Evaluation of Settled House Dust Sampling Methods for Chemical, Elemental, and Microbial analyses in Homes

Abstract

Abstract
The study tried to evaluate and develop practical, robust methods for collection of settled house dust and airborne particulates suitable for multi-constituent chemical, elemental, and microbial analyses across contrasting environments.Multiple settled-dust collection techniques (vacuum cleaner bags, petri dishes, ceiling boards, spectrotabs/pin stubs, frisbee and bucket deposition gauges, and manual sweeping) and airborne sampling approaches (Tenax sorbent tubes — passive and pumped, PM10 impactors, P-TRAK ultrafine counter, ICOM CO monitor, Burkard biological sampler) were trialed in homes in north-eastern Nigeria (Harmattan and dust-storm seasons) and the UK. Analytical endpoints included TD/GC/MS for VOCs/SVOCs, ICP-MS for metals, SEM particle characterization, and culture/identification of airborne microbes. The results indicated that Vacuum-cleaner-bag sampling yielded the largest and most versatile bulk dust sample masses (sufficient for TD/GC/MS, ICP-MS, and SEM) and was judged most practical for field conditions, transport, and multi-analytical workflows. Passive petri-dish and deposition gauges provided useful deposition rates but often yielded insufficient mass for multi-method chemical analysis, especially in short deployments or in homes with coarse contamination (rodent excreta). Spectrotabs/pin stubs were suitable for SEM particle morphology when transport integrity was preserved. Tenax diffusive and pumped sampling captured event-specific VOC/SVOC emissions (e.g., cooking, generator use, Harmattan episodes) and combined monitoring (P-TRAK and ICOM) allowed activity-correlated assessment of ultrafine particles and CO. It was also found that Settled dust serves as a practical surrogate for integrated indoor exposure to semi-volatile and particle-bound contaminants; however, sampling method influences particle size fractions collected and thus exposure interpretation (e.g., vacuum bags may underrepresent ultrafine inhalable fractions). For multi-constituent exposure assessment in resource-limited or remote settings, vacuum-bag collection combined with targeted active/passive airborne sampling and microbial impaction provides an efficient, replicable approach. We recommend standardized protocols that prioritize vacuum-bag collection for bulk chemical and elemental analyses, supplemented by passive/pumped Tenax sampling and short-duration instrumentation for event-based airborne metrics; careful sample handling and sieving (e.g., 150 μm) facilitate comparable analyses across sites and seasons.