鉴于目前对环境保护和工业安全的重视，来自附近排气口的进气污染问题近年来变得越来越重要。此外，通过再生热交换器从排气中回收能量目前是医疗设施的常见做法，随着燃料成本的持续上升，这种形式的能量回收在其他情况下也可能变得经济合理。进气和排气都需要通过一个热交换器，这可能导致进气和排气口位置之间的间隔缩短，而这反过来只会加剧进气污染问题。 废气再循环引起的三个特别关注领域是健康危害、不良气味和加速腐蚀和降解。目前估计建筑物附近扩散的做法是，在受控风洞条件下，实验测量几个典型建筑物结构周围示踪气体的稀释度，并应用湍流混合的一般物理原理，将结果综合起来，并将其外推到其他感兴趣的情况。本文的目的是以一种形式展示这样一个通用实验程序的结果，该程序将允许设计师从一个近旁的排气口确定建筑物表面上的浓度。 有了这些信息，设计师将能够估计是否确实存在问题，如果确实存在问题，则可以调整排气口位置的允许排放率，从而将入口的排气浓度降低到可接受的水平。本文没有讨论的一个重要问题是，如何修改通风口本身的特性，例如通过改变通风口烟囱的高度或出口的高度，来改变建筑物上某个接收点的浓度。Halitsky和Clarke以及Wilson在ASHRAE RP的最终报告中讨论了这个喷口问题的一些方面- 136，这里提供的数据是其中的一部分。引文:德克萨斯州达拉斯ASHRAE交易会第82卷第1部分研讨会

The problem of air intake contamination from nearby exhaust vents has developed increasingimportance in recent years in light of the emphasis now placed on environmental protection andindustrial safety. Also, energy recovery from exhaust air by regenerative heat exchangers ispresently a common practice for medical facilities and, as fuel costs continue to rise, it isprobable that this form of energy recovery will become economically justifiable in othersituations as well. The need for passing both inlet and exhaust air through a single heatexchanger can dictate a shorter separation between inlet and exhaust vent locations, and thisin turn can only serve to aggravate inlet air contamination problems.Three areas of special concern caused by exhaust gas recirculation are health hazards, undesirable odors, and accelerated corrosion and degradation.The present practice in estimating dispersion near buildings is to measure experimentallythe dilution of tracer gases around a few typical building configurations under controlled windtunnel conditions, and to apply the general physical principles of turbulent mixing togeneralize the results and extrapolate them to other situations of interest. The purpose ofthis paper is to present the results of such a generalized experimental program in a formwhich will allow a designer to determine the concentration on a building surface from a nearbyroof exhaust vent. With this information, the designer will be able to estimate if a problemdoes indeed exist and, if so, to adjust either the allowable emission rate from the vent orits location in such a way as to reduce vent gas concentration at the inlet to acceptablelevels.One important problem which this paper does not discuss is how the characteristics ofthe vent itself can be modified, for example by a change in height of the vent stack or exitvelocity, to alter the concentrations at a receptor point on the buildigg. Some aspects ofthis vent problem are discussed by Halitsky and Clarke, and by Wilson in the final reportof ASHRAE RP-136, of which the data presented here form a part.