1.1 本指南描述了室内二氧化碳（CO 2. )浓度对室内空气质量（IAQ）和建筑物通风的影响。 1.2 本指南包含有关室内CO对健康、舒适性和性能影响的背景信息 2. 暴露，以及室内CO 2. 各种标准和法规中包含的限制。 1.3 本指南描述了CO的估计 2. 作为性别、年龄、体重和体育活动水平的函数的人的生成率。 1.4 本指南描述了CO的关系 2. 到IAQ，包括CO如何 2. 与人体气味的感知有关，CO应用的限制 2. 作为IAQ的一个指标，以及CO的关系 2. 暴露于传染性气溶胶的风险。 1.5 本指南介绍了CO 2. 浓度测量可用于评估建筑物通风，包括质量平衡分析以确定空气处理器处的室外空气吸入百分比，示踪气体衰变测量以估计整个建筑物的空气变化率，以及在平衡时使用恒定注入示踪气体技术来估计整个建筑物空气变化率。 1.6 本指南讨论了浓度测量问题，如校准和传感器位置，以及连续的室内浓度监测，但不包括任何应用的具体测试方法。 1.7 本指南讨论了室内CO的使用 2. 需求控制通风（DCV）的浓度，但不包含详细的应用指南。 1.8 单位-- 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.9 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.10 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 室内CO 2. 多年来，浓度一直被用作室内空气质量的指标，包括对室内CO的适当和不适当解释 2. 浓度 ( 1. ) . 5. 适当的用途包括根据人体气味感知来估计居住者的预期舒适度，研究居住模式，调查与居住者活动相关的污染物水平，以及筛查通风率的充分性。不适当的用途包括根据室内CO估算每人的室外空气通风率 2. 未正确应用质量平衡方法的浓度，包括验证这些方法所基于的假设，以及使用室内CO 2. 浓度作为室内空气质量的综合指标。 5.2 室外空气通风率影响建筑物中的空气污染物水平和居住者对室内环境可接受性的感知。 建筑规范和标准中规定了室外空气通风的最低速率，例如非住宅建筑的ASHRAE标准62.1。室外空气通风率是否符合相关规范和标准，通常作为室内空气质量调查和建筑能源审计的一部分进行评估。建筑物的室外空气通风率取决于围护结构空气泄漏部位的大小和分布、风和温度引起的压差、机械系统的设计和运行以及居住者的行为。 5.3 CO的测量 2. 浓度已被用于估计室外空气的通风率。本指南中称为平衡分析的一种常见方法是基于CO的稳态单区质量平衡 2. 但经常很少或根本没有讨论其局限性和所基于的假设。 结果，这项技术被滥用和误解了。然而，当平衡分析所基于的假设是有效的，并且该技术应用得当时，它可以对室外空气通风率进行可靠的估计。 5.4 室内CO 2. 如果使用得当，可以使用浓度来确定建筑物通风的其他方面。例如，通过在空气处理器处应用质量平衡，可以基于CO来确定供应气流中的室外空气进气百分比 2. 供应、返回和室外空气中的浓度。该百分比可以乘以空气处理器的供应气流速率，以产生空气处理器的室外空气吸入速率。此外，室内CO的衰变 2. 可以在居住者离开后监测建筑物中的浓度，以确定建筑物的室外空气变化率。 5.5 室内CO的连续监测 2. 浓度可用于研究通风系统性能、室外空气质量和建筑占用模式的某些方面。持续监测已用于评估整体室内空气质量。然而，充其量室内CO 2. 浓度可以作为室内污染物排放速率的指标，排放速率取决于居住者的数量。考虑到许多污染物不取决于居住者的数量，例如从户外进入的污染物以及材料、家具、清洁剂和个人护理产品排放的污染物，它们不能作为室内空气质量的综合指标。 5.6 室内CO 2. 多个组织已经颁布了法规和指导价值观，但这些价值观并不一定包括限制的理由。它们可能基于CO 2. 作为通风率的指标，或CO对健康和性能的影响 2. 面临有一些证据表明，在常见的室内CO条件下，后一种影响 2. 浓度，但并不一致，需要进一步研究。 5.7 室内CO的测量 2. 浓度正在被宣传为指导中的通风指标，以降低新冠肺炎大流行期间感染性气溶胶暴露的风险。在大多数情况下，这种应用是基于估计每人室外空气通风率的平衡方法，尽管这些值的技术基础并不总是得到很好的解释。在其他情况下，CO 2. 被提议作为暴露于其他居住者排放的传染性气溶胶和相关疾病风险的指标，尽管此类应用涉及许多关于空气中CO的命运和运输之间相似性的假设 2. 以及传染性气溶胶。 5.8 一氧化碳对健康和性能的影响 2. 面临 5.8.1 室内CO 2. 自18世纪以来，在通风和室内空气质量的讨论中，浓度一直很突出 th Antoine Lavoisier提出CO 2. 室内空气“不好”的原因是积聚而不是缺氧。大约一百年后，Max Joseph von Pettenkofer提出，来自人类居住者的生物污染物是室内不良空气的来源，而不是一氧化碳 2. ( 2. ) 从20世纪30年代开始的最近的研究表明，室内CO 2. 中讨论的与人类生物排泄物相关的气味强度的居住者感知浓度 7.1 ( 3. ) . 5.8.2 室内CO 2. 当室外空气通风率相对于居住者的数量较低时，在具有高达约3000ppm（v）的偏移的非工业空间中的浓度通常在1000ppm（v）的数量级。 一氧化碳 2. 在这些水平下被认为是无毒的，每周工作40小时的职业限值为5000 ppm（v） ( 4. ) 短期（15分钟）暴露为30000 ppm（v） ( 5. ) 这些和其他限制在中进行了更详细的讨论 5.9 .已经对一氧化碳的影响进行了毒理学研究 2. 人类和动物的暴露，包括呼吸、神经、生殖和心血管影响，这些研究表明，浓度为数万甚至数十万ppm（v）时会产生影响。 5.8.3 20世纪80年代及以后的研究结果发现，室内CO 2. 水平和居住者健康症状（在某些情况下称为病态建筑综合征症状）以及旷课。这些研究经常强调浓度超过1000 ppm（v）时症状患病率和缺勤率的增加。然而，这些研究并没有控制其他污染物，这些污染物可能与导致CO升高的人均通气率降低有关 2. 浓度。因此，当CO升高时 2. 与症状和缺勤相关的其他化学物质或生物制剂浓度升高可能是实际原因。最近的研究已经检验了纯CO的影响 2. 浓度为600ppm（v）至5000ppm（v）对认知表现的影响。例如，一些研究表明，在1000 ppm（v）的浓度下，认知功能会降低，而其他研究则没有。基于这些不一致性，需要进一步调查，包括研究这些影响的潜在机制。 5.9 室内CO 2. 现行标准和建筑法规中的限制: 5.9.1 一些组织已经发布了室内CO 2. 多年来的浓度限制，尽管在许多情况下，没有记录限制的理由。在某些情况下，公布的限额是基于CO 2. 是人均室外空气通风率低以及相应暴露于其他室内空气浓度升高的指标- 产生的污染物。室内环境质量指南在线数据库 6. 包含室内CO的几个国家和组织限制 2. 范围从高于室外浓度约500ppm（v）到职业环境的高得多的极限。加拿大住宅室内CO 2. 该指南还包含一个室内CO指南和标准表 2. 浓度 ( 6. ) .一氧化碳的职业接触限值 2. 在美国，8小时时间加权平均值为5000 ppm（v） ( 4. ) 和30000 ppm（v）暴露15分钟 ( 5. ) 然而，这些限制对一般室内环境的适用性有限，因为它们旨在将暴露控制在保护工人健康的水平，而不是旨在消除所有影响，如难闻的气味和刺激，也不是基于对涵盖不同年龄和健康状况的普通人群的考虑。 5.9.2 最近，为了应对新冠肺炎大流行，额外的CO 2. 限制已作为建议和某些情况下的要求颁布。例如，美国疾病控制和预防中心 ( 7. ) ，欧洲供暖、通风和空调协会联合会 ( 8. ) 在欧洲；环境建模小组和行为科学流行病洞察小组 ( 9 ) 在英国已经发布了建议的室内CO 2. 限制，以评估用于感染控制的通气率的充分性，并在这些参考文献中详细讨论了这些建议的技术依据。比利时联邦政府发布了强制性CO 2. 浓度限值 ( 10 ) 室内CO的关系 2. 传染性气溶胶暴露的浓度在中进行了讨论 7.3 . 5.9.3 在这些室内CO的背景下 2. 限制，值得注意的是，ASHRAE标准62.1《通风和可接受的室内空气质量》没有包含此类限制，自1989年以来也没有。该标准的2016年版本在一个不属于该标准的信息性附录中指出，对于每人7.5 L/s的室外空气通风率，稳态室内CO 2. 浓度将比室外高出约700ppm（v），将室内浓度保持在或低于这一水平“将表明进入空间的绝大多数游客对人类生物排泄物（体味）感到满意” 2. 在中讨论了生物流的浓度和感知 7.1 虽然ASHRAE标准62.1不包含室内CO 2. 它确实“规定了最低通风率和其他措施，旨在提供人类居住者可接受的室内空气质量，并将不良健康影响降至最低。 ”

1.1 This guide describes the relationship of indoor carbon dioxide (CO 2 ) concentrations to indoor air quality (IAQ) and building ventilation. 1.2 This guide contains background information on the health, comfort, and performance impacts of indoor CO 2 exposure, as well as indoor CO 2 limits contained in various standards and regulations. 1.3 This guide describes the estimation of CO 2 generation rates from people as a function of sex, age, body mass, and level of physical activity. 1.4 This guide describes the relationship of CO 2 to IAQ, including how CO 2 relates to the perception of human body odor, limitations on the application of CO 2 as a metric of IAQ, and the relationship of CO 2 to the risk of infectious aerosol exposure. 1.5 This guide describes how CO 2 concentration measurements can be used to evaluate building ventilation including mass balance analysis to determine the percent outdoor air intake at an air handler, tracer gas decay measurements to estimate whole building air change rates, and use of the constant injection tracer gas technique at equilibrium to estimate whole building air change rates. 1.6 This guide discusses concentration measurement issues, such as calibration and sensor location, and continuous indoor concentration monitoring but does not include specific test methods for either application. 1.7 This guide discusses the use of indoor CO 2 concentrations for demand control ventilation (DCV) but does not contain detailed application guidance. 1.8 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Indoor CO 2 concentrations have been used as indicators of IAQ for many years, involving both appropriate and inappropriate interpretations of indoor CO 2 concentrations ( 1 ) . 5 Appropriate uses include estimating expected levels of occupant comfort in terms of human body odor perception, studying occupancy patterns, investigating the levels of contaminants that are related to occupant activity, and screening for the sufficiency of ventilation rates. Inappropriate uses include estimating outdoor air ventilation rates per person from indoor CO 2 concentrations without properly applying mass balance methods, including verifying the assumptions upon which those methods are based, and using indoor CO 2 concentrations as a comprehensive indicator of IAQ. 5.2 Outdoor air ventilation rates affect airborne contaminant levels in buildings and occupant perceptions of the acceptability of the indoor environment. Minimum rates of outdoor air ventilation are specified in building codes and standards, for example, ASHRAE Standard 62.1 for non-residential buildings. Compliance of outdoor air ventilation rates with relevant codes and standards is often assessed as part of IAQ investigations and energy audits in buildings. Outdoor air ventilation rates of a building depend on the size and distribution of envelope air leakage sites, pressure differences induced by wind and temperature, mechanical system design and operation, and occupant behavior. 5.3 The measurement of CO 2 concentrations has been used to estimate outdoor air ventilation rates. One common approach, referred to in this guide as equilibrium analysis, is based on a steady-state, single-zone mass balance of CO 2 in the building but is too often presented with little or no discussion of its limitations and the assumptions on which it is based. As a result, the technique has been misused and misinterpreted. However, when the assumptions upon which equilibrium analysis is based are valid and the technique is applied properly, it can yield reliable estimates of outdoor air ventilation rates. 5.4 Indoor CO 2 concentrations can be used to determine other aspects of building ventilation when used properly. For example, by applying a mass balance at an air handler, the percent outdoor air intake in the supply airstream can be determined based on the CO 2 concentrations in the supply, return, and outdoor air. This percentage can be multiplied by the supply airflow rate of the air handler to yield the outdoor air intake rate of the air handler. In addition, the decay of indoor CO 2 concentrations can be monitored in a building after the occupants have left to determine the outdoor air change rate of the building. 5.5 Continuous monitoring of indoor CO 2 concentrations can be used to study some aspects of ventilation system performance, the quality of outdoor air, and building occupancy patterns. Continuous monitoring has been used to evaluate overall IAQ. However, at best, indoor CO 2 concentrations can serve as indicators of indoor contaminants emitted at rates that depend on the number of occupants. They do not serve as a comprehensive indicator of IAQ given the many contaminants that do not depend on the number of occupants, such as those entering from outdoors and those emitted by materials, furnishings, cleaning agents, and personal care products. 5.6 Indoor CO 2 regulations and guideline values have been promulgated by multiple organizations, however the justifications for the limits are not necessarily included with the values. They are likely based on either CO 2 as an indicator of ventilation rates, or on the health and performance impacts of CO 2 exposure. There is some evidence of the latter impacts at commonly observed indoor CO 2 concentrations, but it is not consistent and requires further study. 5.7 Measurement of indoor CO 2 concentrations is being promoted as a ventilation indicator in guidance to reduce the risk of infectious aerosol exposure in response to the COVID-19 pandemic. In most cases, this application is based on the equilibrium approach to estimating outdoor air ventilation rates per person, although the technical basis for the values is not always well explained. In other cases, CO 2 is proposed as an indicator of exposure to infectious aerosols emitted by other occupants and the associated risk of disease, although such applications involve numerous assumptions regarding the similarity between the fate and transport of airborne CO 2 and infectious aerosols. 5.8 Health and Performance Impacts of CO 2 Exposure: 5.8.1 Indoor CO 2 concentrations have been prominent in discussions of ventilation and IAQ since the 18 th century when Antoine Lavoisier suggested that CO 2 build-up rather than oxygen depletion was responsible for “bad air” indoors. About one hundred years later, Max Joseph von Pettenkofer suggested that biological contaminants from human occupants were the source of bad indoor air, not CO 2 ( 2 ) . More recent research, starting in the 1930s, showed the relationship of indoor CO 2 concentrations to occupant perceptions of odor intensity associated with human bioeffluents as discussed in 7.1 ( 3 ) . 5.8.2 Indoor CO 2 concentrations are typically on the order of 1000 ppm(v) in non-industrial spaces with excursions up to about 3000 ppm(v) when outdoor air ventilation rates are low relative to the number of occupants. CO 2 is considered to be non-toxic at these levels, with occupational limits of 5000 ppm(v) over a 40 h workweek ( 4 ) and 30 000 ppm(v) for short term (15 min) exposures ( 5 ) . These and other limits are discussed in more detail in 5.9 . Toxicological studies have been conducted on the effects of CO 2 exposure in humans and animals, including respiratory, neurologic, reproductive, and cardiovascular impacts, with these studies showing impacts at concentrations of tens of thousands or even hundreds of thousands of ppm(v). 5.8.3 Research results from the 1980s and later found associations between indoor CO 2 levels and occupant health symptoms (in some cases referred to as sick building syndrome symptoms) and school absenteeism. These studies often highlight increases in symptom prevalence and absenteeism at concentrations above 1000 ppm(v). However, these studies did not control for other contaminants that were presumably elevated in association with the reduced per person ventilation rates that led to elevated CO 2 concentrations. Thus, while elevated CO 2 correlated with symptoms and absenteeism, elevated concentrations of other chemicals or biological agents may be the actual cause. More recent studies have examined the impacts of pure CO 2 at concentrations from 600 ppm(v) to 5000 ppm(v) on cognitive performance. For example, some studies have shown reduced cognitive function at concentrations on the order of 1000 ppm(v), while others have not. Based on these inconsistencies, further investigation is merited, including research on potential mechanisms for these impacts. 5.9 Indoor CO 2 Limits in Existing Standards and Building Regulations: 5.9.1 Several organizations have issued indoor CO 2 concentration limits over the years, though in many cases the rationales for the limits are not documented. In some cases, published limits are based on CO 2 being an indicator of low outdoor air ventilation rates per person and the corresponding exposure to elevated concentrations of other indoor-generated contaminants. An online database of indoor environmental quality guidelines 6 contains several national and organizational limits for indoor CO 2 ranging from about 500 ppm(v) above outdoor concentrations to much higher limits for occupational environments. A Canadian residential indoor CO 2 guideline also contains a table of guidelines and standards for indoor CO 2 concentrations ( 6 ) . Occupational exposure limits for CO 2 in the U.S. are 5000 ppm(v) for an 8 h time weighted average ( 4 ) and 30 000 ppm(v) for a 15 min exposure ( 5 ) . However, these limits are of limited applicability to general indoor environments as they are intended to control exposure to levels that protect worker health, they are not intended to eliminate all effects such as unpleasant odors and irritation and are not based on consideration of the general population that covers a range of age and health status. 5.9.2 More recently, in response to the COVID-19 pandemic, additional CO 2 limits have been promulgated as recommendations and in some cases requirements. For example, the U.S. Centers for Disease Control and Prevention ( 7 ) , the Federation of European Heating, Ventilation and Air Conditioning Associations ( 8 ) in Europe; and Environmental Modelling Group and Scientific Pandemic Insights Group on Behaviours ( 9 ) in the United Kingdom have issued recommended indoor CO 2 limits to assess the adequacy of ventilation rates for infection control, with technical rationales for these recommendations discussed in these references to varying degrees of detail. The Belgian Federal Government has issued mandated CO 2 concentration limits ( 10 ) . The relationship of indoor CO 2 concentrations to infectious aerosol exposure are discussed in 7.3 . 5.9.3 In the context of these indoor CO 2 limits, it is important to note that ASHRAE Standard 62.1, Ventilation and Acceptable Indoor Air Quality, contains no such limit and has not since 1989. The 2016 version of the standard did note, in an informative appendix that is not part of the standard, that for an outdoor air ventilation rate of 7.5 L/s per person, the steady-state indoor CO 2 concentration will be about 700 ppm(v) above outdoors and that maintaining indoor concentrations at or below this level “will indicate that a substantial majority of visitors entering a space will be satisfied with respect to human bioeffluents (body odor).” The relationship between indoor CO 2 concentrations and the perception of bioeffluents is discussed in 7.1 . While ASHRAE Standard 62.1 does not contain indoor CO 2 limits, it does “specify minimum ventilation rates and other measures intended to provide IAQ that is acceptable to human occupants and that minimizes adverse health effects.”