MQ-131 Ozone Gas Sensor

Specifications

• Target Gas: Ozone (O3)
• Detection Range: 10ppb - 2ppm (Parts Per Billion / Million)
• Heating Voltage: 5V DC ±0.1V
• Loop Voltage: 5V DC ±0.1V
• Load Resistance: Adjustable (Onboard Potentiometer)
• DO (Digital Output): TTL Logic (0/1). Low signal when ozone concentration exceeds the set threshold.
• AO (Analog Output): 0-5V Analog voltage (Higher concentration = Higher voltage).
• Sensitivity: High sensitivity to Ozone; low sensitivity to CL2, NO2, etc.
• Response Time: < 10s (Pre-heat required)
• Dimensions: 32mm x 22mm x 27mm

Applications

• Environmental Monitoring: City air quality stations and portable pollution trackers.
• Industrial Safety: Ozone generator leakage detection.
• Smart Home: Air purifier filter monitoring and control.
  Weather Stations: Advanced weather monitoring kits.

 Wiring Guide: Connecting to Arduino UNO:

• VCC -> 5V (Stable power source recommended)
•  GND -> GND
• D0 (Digital) -> Digital Pin 2 (For simple threshold switching)
• A0 (Analog) -> Analog Pin A0 (For concentration reading)

Note: Like all MQ-series sensors, the MQ-131 requires a Pre-Heat time of 24-48 hours (power on) for the most stable and accurate readings during its first use. For quick testing, a 2-minute warm-up
is sufficient to see signal changes.

Technical Table:

Package Includes: 1 x MQ-131 Ozone Gas Sensor

Frequently Asked Questions (FAQ)

•  What gas does the MQ-131 detect?
  It specifically detects Ozone (O3).
• What is the detection range?
  It detects concentrations from 10ppb to 2ppm.
• Does it work with 3.3V devices like ESP32?
  The analog output is 0-5V. You need a voltage divider to step it down to 3.3V for ESP32 analog pins.
• Does it require calibration?
  Yes, for precise PPM readings, calibration against a known concentration is recommended.
• Why is the sensor getting hot?
  It is normal for the sensor to get warm (internal heater) during operation.
• Can I use it to detect Oxygen?
  No, it is specific to Ozone.
• How do I adjust the sensitivity?
  Use the blue potentiometer on the back of the module.
• What is the warm-up time?
  For best accuracy, 24+ hours burn-in is recommended for new sensors.
• Is it waterproof?
  No, the mesh is not waterproof.
• Can it detect Ozone leaks?
  Yes, it is suitable for detecting leaks from ozone generators.
• What is the lifespan of the sensor?
  Typically 2-4 years depending on the environment.
• Does it measure CL2?
  It has some cross-sensitivity to Chlorine but is optimized for Ozone.
• Is code available?
  Yes, standard MQ-sensor libraries for Arduino work with this module.
• What is the current consumption?
  Approximately 150mA due to the heater.
• Can I use a battery?
  Yes, but due to heater consumption, it will drain batteries quickly.
• Is the sensor pre-calibrated?
  No, factory standard baseline only.
• What is the output voltage in clean air?
  It varies, usually low, but depends on calibration.
• Can I replace the sensor element?
  The sensor is soldered to the PCB; replacing the whole module is easier.
• Does humidity affect readings?
  Yes, extreme humidity can affect resistance values.
• Is this the high or low concentration version?
  This is the low concentration (10ppb-2ppm) version suitable for air quality.