Simply put, today’s architectural paints are cleaner – the market is dominated by waterbased technology! While the contribution to indoor air quality and overall environmental and health hazards are improved relative to solvent based paints, waterbased paints can contribute VOC’s (Volatile Organic Compounds) to the environment. These organic compounds are routinely added to paints to enhance performance. In fact, without some solvent it is more challenging to deliver good application properties, good film properties, and good overall stability of the paints.
As the paint dries, the solvent in the formulation evaporate – it is these evaporating compounds that we refer to as VOC’s. With environmental awareness at an all time high, formulators and suppliers alike are working feverishly to reduce the remaining VOC’s in waterbased paints.
VOC’s impact indoor air quality in different ways – primarily as an irritant or as a contributor to greenhouse gas emission. The expectation is that lowering VOC’s in paints will reduce harmful emissions. Recent estimates show that architectural coatings contribute roughly 4% of Total North American greenhouse gas emission.
VOC’s and Smog:
VOCs react with oxygen in the presence of sunlight to form ozone – "bad" ozone.
It is important to distinguish between "good" ozone and "bad" ozone.
"Good" ozone occurs naturally in the stratosphere about 6 - 31 miles above the ground, which protects the surface of the earth from harmful ultraviolet rays and acts to protect plants, animals and humans from its various harmful effects.
"Bad" ozone occurs at ground level, forms through the chemical reaction between VOCs, oxygen and sunlight, and is an irritant for the mucous membranes. It can also cause nose, eye, and throat irritations; and can lead to shortness of breath, coughing, and asthmatic symptoms. This "bad" lower-atmosphere ozone can also damage vegetation – plants, trees, bushes – and such impacts negatively on those dependent on nature for their livelihood. This ozone also has a corrosive effect on certain man-made materials: for example, it accelerates the deterioration and fading of certain paints.
Other industries such as transportation, generates significantly more emissions. And paint is not the only contributor to VOC’s in the household – other products such as household cleaners contribute more VOC’s than paints.
A further major consequence of VOC emissions is global warming – VOCs play a significant role with respect to the creation of the greenhouse effect. Further, some chemically very stable VOCs participate in the destruction of the stratospheric ozone layer (the "good ozone") – this is the famous hole in the ozone layer.
Today, scientists recognize that not all VOC’s are created equally. As a result the debate is shifting to include reactivity considerations and not just one of the level of volatiles in the environment (see the Reactivity Research Working Group of NARSO - http://www.narsto.org/section.src?SID=10 – for more detail).
Most recent estimates suggest roughly 10% of total VOC’s come directly from Coatings (including Industrial Coatings).