By Shane HarrisonBBC Ireland CorrespondentImage source, Getty ImagesA controversial Irish government proposal to ban the commercial sale of turf is set to be discussed later on Tuesday.The Republic of Ireland's environment minister and Green Party leader Eamon Ryan says the measure is necessary. He said air pollution was responsible for about 1,300 deaths in the country every year.The proposal has met strong criticism from backbench TDs (MPs) in coalition partners Fianna Fáil and Fine Gael.But those in favour of the measure remind people of the health benefits of the ban on smoky coal in Dublin in the 1990s.