How to Choose a Formaldehyde Detector: Electrochemical vs. Semiconductor Sensors

Formaldehyde (HCHO) is a primary harmful pollutant from indoor renovations. Long-term exposure can lead to respiratory diseases and even leukemia. Choosing a reliable formaldehyde detector is critical for both homes and businesses. This article compares two mainstream sensor technologies to help users make an informed decision.

## Electrochemical Sensors: Professional-Grade Accuracy

The electrochemical sensor generates a current through the oxidation-reduction reaction of formaldehyde on the electrode surface. The current magnitude is proportional to the formaldehyde concentration.

Advantages: High accuracy (resolution up to 0.01 mg/m³), high selectivity (unaffected by alcohol, perfume, etc.), and wide linear range (0-5 mg/m³).

Drawbacks: Higher cost, sensor lifespan of 2-3 years before replacement required, and need for regular calibration.

Application Scenarios: Professional indoor air quality testing, CMA-accredited laboratories, and corporate occupational health assessments. Le Xin Electronic Technology (Baiantu)'s formaldehyde detector features imported electrochemical sensors and meets the accuracy requirements of GB/T 18883.

Semiconductor Sensors: Consumer-Grade Solutions

Semiconductor sensors operate on the principle that formaldehyde gas alters the electrical resistance of semiconductor materials.

Advantages: Low cost, compact size, and long lifespan (over 5 years).

Drawbacks: Lower accuracy (typical resolution 0.1 mg/m³), susceptibility to interference from other gases (e.g., alcohol, cooking fumes), and narrow linear range.

Use Case: Daily home monitoring and rough indoor air quality assessment. Not suitable for legal arbitration or professional testing.

National Standard Limits

GB/T 18883-2022 "Indoor Air Quality Standard": Formaldehyde limit is 0.08 mg/m³ (1-hour average).

GB 50325-2020 "Standard for Control of Indoor Environmental Pollution in Civil Building Engineering": Formaldehyde limit for Class I civil buildings (residential, hospitals, schools) is 0.07 mg/m³.

Buying Guide

For home use and rough monitoring: a semiconductor sensor is sufficient, priced at 200-500 yuan.

Professional testing and legal arbitration: Electrochemical sensors are required. Price: 1000-5000 CNY.

Enterprise Procurement & Occupational Health: Choose electrochemical detectors with CMA calibration certificates.

Important: Regardless of the sensor type, seal the newly renovated room for 12 hours before testing. Avoid using perfumes, alcohol, or other interfering substances during testing.

Le Xin Electronic Technology offers two series of formaldehyde detectors—electrochemical and semiconductor—covering all scenarios from home use to professional testing.