Whether or not a respirator is helpful to have in your arsenal of tools is contingent upon what you expect to use it for- mixing pigments, while painting, et cetera.
To further elaborate, respirators require filters that protect you from certain fumes and particulates and vary with each type/model of filter cartridge. They are a proven preventive measures with many products; however, encaustic's obscure exsitance makes it difficult to find accurate data. This conflicting data about respirators and there effectiveness against wax fumes or rather encaustic fumes are frustrating to say the least; I am not going to add to the confusion by adding my own unfounded data.
Rather, I will focus on other preventative measures that could help you reduce risk; which I mean read Encaustic Safety Precautions and ventilate your studio space and/or ask a trusted expert on chemicals and respirators. As for particulates there is fairly well known data- just remember to read the packaging and purchase the one most effective for the job.
For more information go to NIOSH-Approved Particulate Filtering Facepiece Respirators on the CDC website.
