Quantification of the VOCs released during kiln-drying red oak and white oak lumber

Drying hardwood lumber introduces a potential environmental burden-the release of volatile organic compounds (VOCs) with the hot, humid kiln exhaust. VOCs include lower atmospheric-level ozone precursors that are potentially detrimental to human and environmental health. This project was designed to estimate the amount of VOC emissions released from hardwood lumber during drying in conventional, steam-heated dry kilns. Species investigated included Quercus rubra (red oak), and Quercus alba (white oak). VOC emissions were quantified using a small laboratory oven for lumber drying, a heated sampling line, and a total hydrocarbon analyzer, as outlined in EPA Method 25 A. Species were dried using recommended standard kiln temperature schedule T4. VOC emission data from nine charges of red and white oak were collected. On average, red oak released the largest estimated amount of VOCs, ranging from 0.154 to 0.358 pounds per MBF (data range accounts for variance among charges and for the use of two different calculation methods). Average estimated release for white oak was significantly lower, ranging from 0.058 to 0.227 pounds per MBF. Most of the VOCs were released above 30 percent moisture content.