EVs are powered by an electric battery so, unlike petrol or diesel vehicles, they don't produce any tailpipe emissions or air quality pollutants.
Because they run on electricity, EVs can increase energy use. However, in Australia, an excess of electricity is generated at night when there is reduced demand. This capacity can be used to charge EVs, but will increase energy production. If this extra electricity production comes from renewable energy generators like wind turbines, the extra consumption from EVs will not cause more emissions. If it comes from fossil-fuelled generators, then emissions will increase accordingly.