Overview
SIST ISO 4219:1995 is an international standard developed by the International Organization for Standardization (ISO) that specifies the general requirements for sampling equipment used to determine gaseous sulfur compounds in ambient air. Primarily focused on sulfur dioxide (SO₂) and similar reactive sulfur gases, this standard is essential for accurate air quality monitoring. It is designed to be used alongside ISO 4220 and ISO 4221, which provide complementary details on sampling procedures and absorbing solutions.
By defining standardized sampling equipment requirements, ISO 4219 ensures reliable collection, absorption, and analysis of sulfur gases, which is critical for assessing air pollution levels and protecting environmental and human health.
Key Topics
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Scope and Application
Applicable exclusively to ambient air sampling, ISO 4219 specifies equipment requirements for detecting sulfur dioxide and other gaseous sulfur compounds relevant to air quality assessments.
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Sampling Principle
The method involves drawing ambient air through an absorber to trap gaseous sulfur compounds in a liquid medium, enabling subsequent chemical analysis.
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Equipment Components
The standard outlines essential equipment parts, including:
- Air intake (with optional protective funnel against precipitation)
- Connecting tubing (6 to 8 mm internal diameter, airtight, chemically inert)
- Particulate filter and filter holder
- Absorber (absorption bottle) designed for specific analytical methods
- Protection filter to shield gas meters or flow regulators from liquid droplets
- Sampling pump for consistent airflow
- Gas meter or airflow regulator to measure sampled air volume accurately
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Material Requirements
To avoid interference, all components in contact with sulfur gases must be made of chemically inert materials such as PTFE, glass with flexible PVC connectors, polypropylene, or treated plastics. Tubing and filters should not absorb or react with the analytes.
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Installation Guidelines
The equipment should be installed away from pollution sources and obstacles, with an air intake at least 1 meter above any surface and 3 meters from large horizontal areas. Tubing should be arranged to avoid water accumulation and minimize length (