You need to buy a particulate filter that is designed to handle the type of particulates you are going to be around. Fine dust from sanding and working can often slip through some respirator filtration systems.
The filters you want should be approved by NIOSH and/or by OSHA according to their requirements for the types of particulates you will be exposed to.
Your filters should be created from activated carbon, non-woven fabrics, and melt-blown cotton to provide the most protection.
The best filters will eliminate 99.97 percent of the particulates in the air. The amount of filtration the filter provides should be listed on the manufacturer’s description of the equipment.