A respirator 10 that includes a harness 14 and a mask body 12 that is air permeable. The mask body 12 has a sinus region 40 and a primary filtering region 44 and comprises at least one nonwoven fibrous webs, which web includes a layer of filter media. The sinus region 40 of the mask body 12 exhibits a resistance to airflow that is greater than the primary filtering region 44. This resistance to airflow is achieved through an alteration of the intrinsic structure of the plurality of nonwoven fibrous layers in the sinus region 40 without adding additional material to the mask body. The alteration of the intrinsic structure assists in preventing eyewear fogging.