What are the inciting agents causing HP?

Disease caused by inhaling organic dust/ inorganic chemicals in a sensitized individual. Major factor is the size (>10mcm stopped in nose, 5-10mcm cleared by cilia/ extrinsic asthma, 0.3-5 mcm reach alveoli cleared by macrophages or cause HP) It was though to be an occupational hazard/ recreational/ environmental. Associated diseases: Bagassosis (moldy sugar cane), Farmer's lung (inhaled actinomycetes [micropolyspora faeni - in hay/soil/ grain/ AC/ humidifiers/ pools/ furnaces]) Inhalation of animal products [serum protein, urine protein, feathers - bird fancier's lung/ gebril keeper lung/ turkey handler lung] hapten protein chemicals Drugs [HP-like illness- amiodarone, gold, minocyclin, cocaine]