Evaluation of Vehicle Interior Air Quality by Impinger Collection and Subsequent Bioassay Using Cultured Macrophages

Abstract

The long periods of time people often spend inside their automobiles expose them to chemical substances and bioaerosols, such as molds, dust mites, pollens, and pet dander. This study evaluated the health impact of remaining inside a vehicle by combining an impinger that efficiently collects air quality in water from a small space with a bioassay using cultured macrophages. The impinger container was curved to minimize the splashing of water caused by air inflow, and a spray nozzle was attached to its tip to efficiently mix water and air. The water collected to evaluate the interior air quality as well as the reference material CRM28 showed increased expression levels of tumor necrosis factor α (TNFα) and cytochrome P450 1A1 (CYP1A1) in U937 macrophages, demonstrating the utility of impinger collection and subsequent bioassay in evaluating air quality. The water sample collected from an old vehicle induced higher expression of TNFα, CYP1A1, and heme oxygenase-1 than that from a relatively new vehicle. This effect is considered to partially depend on the presence of mold in the vehicular interior space. The method proposed in this study integrating impinger collection with bioassay is suitable for investigating the effects of combined exposure in small spaces such as vehicle interiors.