▎ 摘　　要

The advancements in present world like industrial revolution, transport system, agriculture, food industry, pharmaceutical industry and electricity generation have made our life easy and comfortable in many aspects but they also have deleterious effects on our life. The pollution from industries, household waste, combustion of fossils etc. has introduced many harmful chemicals in air and water which have badly affected the life on our planet. The presence of undesirable gases in air has serious adverse effects on health and quality of life. Therefore, monitoring of these substances becomes important. Graphene based chemiresistor sensor are proved to be promising materials for the detection of toxic air pollutants. This article summarizes the recent progress of Density functional theory (DFT) based studies in the field of graphene based gas sensors. This article discusses the working mechanism of graphene based chemiresistor and also provides the information that how the sensing ability can be enhanced. The information given in the article will help the young researchers in the selection of suitable dopant and nano-clusters for graphene based surfaces to make them more selective and sensitive towards the analytes.