Contact: Bob Ratliff
Research at Mississippi State University dealing with various ways to dry wood is yielding some good news for the environment and the state's forest industry.
Almost every use of wood requires drying at some stage of the manufacturing process. As wood dries it gives off emissions of volatile organic compounds that have the potential to harm the environment. While ozone is beneficial in the Earth's upper atmosphere because it absorbs potentially harmful ultra violet light, it is toxic to plants and animals at ground level.
"VOCs contain chemicals that can increase the level of ozone at ground level," said Leonard L. Ingram, MSU professor of forest products. "Their release into the atmosphere is regulated by the Environmental Protection Agency and emission data for VOCs are required for constructing and modifying facilities that dry wood."
To help Mississippi manufacturers adhere to regulations included in the amended 1990 Clean Air Act, Ingram and other scientists with the School of Forest Resources' Forest Products Laboratory are measuring the levels of drying Southern pine lumber. Using lumber samples obtained from mills in the Starkville area, they use a kiln and conventional measuring equipment to obtain data.
Tests of both high-temperature and low-temperature drying methods indicate little difference in emissions, Ingram said.
"Even though the emissions are higher during the early part of the high-temperature process, the totals are about the same for both methods," he added. The scientists have noted a significant difference, however, in emissions from the type of pine lumber being dried.
"Results from these experiments indicate that emissions from drying lumber are not constant," Ingram said. "Factors such as the number of knots and the amount of heartwood in lumber influence the amount created by the drying process."
The increase is not large unless the lumber being dried contains an unusual number of knots or extraordinary amounts of resin or heartwood, he observed.
So far, MSU research indicates that overall levels of emissions are not high enough to have an adverse impact on the atmosphere. Work continues to determine and measure the factors responsible for the varying emission levels.
"Because of the research, we have a better understanding of the compounds being released by the drying process and at what levels they enter the atmosphere," Ingram said. "The results are good news for Mississippi's lumber industry and for anyone concerned about the quality of the air in our state."