Particulate Matter and Causes of Cardiopulmonary Toxicity from Diesel
What is Cardiopulmonary Toxicity?
Cardiopulmonary refers to the lungs, heart, blood, and the smaller structures associated with them. Toxicity refers to a toxic condition. So, cardiopulmonary toxicity refers to the adverse effects on the blood systems, heart, or lungs resulting from being exposed to toxic chemicals. Some adverse effects include cardiac ischemia, pulmonary inflammation, and an increased level of toxins in the blood.
Cardiovascular and respiratory issues have been associated with people being exposed to traffic-derived particulate matter. The amount of exposure and amount of traffic-derived particulate matter a person is exposed to will determine how they are effected. The person’s overall health also plays a role.
Size Ranges and Measurements
There are different size ranges associated with cardiopulmonary toxicity. Ultrafine is <0.1 micro, fine is 0.1 to 2.5 micro, and coarse is 2.5 to 10 micro.
Objectives and Rationale
Studies have been conducted by the Environmental Protection Agency using mice to test acute cardiopulmonary toxicity. They tested how size-fractional particulate matter played a role and used samples from different distances on a highway.
Many scientists will spend at least two weeks collecting the different sizes of traffic-derived particulate matter. Samples are most often extracted in methanol, then dried, and diluted with saline. Scientists then analyzed the chemical for constituents. They will then present this to mice through oropharyngeal aspiration. They will assess them for signs of cardiopulmonary toxicity associated with roadside particulate matter derived from traffic. They will often assess them multiple times at with each assessment being at least six to twelve hours apart.
The overall chemical composition between particulate matter was similar, but the near road samples had higher amounts of endotoxin particulate matter, as well as certain metals than the far road samples did. Each size had differences in the major chemical class ratios. Both near road and far road coarse particulate matter produced significant pulmonary inflammation regardless of the distance, while both near road and far road ultrafine particulate matter lead to cardiac ischemia – reperfusion injury.
In conclusion, both ultrafine and coarse particulate matter affected the heart and lung, respectively. There were no significant differences in the chemical makeup and overall toxicity end points between near road and far road particulate matter. The results suggest that the different sizes of particulate matter might result in different toxicologic mechanisms in pulmonary and cardiac tissues.