Hazardous Air Pollutants and Volatile Organic Compounds Emitted during Kiln Drying of Southern Pine Lumber to Interior and Export Moisture Specifications

Abstract

The emission levels of hazardous air pollutants (HAPs) from wood kilns are needed to comply with the Clean Air Act. Softwood lumber, including southern pine (Pinus taeda, Pinus palustris, Pinus echinata, and Pinus elliottii), is considered kiln dry when the wood moisture content reaches below 19 percent, but it is sometimes overdried or dried to 8 percent moisture content for export or interior applications. To study HAP emissions when drying to 8 percent moisture content, green lumber was obtained from a local mill, and 12 charges were kiln dried using three schedules: a 99°C elevated schedule and 116°C and 127°C high-temperature schedules. Methanol and formaldehyde were collected and analyzed using the National Council for Air and Stream Improvement (NCASI) 98.01 method, “Chilled Impinger Method for Use at Wood Products Mills to Measure Formaldehyde, Methanol, and Phenol,” where formaldehyde was analyzed via spectrophotometry using acetylacetone and methanol was analyzed via gas chromatography with a fl...