Temperature and Humidity Effects on Emissions of Volatile Organic Compounds from Ponderosa Pine Lumber

The total hydrocarbon carbon, or volatile organic compound (VOC), emissions released from ponderosa pine (Pinus ponderosa) were measured as a function of temperature and humidity in the dryer. Flame ionization was used to measure the hydrocarbon concentration of the gas vented from the kiln. The methodology was similar to that of U.S. EPA Method 25A. (U.S. EPA. Method 25A. In 40 Code of Federal Regulations Pt. 60, App. A.; Washington, D.C.) Emissions increased by 34% as the drying temperature increased within the range of 68°C–85°C. An 11°C change in wet-bulb depression did not significantly affect total carbon emissions. Average emissions for a drying cycle, expressed as carbon equivalents, totaled 1.4 g/kg of oven-dry (bone-dry) wood when the lumber was dried from green to 12% moisture content.