Gaseous elemental mercury (GEM) concentrations and emissions at legacy contaminated sites represent poorly characterised components of global mercury (Hg) inventories. Here we apply both active (Tekran 2537A) and passive (MerPAS) sampling methods to comprehensively assess GEM concentrations and emissions across four dimensions (three spatial, one temporal) at a legacy contaminated site with elevated soil Hg. Concentrations are measured up to 37.4 (active) and 10.8 (passive) ng m⁻³, which represents enhancements of 23 and 7 above background (1.62 ng m⁻³), respectively. Temporal resolution of the sampling methods defines this difference (active: 5-min; passive: 44 days). Diurnal (active) GEM concentration patterns were highest in contaminated areas at night when low wind speeds compress the boundary layer. Passive sampling substantially improves the spatial characterisation of GEM concentrations both horizontally (highest GEM concentration in areas with elevated soil Hg) and vertically (improved vertical concentration gradient using telescopic sampling towers). Passive sampler deployments were used to generate a GEM emissions estimate (landfill-to-atmosphere) of 1.20.6 kg yr⁻¹ (or 310150 ng m⁻² h⁻¹). This study demonstrates how combining active (strength: temporal assessment) and passive (strength: spatial assessments) sampling improves the evaluation of GEM concentrations and emissions to the atmosphere at Hg contaminated sites across four dimensions.

遗留污染场地的气态元素汞 (GEM) 浓度和排放量代表了全球汞 (Hg) 清单中特征不佳的组成部分。在这里，我们应用主动 (Tekran 2537A) 和被动 (MerPAS) 采样方法，在土壤汞升高的遗留污染场地的四个维度（三个空间，一个时间）上全面评估 GEM 浓度和排放。测量的浓度高达 37.4（主动）和 10.8（被动）ng m ^-3，这表示比背景（1.62 ng m ^-3）， 分别。采样方法的时间分辨率定义了这种差异（主动：5 分钟；被动：44 天）。当低风速压缩边界层时，夜间（活动）GEM 浓度模式在污染区域最高。被动采样大大改善了 GEM 浓度水平（土壤汞含量升高区域的最高 GEM 浓度）和垂直（使用伸缩式采样塔改善垂直浓度梯度）的空间特征。被动采样器部署用于生成 1.20.6 kg yr ^-1（或 310150 ng m ^-2 h ^-1）的 GEM 排放估计（垃圾填埋场到大气））。本研究展示了主动（强度：时间评估）和被动（强度：空间评估）采样如何从四个维度改进对汞污染场地的 GEM 浓度和大气排放的评估。