This review discusses the mechanisms, parameters, and applications of metal oxide chemoresistive gas sensors, focusing on spinel ferrites. The paper highlights the importance of monitoring air quality due to the harmful effects of gases like NOx, CO, and CH4 on human health and the environment. Traditional monitoring methods are expensive, so nanotechnology has been used to develop cost-effective, sensitive, and selective gas sensors. Spinels, with their tunable properties, are promising for gas sensing due to their stability and electrocatalytic behavior. The paper reviews various gas sensing mechanisms, including electrochemical, optical, acoustic, catalytic, magnetic, and semiconductor sensors. It also discusses the synthesis techniques for nano-ferrites, such as co-precipitation, sol-gel, hydrothermal, and combustion methods. The key parameters for gas sensors include phase formation, crystallite size, surface area, selectivity, and response/recovery time. The review also examines the influence of gas concentration, temperature, and humidity on sensor performance. Different types of metal oxide sensors, such as n-type and p-type, are discussed, along with their applications in detecting gases like CO2, LPG, and NO2. The paper emphasizes the need for sensors that can operate at low temperatures with fast response times and high sensitivity. It concludes by highlighting the importance of developing new materials and techniques to improve the performance of gas sensors for environmental monitoring and safety.This review discusses the mechanisms, parameters, and applications of metal oxide chemoresistive gas sensors, focusing on spinel ferrites. The paper highlights the importance of monitoring air quality due to the harmful effects of gases like NOx, CO, and CH4 on human health and the environment. Traditional monitoring methods are expensive, so nanotechnology has been used to develop cost-effective, sensitive, and selective gas sensors. Spinels, with their tunable properties, are promising for gas sensing due to their stability and electrocatalytic behavior. The paper reviews various gas sensing mechanisms, including electrochemical, optical, acoustic, catalytic, magnetic, and semiconductor sensors. It also discusses the synthesis techniques for nano-ferrites, such as co-precipitation, sol-gel, hydrothermal, and combustion methods. The key parameters for gas sensors include phase formation, crystallite size, surface area, selectivity, and response/recovery time. The review also examines the influence of gas concentration, temperature, and humidity on sensor performance. Different types of metal oxide sensors, such as n-type and p-type, are discussed, along with their applications in detecting gases like CO2, LPG, and NO2. The paper emphasizes the need for sensors that can operate at low temperatures with fast response times and high sensitivity. It concludes by highlighting the importance of developing new materials and techniques to improve the performance of gas sensors for environmental monitoring and safety.