Development and Validation of an Ammonia (NH3) Gas Concentration Measurement Device for Industrial and Health Application

Ammonia (NH₃) is a harmful air pollutant that not only contributes to environmental damage but also poses serious health risks, particularly in confined or poorly ventilated spaces like farms, waste management facilities, and industrial settings. Monitoring ammonia levels accurately is essential for protecting both the environment and public health. This study focuses on creating a cost-effective, real-time monitoring system designed to detect ammonia in the air. The system integrates the MQ135 gas sensor and the DHT11 temperature and humidity sensor with an Arduino Mega 2560 microcontroller. By tracking ammonia levels along with temperature and humidity, the device offers a more complete view of air quality conditions. Before physical testing, the system was validated through circuit simulation to ensure proper communication between components, identify any circuit issues, and assess the performance of the signal processing algorithm. Calibration was a key part of development, aimed at improving accuracy across various ammonia concentration levels while considering environmental fluctuations. Lab tests showed that the MQ135 sensor produced consistent results with low noise, achieving an average error margin of just 2.11%. The most accurate readings were observed within the 20–45 ppm range. Incorporating temperature and humidity data from the DHT11 sensor opens the door to future enhancements, such as environmental compensation algorithms. Overall, the system proved effective for general air quality monitoring, with potential for future upgrades like automatic calibration and support for detecting multiple gases