Disease statesRegardless of how one defines climate change there is increasing awareness that this condition is caused by pollution, and generalized disease states on a global scale and on a more individualized level, respiratory disease can occur. These effects may not be recognized immediately but over time and with increased opportunities for exposure, pollutants regardless of their source, which include a range from carbon monoxide released into the atmosphere to nitrogen gas buildup in silos found on farms, can and do progress to immunologic disorders or infection. The portal of entry and target organ is often the lung. While mortality due to infectious disease has decreased, respiratory related infections still remain a major problem. In agricultural areas, nitrogen dioxide buildup can impair an individual's immune response and working with farm products which may occur during hay making season can lead to infections.