Problem
Diesel engines emit a complex mixture of air pollutants, including both gaseous and solid material. The solid material in diesel exhaust is known as diesel particulate matter (DPM). More than 90% of DPM is less than 1 µm in diameter. Particulate matter are associated with adverse health effects including cardiovascular and respiratory hospitalizations, and premature death. Human health risk assessment is the process of analyzing information to determine whether an environmental hazard might cause harm to exposed persons. Using the process of risk assessment, explain the four steps of the process to determine the risk of cardiovascular disease resulting from exposure to DPM.