When working outdoors, you can greatly reduce your exposure to the sulfur compounds in vog by using a vinyl or rubber gas mask that’s fitted with cartridges rated for acid gases and particulates: many welding supply shops, and even some hardware stores, stock these items. For optimum performance, make sure that you purchase a mask that is properly fitted to your face and gives a good seal around your nose and mouth. The best way to do this is to find an experienced professional who works at the store to assist you with the fit and can give you tips on how to get the most benefit from the mask. It’s also important to purchase the correct cartridges for these masks: you will need cartridges that remove both dust and acid gases; cartridges that will remove these compounds as well as organic vapors are also readily available. Another important consideration with this type of mask is that their ability to remove gases and aerosols is greatly reduced by the presence of beards and mustaches due to the poor seal between the mask and your skin. (In critical work environments, where properly fitted masks are required, beards and mustaches are prohibited.)
Conventional dust masks that are found in most hardware stores are not nearly as effective as the more sophisticated masks intended for acid gas removal. In times past, when mask technology was less sophisticated, and when gas masks were much less common, the inexpensive dust masks were soaked in a baking soda paste and then allowed to dry before use as a gas mask. Although some relief was obtained using this strategy, they are a poor second to a properly-fitted gas mask.