Although the day of Yom Kippur is a day of a day of affliction, and we therefore withhold from ourselves many physical pleasures, like eating, drinking, bathing, and the like, fragrances are not included in this category: smelling good smells and making a Beracha (blessing) on them. And therefore, not only is it permissible for a person to have fragrances that they can smell, it is even encouraged for them to do so in order to be able to be mashlim me'ah Berachot (complete one hundred blessings). A person could take a myrtle branch and make Atzei Besamim (fragrant trees); they could take na'na mint and make Isvei Besamim (fragrant herbs); they could take other artificial things and other types of fragrances and make Minei Besamim (various spices); and they could even take a fruit and make the Beracha HaNoten Reiach Tov BaPeirot (Who gives fruits a good fragrance).
A person could do this frequently, periodically throughout the day of Yom Kippur, adding for themselves somewhere in the vicinity of 15 to 20 extra Berachot in order to reach 100 Berachot. One does not have to be concerned, when taking a fruit, that he may accidentally eat it. A person can scratch an orange or an apple a little bit, sniff it, make the Berachot, and thereby be able to mashlim me'ah Berachot.