Methods to predict variations of lower explosion limit associated with hybrid mixtures of flammable gas and dust

•A dimensionless parameter called sensitivity index was defined, which can be used to quantitatively express the explosion sensitivity of hybrid mixtures.•A calculation method for the sensitivity index was established using maximum explosion pressure as well as explosion indices of the flammable gas and dust.•A predictive approach for determining variations of the lower explosive limit of hybrid mixtures with sensitivity index was established.•The predictive performance of the newly predictive approach was verified using data from other hybrid mixtures.