ISO 10313:1993

Overview

ISO 10313:1993 - Ambient air: Determination of the mass concentration of ozone - Chemiluminescence method specifies a standardized chemiluminescence technique for measuring ozone in ambient air. The method draws a continuous, constant-flow air sample through a particle filter into a reaction chamber where it mixes with excess ethylene. Ozone + ethylene react instantly to emit visible light (maximum near 400 nm); the emitted light, measured by a photomultiplier, is proportional to ozone concentration. The standard applies to mass concentrations from 2 µg/m³ to 10 mg/m³ at reference conditions (25 °C, 101.3 kPa).

Key topics and technical requirements

• Measurement principle: chemiluminescence (ozone + ethylene → visible emission ≈ 400 nm) with photomultiplier detection.
• Calibration: ultraviolet (UV) photometry (primary method) using a low‑pressure mercury lamp (253.7 nm) is specified for primary calibration. Transfer standards may be used if annually traceable to the UV standard.
• Sampling system:
  • Particle filter (ozone‑inert materials such as fluorocarbon polymer) to prevent particulate-induced ozone loss or optical scattering.
  • Sampling line of ozone‑inert material (glass or fluorocarbon polymer) kept as short as possible; recommended residence time <0.5 s (routine up to 5 s).
• Reagents & gases:
  • Ethylene of minimum purity 99.5% for the chemiluminescent reaction.
  • Zero air used for calibration must be free of ozone and NOx; if synthetic air is used its oxygen content should be within ±2% of 20.9%.
• Apparatus: chemiluminescence analyser with reaction chamber, photomultiplier, signal processing electronics, flowmeters and pumps; ozone generator and UV photometer for calibration systems.
• Performance & quality:
  • Overall precision for generation and UV-photometric measurement better than ±5% (UV-photometric calibrations can be within ±1% with careful operation).
  • Recommended multipoint calibration every 3 months; routine zero/span checks (weekly).
• Safety notes: Ethylene is flammable (lower explosive limit noted in the standard). Ozone is toxic - excess exhaust must be vented or scrubbed.

Practical applications

• Ambient air quality monitoring networks for regulatory compliance and trend assessment.
• Field and laboratory ozone measurement, instrument validation and intercomparisons.
• Calibration and service laboratories using transfer standards or primary UV photometric systems.
• Research studies requiring accurate ozone concentration data (health, atmospheric chemistry, exposure assessment).

Who uses this standard

• Environmental and air quality monitoring agencies
• Calibration laboratories and instrument manufacturers
• Field technicians and researchers conducting ambient ozone measurements
• Quality managers establishing traceable ozone measurement programs

Related standards

• Other ISO air‑quality standards and guidance produced by ISO/TC 146 (Air quality, Sub‑Committee SC 3 - Ambient atmospheres) and methods referenced for calibration and zero‑air generation (see ISO 10313 annexes).