Possible Mechanisms for Disease

We now have multiple hypotheses to explain how the chemical and physical properties of PM could produce disease. Further, we can now experimentally investigate the mechanisms that enable very small concentrations of inhaled PM to cause changes in the heart and lung that lead to increased illness and death. The laboratory and field evidence does not implicate one specific toxic quality of PM to the exclusion of others. Qualities such as the size of the PM and presence of certain chemical components, such as metals, all appear to contribute to its toxicity.