don milton, a leading expert on airborne infection transmission with the university of maryland and mppen paceman, who invented a device to help masks fit better. if you have questions please asking them on our facebook live stream and we'll try to get you answers. welcome, both of you. >> thank you very much. >> hi, good evening. >> dr. milton, i'm starting with you. the raging debate right now is with evidence suggesting the variants spread faster and easier, european countries are moving to make n 95 masks a requirement. do you think we need to level up in terms of the masks that we wear in the u.s.? >> well, yes, it would be good to get better masks. of course, we still have people who don't want to wear masks or wear them under their nose. so wearing the mask you have well first is the number one. and then let's get to better masks. >> all right. so let's talk about that. what are better masks? i know there is a difference between filtration and fit. spo let's talk about both aspects and why both are so important. >> well, filtration is does a patricle get through the filter. and