My impression of the restaurants in Juan Dolio is that most have their cooking stoves and ovens "enclosed" and away from the boulevard, such that the debris and the dust being lifted by the construction taking place is far removed from the foods being prepared and served.
However, there are a few I have also seen that have the cooking facility right up against the street, with their ovens, food preparation and storage directly exposed to the dangerous particles that are being swept toward their ovens. Pizza ovens that are at high temperature are not in question- its more the perparation process and food exposure that is worrisome. I don't think that these would pass any sanitary inspection from the authorities and in fact might be in violation of codes directly dealing with food service enterprises.
If you frequent any one of these, you are running a health risk and should reconsider and/or suggest to the owners that they seek more sanitary alternatives if they pretend to provide this business to the general public. Its in the interest of public health and safety that this should be addressed. I can't see how these would be in command of a permit and/or registration to do business this way. If you are frequenting any of these places ask to see their health and sanitation certificates before eating there... it will do us all good to make sure these places are up to code.