioned definition of the VOCs, it includes such substances as solvents, co-solvents, coalescent agents, monomers and other possible volatile additives including biocides. 

The Recent History of the VOC Regulations in the European Union

In the European Union the Directive 2004/42/EC on the limitation of emissions of volatile organic compounds due to the use of organic solvents in certain paints and varnishes and vehicle refinishing products, which is also known as the ‘Paints Directive’, aims to limit the total content of VOCs due to the use of organic solvents in certain paints and varnishes and vehicle refinishing products. This would prevent or reduce air pollution resulting from the contribution of VOCs to forming ozone in the troposphere.

The directive defines the technical specifications for certain paints and varnishes (excluding aerosols) and vehicle refinishing products. Mainly these are coatings applied to buildings or similar structures and vehicles. Full list of these products is included in Annex I of the above mentioned directive. In addition, the directive is complemented by the Regulation (EC) No 1272/2008 on the labelling of chemical substances and preparations. It places the responsibility on EU countries to ensure that the products falling within the scope of the regulations are marketed only, if their VOC content does not exceed the limits set out in Annex II of the directive (ranging from 30 to 750 grams/litre (g/l) for paints and varnishes) and comply with the labelling requirements. The label must indicate:

• the subcategory of the product and the relevant VOC limit values in g/l;
• the maximum content of VOC in g/l for the product in a ready-to-use condition.

Annex II of the Directive 2004/42/EC also comprises a list of VOC content limit values for vehicle refinishing products.

In 2008 the European Union has introduced Ecolabel criteria. The paint products corresponding to these criteria can obtain EU Ecolabel. These criteria have been updated regarding the VOCs in 2014. The current version of the EU Ecolabel for indoor and outdoor paints and varnishes meet criteria that guarantee:

• Minimized content of hazardous substances;
• Reduced content of volatile organic compounds (VOCs): x g/l;
• Good performance for (both) indoor (and) or outdoor use.

European Commision, in year 2018 introduced “EU green public procurement (GPP) criteria for paints, varnishes and road marking”. The development of EU GPP criteria aims to help public authorities ensure that the goods, services and works they require are procured and executed in a way that reduces their associated environmental impacts. The criteria are thus formulated in such a way that they can be, if deemed appropriate by the individual authority, integrated into its tender documents with minimal editing. ^(d)

As decorative paints and other paint products can be goods included in the public procurement, it was necessary to define GPP criteria for paint products thus promoting the use of products, which:

1. Have lower environmental impact along their life cycle;
2. Are of high quality (have good performance and long durability);
3. Contain a limited amount of hazardous substances and VOCs. High quality and performance standards of the paint are required to ensure the longevity of the product and contribute that way to the significant reduction of the paints’ overall life cycle impacts. The proposed EU GPP criteria should not entail significant cost increases to the public contracting authority when evaluated using a life-cycle cost perspective (e.g., lower overall costs due to better durability and less frequent need of repainting). ^(e)

Table no.1

The Benefits from the VOC Reduction

VOCs have been identified as substances with negative effects involving health effects, global warming, ozone layer depletion, fauna and flora degradation. 

Not feeling well after completing the DIY children’s room project probably does not mean only working too much as many VOCs used in decorative paints have short- and long-term adverse health effects ^(f). According to various research studies VOC emissions can lead to eye, nose, and throat irritation, headaches and loss of coordination. Other more severe reactions to VOC exposure for prolonged periods are damage to liver, kidney and central nervous system. In addition, some of the VOCs are suspected to be carcinogenic. Thus it is worth to pay attention, if the paint has an EU Ecolabel or similar quality label indicating that they have reduced content of VOC.

Switching to the decorative paint products with low-VOC and even zero-VOC levels has direct environmental benefits as well as it leads to the reduction in ground level concentrations of ozone. As it was mentioned in the previous sections, the VOCs play a significant role in the formation of ozone in the troposphere. Under sunlight, VOCs react with nitrogen oxides emitted mainly from vehicles, power plants and industrial activities to form ozone, which in turn helps the formation of fine particulates. The accumulation of ozone, fine particulates and other gaseous pollutants results in smog that reduces visibility.  The economic growth in urban areas comes with increased formation of these pollutants, thus aggravating the regional smog phenomenon. Smog is particularly severe under strong sunlight and stagnant weather conditions, e.g. a typhoon approaching, or northerly winds that are common in autumn ^(k). The types of environmental potential benefits associated with the lowering of ground level ozone concentrations include reductions in the potential of the following ozone-related impacts ^(h):

• Human health - reduction in acute mortality and morbidity;
• Human health - reduction in chronic mortality and morbidity;
• Reduction in damage to crops;
• Reduction in damage to materials (e.g. paint, rubber, textiles); and
• Reduction in damage to forests and ecosystems.

How to Reduce VOCs in Decorative Paint Products?

Being aware of the negative effects of VOCs on human health and the environment the paint and coatings industry is working towards finding alternative solutions for decorative paint products that comply with the EU environmental targets. The current industry trends highlight 3 main areas allowing to achieve significant VOC reductions:

1. Switching from solvent-based to water-based products By switching from solvent-based to water-based coatings offer many benefits for both industrial paint and paint for wood sectors. Though in the short term solvent-based products can seem an easier option as during the curing phase they have lower temperature and humidity requirements, the water-based products offer such long term benefits as lower carbon footprint, compliance with the latest environmental rules and significantly lower risks to the human health. 

2. Increasing the solids content (high solids) By changing the proportion of various paint components, it is possible to change the finish and qualities of the decorative paint. Compared to the low solid paints with the average solid content of 25%  and solvent content of 60%, the solid content in the high solid paint products exceeds 60% thus leading to lower amounts of VOCs per liter of liquid paint.  

3. Using powder coatings in lieu of liquid paints The main advantage of powder coating is that they contain zero VOC. In addition, it is possible to apply thicker coat of powder coating without sagging or running and they are less demanding regarding the curing conditions. 

Resources for VOC in Decorative Paints:

• The Paints Directive: link.
• Project website for a study, prepares the ground for EU Ecolabel criteria: link.
• EU Ecolabel criteria: link. 
• EU Green Public Procurement criteria: link.
• EPA, Volatile Organic Compounds' Impact on Indoor Air Quality: link.  

Closing

It is well known that VOCs are toxic chemicals used in decorative paint products or associated with the application of paints. They easily evaporate having negative effects on the human health as well as contributing to the air pollution.

In the EU level ‘Paints Directive’ is the main document aimed specifically at limiting the total content of VOCs due to the use of organic solvents in certain paints and varnishes and vehicle refinishing products. In addition, indoor and outdoor paints and varnishes are among the products, which can be awarded with the EU Ecolabel, if they correspond to certain environmental excellence criteria.

Thus switching to the decorative paint products with low-VOC and even zero-VOC levels reduces the risks of health problems as well as has direct environmental benefits as well as it leads to the reduction in ground level concentrations of ozone. The main trends in the paint and coatings industry for finding the solution to reduce VOCs in decorative paints include:

1. Switching from solvent-based to water-based product;
2. Increasing the solids content in the paints;
3. Using powder coatings in lieu of liquid paints.