1.1 本试验方法包括手动测定组合二氧化氮（NO 2. )和一氧化氮（NO）含量，总NO x ; 在4到10范围内的大气中 000μg/m 3. （0.002至5 ppm（v））。 1.2 流速为0.4升/分钟时，最大采样周期为60分钟。 1.3 以国际单位制表示的数值应视为标准值。括号中给出的值仅供参考。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。 本标准的用户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。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 两者都没有 2. NO在光化学烟雾形成反应中起重要作用。在足够的浓度下没有 2. 对健康、农业、材料和能见度有害。 5.2 在燃烧过程中，大气氮和氧的结合可能会产生大量的NO；在环境温度下，NO可以转化为NO 2. 通过氧气和其他大气氧化剂。硝酸、硝酸盐、炸药的使用和焊接过程也可能产生二氧化氮。

1.1 This test method covers the manual determination of the combined nitrogen dioxide (NO 2 ) and nitric oxide (NO) content, total NO x ; in the atmosphere in the range from 4 to 10 000 μg/m 3 (0.002 to 5 ppm (v)). 1.2 The maximum sampling period is 60 min at a flow rate of 0.4 L/min. 1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.4 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. 1.5 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 Both NO 2 and NO play an important role in photochemical-smog-forming reactions. In sufficient concentrations NO 2 is deleterious to health, agriculture, materials, and visibility. 5.2 In combustion processes, significant amounts of NO may be produced by combination of atmospheric nitrogen and oxygen; at ambient temperatures, NO can be converted to NO 2 by oxygen and other atmospheric oxidants. Nitrogen dioxide also may be generated from processes involving nitric acid, nitrates, the use of explosives, and welding.