These aprons protect workers from hazardous dry particulates and non-hazardous liquid splash and spray. Dry particulates are larger in size than aerosols and include dust and dirt. Splash is non-pressurized or lightly pressurized when it contacts a garment, while spray is pressurized. Aprons cover the front of the worker from the chest to the knee or below. Sometimes called bib aprons, they are sleeveless and have an open back, so workers who wear them all day stay cooler than wearing garments that cover the front and back.