同样采用ISO/TS 16976 3:2019，其中确定了氧气和二氧化碳浓度限值，以及预计不会造成生理损害的时间长度。为了充分说明对人体生理学的影响，本文件讨论了遇到低分压的高空暴露和涉及高分压条件的水下潜水。还包括呼吸防护装置（RPD）的使用和各种工作速率。 关键词:呼吸防护装置；RPD；生理学人类反应；浓度限值；氧气限制；二氧化碳限制

Identically adopts ISO/TS 16976 3:2019, which identifies oxygen and carbon dioxide concentration limit values and the length of time within which they would not be expected to impose physiological distress. To adequately illustrate the effects on human physiology, this document addresses both high altitude exposures where low partial pressures are encountered and underwater diving, which involves conditions with high partial pressures. The use of respirators and various work rates during which Respiratory Protective Devices (RPDs) can be worn are also included. KEYWORDS: Respiratory protective devices; RPDs; Physiology; Human responses; Concentration limits; Oxygen limitations; Carbon dioxide limitations