Sulfur Dioxide (SO2) Detectors

Which sulfur dioxide (SO2) detector should you buy in 2026?

Short answer: For sulfur dioxide, use a dedicated SO2 analyzer such as the Forensics SO2 Analyzer (0-20 ppm) — for refineries, pulp & paper, smelting and combustion sources, where SO2 is the toxic hazard a 4-gas monitor doesn’t cover.

Sulfur dioxide (SO2) is a pungent, toxic gas from burning sulfur-containing fuels, smelting, pulp and paper, and food preservation. It is acutely irritating to the respiratory tract. SO2 detection uses an electrochemical sensor and a low range to match its strict exposure limits.

This is a gas-type collection under the Gas Detectors hub. Match the gas to the right form factor: Portable Gas Detectors for carried checks, Personal & Wearable Gas Detectors for single-worker exposure, Fixed Gas Detection Systems for continuous plant monitoring, Area & Transportable Gas Monitors for job-site zones, and Gas Leak Detectors to pinpoint a leak source.

Detectors in this collection

This collection gathers SO2 instruments. The Forensics SO2 Analyzer reads 0-20 ppm with a built-in pump and probe for surveys and remote sampling. For the four atmospheric gases alongside SO2, pair it with a unit from Portable Gas Detectors.

Editor’s pick — a low-range handheld SO2 analyzer with a pump
The Forensics SO2 Analyzer pairs a low 0-20 ppm range with pump-and-probe sampling and NIST calibration — matched to SO2’s strict limits. As an Amazon Associate, WC Safety earns from qualifying purchases.

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How to choose a sulfur dioxide detector

Low range matters

SO2 has strict exposure limits, so choose a low, high-resolution range (often 0-20 ppm) with low alarm set points.

Pump and probe

A pump and probe let you survey combustion sources and sample remotely.

Placement

Sulfur dioxide is heavier than air, so mount fixed detectors low and check low-lying and enclosed areas first.

Sulfur Dioxide (SO2) hazard, exposure limits & placement

The OSHA Permissible Exposure Limit for sulfur dioxide is 5 ppm as an 8-hour TWA; ACGIH lists a much lower STEL. Sulfur dioxide is heavier than air, so mount fixed detectors low and check low-lying and enclosed areas first, so it collects in low areas near combustion sources. Set low alarm points and confirm current limits with OSHA's annotated PEL tables.

Frequently asked questions

What detects sulfur dioxide?

A dedicated SO2 detector with an electrochemical sensor — a standard 4-gas monitor does not cover SO2.

What is the OSHA limit for sulfur dioxide?

5 ppm as an 8-hour TWA per the OSHA PEL; ACGIH lists a lower short-term limit.

Where is SO2 detection used?

Refineries and combustion sources, pulp and paper mills, metal smelting, and food/beverage operations using SO2 as a preservative.

Why is the range only 0-20 ppm?

SO2 has strict exposure limits, so a low, high-resolution range is appropriate for monitoring around the relevant ppm levels.

Is SO2 heavier than air?

Yes — sulfur dioxide is heavier than air and collects in low-lying areas near sources.

Do SO2 sensors need calibration?

Yes — bump-test with SO2 calibration gas and recalibrate on schedule; electrochemical SO2 sensors are consumables.

Can I use it for confined-space entry?

SO2 is one hazard; entry also needs O2, combustible and toxic testing with a portable 4-gas instrument.

Portable or fixed SO2 detection?

Handheld units cover surveys and exposure; fixed SO2 detection exists for continuous coverage of combustion areas. See Fixed Gas Detection Systems.

What does the Forensics SO2 Analyzer cover?

The Forensics SO2 Analyzer reads 0-20 ppm with a pump and probe, NIST-calibrated.

How dangerous is SO2 exposure?

SO2 is acutely irritating to the eyes and respiratory tract even at low ppm, which is why low alarm set points matter.