“…[20][21][22] In some parts of the world, despite lower levels of traffic-related air pollution in rural areas, the prevalence of respiratory symptoms and COPD is considered to be high in farmers, 21,23 especially in grain, swine and dairy workers. 23 The increased frequency does not seem to be related to episodes of farmer's lung disease or sensitization to thermophilic actinomycetes. 23 Grain, rice, crop, vegetable and dairy farming on small family farms in close proximity to living areas is a common practice in Isfahan villages and this may result in the increased frequency of respiratory illnesses observed, despite there being an absence of traffic-related air pollution.…”