Abstract

Ventilation is critical in interpreting indoor air quality (IAQ), yet most IAQ assessments do not report ventilation adequately. Most ventilation assessments use tracer gas tests (TGT) to measure total air change rate (ACH), but currently applied TGTs present three shortcomings: limited comparability between ACH and IAQ data, inadequate substances employed as tracer gases and tendency to bias arising from perfect-mixing assumption. This paper proposes a new TGT approach, employing an alternative tracer gas that is captured/analysed using commercial passive IAQ-samplers and including a careful planning-phase to account for imperfect-mixing. Two substances were selected as potential alternative tracers: 2-butoxyethyl-acetate (EGBEA) and deuterated decane (D-decane). Tracer-source tests were performed in lab, enabling enhancements to the source design. Results indicated RH influence over the emissions rates, and EGBEA’s use as tracer was discarded due to hygroscopy. Further work includes evaluating D-decane’s behaviour under varying conditions and computer-simulating TGTs to study the imperfect-mixing effects.

摘要

通风对于解释室内空气质量 (IAQ) 至关重要，但大多数 IAQ 评估并未充分报告通风。大多数通风评估使用示踪气体测试 (TGT) 来测量总空气变化率 (ACH)，但目前应用的 TGT 存在三个缺点：ACH 和 IAQ 数据之间的可比性有限、用作示踪气体的物质不足，以及由于完美-混合假设。本文提出了一种新的 TGT 方法，采用一种替代示踪气体，该气体使用商业被动 IAQ 采样器进行捕获/分析，并包括一个仔细的规划阶段以解决不完全混合的问题。选择了两种物质作为潜在的替代示踪剂：乙酸 2-丁氧基乙酯 (EGBEA) 和氘代癸烷 (D-癸烷)。示踪源测试在实验室进行，启用对源设计的增强。结果表明 RH 对排放率的影响，并且 EGBEA 作为示踪剂的使用由于吸湿性而被废弃。进一步的工作包括评估 D-癸烷在不同条件下的行为和计算机模拟 TGT 以研究不完美混合效应。