Impact of Wildfire Smoke Age and Filter Smoke Exposure on Air Cleaner Effectiveness

RYAN BIXLER, Brett Stinson, Baorong Luo, Elliott Gall, Portland State University

     Abstract Number: 263
     Working Group: Indoor Aerosols

Abstract
Wildfires are increasing in frequency and intensity in the U.S., emitting substantial quantities of air pollution. During extreme wildfire smoke events, indoor environments are challenged by particulate and gas-phase air pollution orders of magnitude higher than non-wildfire smoke periods. Air cleaning is an essential tool to address indoor exposures to wildfire smoke, though better understanding of air cleaner performance under a persistent, elevated smoke challenge condition is needed. In this work, we describe a novel experimental device that enables control over the generation of wildfire smoke proxies suitable for laboratory environments. The device is a glass tube furnace with ring heater attached to a linear actuator; this device enables control over burn temperature, fuel feed rate, fuel type, and combustion gas type and flowrate. First, this device will be programmed and evaluated, aiming to create persistent conditions representative of an indoor space challenged by elevated smoke. Several common air cleaners will be evaluated with pull-down tests to determine particle clean air delivery rates (CADR) at regular intervals over a ~1-week period when challenged by high “fresh” smoke levels. Next, we will explore the impact of smoke age on air cleaner efficiency by comparing CADRs determined when an air cleaner is exposed to fresh smoke vs. smoke aged in the dark between 2-48 hours. Finally, we will explore the impact light and oxidant addition (ozone) on the evolution of fresh wildfire smoke in the chamber and its impact on air cleaner CADR. The data from this study will contribute to an improved understanding of how to generate repeatable proxies of wildfire smoke for controlled lab testing and how changes in smoke challenge may yield impacts on measurements of air cleaner performance.