IDUINO MQ-135 SnO2 Benzene Sulfide Air Quality Sensor module details

Features: good sensitivity of harmful gases with wide range of concentration, long life, low cost, simple driving circuit. High sensibility over ammonia gas, sulfide, benzene series vapor, also ideal for smoke and other harmful substance detection. This sensor can detect various harmful gases. 

MQ-135 is a low-cost sensor suitable for many applications.