Laboratory air quality and room ventilation rates: An update

This report extends previously published empirical testing of laboratory air quality at varying room air change per hour (ACH) rates under controlled releases of organic solvents. Additional testing was performed after modifying the ventilation controls to enable reliable operations at room ventilation rates as low as 2 ACH, and with additional solvents for some test conditions. The accumulation, peak concentration, and clearance of airborne contaminants continued to be inversely proportional to the overall room ACH rate, demonstrating that low laboratory ventilation rates require exceptionally long times to clear.