And perhaps you're wondering where you can get your own free mask from the CDC or the National Institute for Occupational Safety and Health ( NIOSH ) . External Nose Clip N95 with nosepiece today, we're saying resoundingly yes-you need to keep your mask on. Large extra large N95 face mask they also come in a few different types, so it's important to choose one that fits your needs-and is approved for use where you'll be wearing it. And that workers use a new mask for each shift they work. For industries where workers are exposed to irritants such as ACIds, half-mask respirators are the ideal choice. NIOSH-approved masks always come with an approval label on or inside the mask packaging, either on the box or in the users' instructions.