Air‐change rate is an important parameter influencing residential air quality. This article critically assesses the state of knowledge regarding residential air‐change rates, emphasizing periods of normal occupancy. Cumulatively, about 40 prior studies have measured air‐change rates in approximately 10,000 homes using tracer gases, including metabolic CO₂. The central tendency of the air‐change rates determined in these studies is reasonably described as lognormal with a geometric mean of 0.5 h⁻¹ and a geometric standard deviation of 2.0. However, the geometric means of individual studies vary, mainly within the range 0.2–1 h⁻¹. Air‐change rates also vary with time in residences. Factors influencing the air‐change rate include weather (indoor–outdoor temperature difference and wind speed), the leakiness of the building envelope, and, when present, operation of mechanical ventilation systems. Occupancy‐associated factors are also important, including window opening, induced exhaust from flued combustion, and use of heating and cooling systems. Empirical and methodological challenges remain to be effectively addressed. These include clarifying the time variation of air‐change rates in residences during occupancy and understanding the influence of time‐varying air‐change rates on tracer‐gas measurement techniques. Important opportunities are available to improve understanding of air‐change rates and interzonal flows as factors affecting the source‐to‐exposure relationships for indoor air pollutants.

中文翻译：

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住宅换气率：批判性审查

换气率是影响住宅空气质量的重要参数。本文批判性地评估了有关住宅换气率的知识状态，强调了正常入住的时期。累积起来，大约 40 项先前的研究使用示踪气体（包括代谢性 CO _{2 ）}测量了大约 10,000 个家庭的空气变化率。在这些研究中确定的空气变化率的集中趋势被合理地描述为几何平均值为 0.5 h ^-1和几何标准偏差为 2.0 的对数正态分布。然而，个别研究的几何平均值各不相同，主要在 0.2-1 h ^-1范围内. 空气变化率也随着居住时间的推移而变化。影响换气率的因素包括天气（室内外温差和风速）、建筑围护结构的泄漏情况，以及机械通风系统的运行（如果存在）。与占用相关的因素也很重要，包括开窗、烟道燃烧产生的废气以及加热和冷却系统的使用。经验和方法上的挑战仍有待有效解决。其中包括阐明居住期间住宅空气变化率的时间变化，以及了解时间变化的空气变化率对示踪气体测量技术的影响。