are introduced and the some environmental groups in germany have been pushing for a diesel ban for yaz and that convinced that pollution from diesel vehicles is a killer and this a this then you have research to back that claim let's first take a listen to what they're saying. there are more than fifteen million diesel vehicles on germany's roads drivers find them reliable and economical and they're popular with businesses transporting freight and goods. but the future of that popularity is in doubt in the face of a possible diesel ban vehicle sales have slowed. the new regulations address concerns over high levels of nitrogen dioxide in diesel emissions. the gas is linked to cardiovascular and lung disease in a study by germany's federal environment agency researchers linked nitrogen dioxide in diesel exhaust to some eight thousand premature deaths from heart related disease. i don't think politicians are serious about the results of these studies because otherwise we'd have to really enforce these driving restrictions. regardless of any doubt surrounding the findings one thing is cer

individuals who seem to turn to these mass killing machines and mowing down people in schools in, calf tier "yaz," in churches, at rock concerts or country music concerts really has taken on a life of itself. >> thank you so much. tom costello for nbc news. joining us right now is senator bill nelson of florida. senator, pren says in these situations don't talk politics. talk about prayer and talk about thoughts. this is the only instance in which we do talk about guns. what is your reaction to the use of guns by this shooter? all these people dead. he had an ar-15, multiple magazines. what do you make of that situation? >> i want to answer that specifically but let me give you some new information. he wore a gas mask and smoke grenades. he set off the fire alarm so the kids would come out into the hallways. and thus, he had the opportunity with a crowded hallway to start picking off people. and again, it illustrates the horror as tom just outlined. you know, pulse nightclub was just a couple of years ago, 49. 59 in las vegas. when is this going to stop? so your question is the politics. it's no