5.1 Standards for O₃ in the atmosphere have been promulgated by government authorities to protect the health and welfare of the public (6) and also for the protection of industrial workers (7).

5.2 Although O₃ itself is a toxic material, in ambient air it is primarily the photochemical oxidants formed along with O₃ in polluted air exposed to sunlight that cause smog symptoms such as lachrymation and burning eyes. Ozone is much more easily monitored than these photochemical oxidants and provides a good indication of their concentrations, and it is therefore the substance that is specified in air quality standards and regulations.

1.1 This test method describes the sampling and continuous analysis of ozone (O₃) in the atmosphere at concentrations ranging from 10 to 2000 μg/m³ of O₃ in air (5 ppb(v) to 1 ppm(v)).

1.1.1 The test method is limited to applications by its sensitivity to interferences as described in Section 6. The interference sensitivities may limit its use for ambient and workplace atmospheres.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 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.

1.4 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.