Why volatile organic compounds (VOCs) matter in a press room.
The inks used in offset printing are solvent based. Chemicals are used in the water to be optimized for better printing. This results in evaporation.
Petroleum based products produce VOCs. You can smell it! Newspapers are generally printed by coldset web printing and emit an odor. Heatset web presses evaporate the solvents in the ink and dispel them into the atmosphere.
The light at the end of the tunnel is that the offset printing industry is improving. Here are some improvements over the years.
Alcohol has disappeared from the press room.
Years ago, isopropyl alcohol was used in the water system of offset printing presses. It worked great at reducing water tension. The problem was the high level of VOC's used in the process. The vapors were harmful to the worker, not to mention being toxic and flammable. It was inefficient as well. Up to 50% of it evaporated before it even entered the printing press. Suppliers soon learned that additives could be put in the fountain solution to achieve the same effect. Hence press rooms became alcohol free and more environmentally friendly.
But as in many cases, the motivating factors were probably more about economics than the environment. Additives proved to be cheaper. They didn't evaporate before going to the printing press. Insurance premiums went down as there was a reduced risk of fire.
Inks have become vegetable or soy based.
Instead of using petroleum based oils to make inks, ink makers started to use vegetable oils. This trend started in the early 1990's. It took a few years to perfect it, but offset printing ink suppliers developed formulas that could work well with the lithographic process.
VOC's are still released with vegetable based inks. But they are much less lethal than the alternative. Take a look at the graph below. Vegetable based inks began to be used by the offset printing industry in the early 1990s and it brought VOC emission levels down significantly.
Vegetable based inks have less impact on the environment that petroleum inks do. What is more, the source is sustainable and does not fluctuate wildly with oil prices.
Cleaning solvents have improved.
When printing presses are cleaned, a lot of solvent is used. To clean oil based ink, good solvents are needed to dissolve it. The risk here is mostly to the press operator. Manufacturers have removed the harmful elements in these cleaners to protect workers. They don't work as good as the harsher chemicals, but they work.
Printing units also require a wash up from time to time to clean or remove ink. Solvents have been developed that are more friendly to the rubber rollers and the user.
Catalytic converters are used on heatset web presses.
During heatset printing, solvents are evaporated from printing inks by means of heat. These solvents are released into the atmosphere. Beginning in the 1970s and into the 1980s, a catalytic converter was mandated. This was installed after the heatset web press dryer. Solvents would leave the oven and go to the converter and be incinerated at extremely high temperature, literally turning the solvents to ash.
Ventilation is better.
As working conditions improved over the years, good ventilation was installed in pressrooms. Emphysima has been a plague in the printing industry and this has helped alleviate this problem. Note this article on diseases from the offset printing industry.
Conclusion
The offset printing industry has and continues to become more environmentally friendly. But there will always be an impact on the environment as the very nature of using raw materials makes this inevitable.
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