Is there any consensus in the cause of chronic sinusitis being related to molds as a 1990's study showed ? i have a postnasal drip 24/7.

Not really: Chronic sinusitis can be secondary to several ailments, from a variety of nasal allergies, and not only mold, to immunodeficiency or polyps or anatomical abnormalities in the sinuses. You need to be tested for environmental allergies and treated appropriately.

Allergies: So there is a good consensus at this time that chronic sinusitis is caused by inflammation of the lining of the nose and sinuses that often leads to sinus infections with bacterial build-up. This inflammation can be caused be anything that inflames the nasal and sinus mucosa, like allergies to mold, dust, animal dander etc., smoking, toxic fumes, viral illnesses, inhaled drugs, and others.