As awareness of indoor and outdoor air quality grows, CO2 sensors are becoming widespread. However, many people do not understand the differences between indoor and outdoor CO2 sensors, leading to misconceptions during purchase. This article explains these differences to help readers make better choices.

I. Working Principle

The working principles of indoor and outdoor CO2 sensors are essentially the same, primarily using:

● Infrared Absorption (NDIR): Measuring based on the principle that CO2 gas absorbs infrared light at specific wavelengths.

● Electrochemical: Measuring current signals generated by the chemical reaction between CO2 gas and an electrolyte.

II. Measurement Range

There are significant differences in their measurement ranges:

● Indoor CO2 Sensors: Primarily used for air quality monitoring, with a range typically between 0-2000ppm.

● Outdoor CO2 Sensors: Used for environmental monitoring, with a broader range typically from 400-5000ppm.

III. Accuracy

Accuracy requirements also vary:

● Indoor CO2 Sensors: Since indoor fluctuations are smaller, higher accuracy is required, usually within ±50ppm.

● Outdoor CO2 Sensors: Due to larger environmental variations, accuracy requirements are relatively lower, generally within ±100ppm.

IV. Application Scenarios

● Indoor Sensors: Applied in homes, schools, offices, and hospitals to monitor air quality and prompt ventilation.

● Outdoor Sensors: Applied in environmental monitoring, agriculture, and traffic for research and pollution control.

V. Purchase Suggestions

Select the sensor based on your specific scenario. For indoor use, choose a 0-2000ppm range with ±50ppm accuracy. For outdoor use, opt for 400-5000ppm with ±100ppm accuracy. Always read the manual and consult professionals when choosing specific technical parameters.