This study presents a brief overview of the main features, theoretical formulations and validation tests of some Lagrangian micromixing models, currently used for estimations of the ensemble mean and the turbulent fluctuations of concentration. Their application fields regards several pollutant dispersion phenomena such as: accidents (power or production plants, terroristic attacks, hydrocarbons storage and transport, extraordinary emissions), odours (power plants and energy production from waste resources-compost, dumps, incinerators, biogas storage and smokes-, high enthalpy geothermic plants -sulfide hydrogen-, animal farms), micro-scale dispersion from continuous or spot emissions (traffic pollutants, power and production plants, dispersion in aquatic environments…), industrial processes (combustion, pollutant treatment,…), strong non-linear relationship between concentration and damage (inflammable substances, explosions,..), reactions depending on instantaneous concentrations.