Moreover, the emissions of VOCs and NO components will indirectly influence the production of ozone in the atmosphere (Colborn et al.,2014). Photochemical modelling in 2012 showed an increase in 8-h ozone design values of up to 1.1. 10" ug/m in the Haynesville Shale region (Kembali Cook et al., 2010) while the LQs is 1.0. 10 ug/m (ACGIH, 2005). An ozone formation simulation has been performed with the Houston Advanced Research Centre (HARC) neighbourhood air quality model based on regular and non-routine emissions. Under average conditions, ozone concentrations could increase above 6.3. 103 ug/m" at km downwind from the shale gas development facility (Olaguer, 2012). These levels exceed the human LQs by a factor 60 (ACGIH,2005).