Combatting climate change through reductions in emissions of carbon dioxide (CO2) remains a matter of primary importance in Europe. But mounting anxieties about poor air quality are beginning to overshadow concerns related to the dangers of global warming.
Coatings which promote lower levels of CO2 and other global warming gases tend also to help keep the air clean. As a result these coatings are seen as having a two-pronged advantage.
Politicians and NGOs in Europe have been pressing for decreases in CO2 emissions and in air pollutants to be given an equal priority.
”There is little doubt that terrible levels of air pollution being suffered by people in many countries and cities around the world is finally pushing this issue up the political agenda,” said James Thornton, chief executive of ClientEarth, London, an international environmental lawyers group. “This is a very real public health emergency. It is simply not acceptable that pollution is not being tackled as a major health issue. If the water we drink was causing so many early deaths, we’d take immediate and urgent steps. The same should happen for the air we breathe.”
While CO2 levels have been falling in the region, air pollution figures in some of Europe’s major cities have been worsening due mainly to contaminants from automobile and truck fuels and from industrial plants.
Statistics from the World Health Organisation (WHO) show that air pollution in Europe could be causing as many as 400,000 early deaths from respiratory conditions, heart disease and certain cancers.
These are being linked to impurities in street air such as particulate matter (PM), sulphur dioxide (SO2), nitrogen oxides (NOx), ammonium ( NH3), ozone and carbon monoxide (CO) and CO2. Some of these and other contaminants are fouling the air inside homes, offices and other buildings.
Coatings producers are having to concentrate more on the development of formulations which are free from chemicals posing risks to public health through air pollution.
These priorities were evident at the recent European Coatings Show at Nuremberg, Germany, where exhibitors were giving a high profile to issues of air quality.
“Consumer perception of eco-friendliness is changing the behaviour of the paints industry more and more,” explained Daniet Bruenink, director global marketing for decorative paints at Evonik, the German-based additives producers. “Paints are being identified as a source of (for example) indoor air pollution and customers are demanding healthy and sustainable solutions.”
Formulators are seeking ways of giving coatings additional functionalities such as methods of keeping surfaces clean because leaching of dirt can contaminate air.
Silicone-based polymers with hydrophobic and oleophobic properties can provide easy-to-clean effects that ensure dust, oil pen marks and wine and coffee spills can be easily removed from coated substrates, according to Altana’s Byk Additives & Instruments business.
There is also a robust demand for paints with low odor, which is a quality inherent in paints with low emissions of volatile organic compounds or without any VOC discharge.
In fact, across much of Europe there have been strong increases in sales of coatings and ingredients with low emissions of VOCs or their complete absence. This is perhaps evidence of a combination of concerns about both climate change and poor air quality.
A survey of people attending the ECS Congress found that the highest proportion – 20 percent – considered that VOC emissions was the most important current regulatory issue.
Companies have been reporting sudden surges in sales for their low VOC or emission-free products, some of which have been on the market for a relatively long time.
“Demand levels at the moment show a major trend in favour of low emissions paints,” saie Tomas Espana, Celanese’s acetyl chain account manager in Europe. One of Celanese’s main low-emissions products in Europe is a vinyl-acetate-ethylene (VAE) dispersion with low emissions both of VOCs and also semi-VOCs (SVOCs) which because of their slow evaporation produce emissions over a longer period of time in building interiors.
Sales of low emissions products have been boosted in Europe by stipulations by national governments that coatings carry eco-labelling indicated their levels of VOCs or even SVOCs.
“The rules on eco-labeling have changed the market in some countries for household items like furniture and other products with coatings whose products can affect interior air quality,” explained Espana. “If your product doesn’t qualify for a an eco-label because its coatings breach an emissions threshold it will not get into some markets.”
Another clean-air product which also appears to be enjoying a suddent rise in sales is photocatalytic paint with the catalytic ingredient mainly being titanium dioxide. Most TiO2 producers in the European market supply grades of the pigment which are photocatalytic.
They accelerate the degradation of organic pollutants such as NOx, which are precursors to the formation of the particulate matter regarded as the most hazardous of contaminants to human health.
“Demand for our TiO2-based photocatalysts are going up at a double-digit rate,” said Heinz-Christian Krempels, technical manager, pigments and TiO2 specialities, Kronos International, Leverkusen, Germany. “The growth is fastest in Europe where the photocatalysts are being applied in paints for exterior use such as on pavements, walls and roofs but they are also being used in interior coatings as well.”
Studies on the effectiveness of TiO2 photocatalysts in tackling air pollution have had mixed results. The UK’s Air Quality Expert Group (AQEG) concluded in a report last year they did not achieve “significant reductions” in nitrogen dioxide concentrations mainly because large volumes of air would have to interact with the coated surface.
However technologies which increase the catalytic potential of TiO2 may be more effective. The TiO2 photocatalysts of Kronos , for example, are coated with a carbon dopant. This results in a 4 percent reduction in the air polluting emissions from motor vehicles, which Kronos claims in higher than that of other TiO2 photocatalysts.
New dopant technologies on both TiO2 and other substances could give photocatalytic coatings even greater potential in the fight against air pollution. They are an example of new opportunities being opened up to coatings producers by the desire among consumers for cleaner air.