Why would lung disease be more common in a large urban area thats in a remote rural area?

Rural areas are characterized by low population density, isolation of and long distances between individuals and communities, and long distances from urban centers. Rural communities face difficulties protecting their supply of health care providers; such difficulties include recruitment and retention of physicians and maintenance of the viability of rural hospitals.1,2 Elderly people in rural areas also travel longer and wait longer for outpatient care and use fewer preventive services than do their urban counterparts.3,4 In a recent study by Pathman et al.,5 older adults who lived in rural areas with low physician density were significantly more likely to travel 30 or more minutes to a provider. These factors predict negative effects on the health of the rural population, which suggests that urban and rural differences in health outcomes may exist because of differential access to services.