I have pulmonary problems so I have a box full of masks that work and don't. The mask I wear for street dust is the Fightech. It has a large face and allows for more air in front of my mouth and nose. I sewed up my own filters out of thick ShamWow material by using the disposable filters as a template. I remove the filter and wash out all the snot and dirt that gets deposited during my rides. The ShamWow dries fast and can even be used wet.
Amazon 20 USD