Every day, each of us breathes in dangerous toxins like carbon monoxide, ground-level ozone, lead, nitrogen dioxide, particulate matter and sulfur dioxide. That troubles Matthew Campen, who’s been studying such common pollutants as engine exhaust and wood, coal and tobacco smoke since 1991.
Campen knows these toxins cause serious damage to the human body beyond the lungs. “Air pollution is associated not just with respiratory diseases, but also cardiovascular disease,” he says. “Epidemiological studies have long shown that there are increased cardiovascular deaths on bad air pollution days. But it’s unclear why something you breathe in – that doesn’t really physically get past the lungs – causes vascular disease.”
So Campen and his team are digging deeper. “From a public health standpoint, it’s important that we learn more about how the everyday pollutants we’re all exposed to affect us and remain aware that highway-related emissions are still a significant health problem,” he says.
Campen suspects that when we inhale air pollutants, potent particulates and gases somehow alter our blood chemistry, causing vascular inflammation. His team is investigating the biological pathways these toxins exploit to access the vascular system, and ultimately how they lead to cardiovascular insult. “We’re taking what we’re learning from air pollution and lung disease and linking it back to coronary artery disease,” he explains.
“I’m a discovery person – I look for the ‘eureka’ moment,” Campen says. “I live for designing studies where we have a hypothesis, we do an experiment and we prove it. Our biggest challenge is to ensure that what we see at the molecular level actually is something that translates to humans.”
Studies have shown that when an air pollutant bypasses the lungs to reach a blood vessel, it’s not as damaging as when it is inhaled, Campen says. “We’ve also discovered a blood-borne signal originating in the lung - but found outside of the lung – that causes inflammation in blood vessels and the brain. So there’s something essential to various pollutants entering the lungs first.”
Campen believes that damaged proteins or fragments of proteins he calls “molecular shrapnel” are formed following exposure to toxic pollutants. When they breach the lungs and enter the blood stream, the cells lining the blood vessels become irritated. “They think the molecular shrapnel is a sign of damage,” he says, “so they respond appropriately with inflammation, which can contribute to long-term heart disease.”
No single chemical in air pollution appears to be responsible, Campen says. “When gaseous and particulate portions of exhaust combine, gases adhere to particles, which seems to make it more toxic to the cardiovascular system,” he says. “We need to know which pollutants are most potent, how they affect other parts of the body, and which people are most susceptible.”
The good news, Campen says, is that the health risks from air pollution can be reduced. “Try not to locate or exercise in industrial areas or near transportation corridors,” he suggests. Genetics and nutrition also play a role. “We think that polyunsaturated fats already present in the lungs help protect the lungs and body from generating these ‘molecular shrapnel’ – these fragments of proteins,” he says. “So a diet of polyunsaturated fats is good for our lungs. Vitamin C also is a great defense for your lungs.”