Watching Disease Happen: the Pathology of Air Pollution

May 2, 2013

For Air Quality Awareness Week, Jennifer Pemberton has been asking local experts to help explain Cache Valley’s air pollution problem to residents. In today’s report, she tours a lab on the campus of Utah State University, where the effects of particulate pollution on human health are easy to see -- with the right equipment.

It’s not ethical to experiment with living humans subjects -- putting them in a room and pumping it full of diesel exhaust for 12 hours a day, for instance. But it is important to be able to study the effects of inhaling liters and liters of polluted air when you’re on a run along the Logan River, for instance, during a winter inversion.

Luckily residents of Cache Valley are their own control group. Most days we have some of the cleanest air in the country and then in the winter, some of the worst. Comparing our pulmonary function before and after an air pollution event is the next best thing to making someone run behind a diesel truck.

Dr. Randy Martin, who studies particle air pollution for Utah State University calls Cache Valley “A giant experimental basin for PM2.5”. One of his research partners, USU Toxicology Professor Roger Coulombe agrees:

“That’s what I like about Utah State. We can do research here that’s really relevant and some of the worst air pollution ever measured is right here in Cache Valley...It provides us a great laboratory to study air pollution here.”

Dr. Coulombe has completed 2 clinical studies with living Cache Valley residents.

“We took baseline measurements when the air was clean, measurements related to pulmonary function, biomarkers in plasma, and other indicators of health during an air pollution event -- which we defined as over the ambient standard of 35 micrograms.”

That’s 35 micrograms per square meter of air. That’s the EPA threshold for a red air day.

“Then again we took baseline measurements afterwards, after the air had cleaned up in the valley to see if there were long term effects....What they found was that there was a rather immediate reduction in pulmonary function in Cache Valley residents. We found also some blood markers of disease that are associated with impending or chronic cardiovascular- cardiopulmonary disease...We knew what to look for in the plasma of cache valley residents because of several years of studying the effect of pollution in a petri dish in human cells.”

Dr. Coulombe’s group is still studying human lung cells in petri dishes. I visited his lab in the shiny new Agricultural Sciences building on the USU main campus in Logan, where he has a student from Japan, Tsubasa Ikeya, preparing some petri dishes to compare the effect in human lung cells of local Cache Valley PM2.5 particles and diesel exhaust particles.

In the shiny new Agricultural Sciences building on the campus of Utah State University, toxicology professor Roger Coulombe studies the interaction between PM2.5 and human lung cells.

“We keep all of our cells growing in here. Those are actually human lung cells in there. When we grow the cells up we put them in smaller plates and put the PM’s right on top of them for varying amounts of time.”

From the body temperature incubator, we move on to the deep freeze. Dr. Coloumbe puts on gloves and opens a styrofoam cooler that says PM2.5 in sharpee on the lid. There are plastic and metal disks that we just have to believe are covered in particle pollution. They don’t even use a microscope on these; they just weigh them with a super sensitive scale and know how much pollution is on each disk. Some time next week Tsubasa Ikeya will drop the particles on his lung cells, wait 24 hours, then look for changes.

“Some of the early indicators of cardiovascular disease and cancer....Like particles from Beijing, Mexico City, and dozens of other locations, Cache Valley PM2.5 triggers an inflammatory response in the lungs of people. It causes an increase in what is called C-reactive protein, which is a well-known, validated biomarker for impending cardiovascular and cardiopulmonary disease. It actually happens very rapidly. Like PM2.5 around the world, disease begins very quickly upon exposure.”

Dr. Coulombe has a great view of Cache Valley from his office. The PM2.5 concentration is less than 10 micrograms per cubic meter today, which is under the federal standard of 35 but still not safe. And after learning about the damage that one particle can do to one lung cell, it’s hard to look out at the blue sky and the snow-capped peaks and trust your own eyes.

What Drs. Randy Martin and Roger Coulombe are researching up here on the hill isn’t happening in a bubble.

“I think there’s tremendous application to the research we do here with my colleagues in that we know that the dose response curve for adverse effects is very steep. What that means, practically, is that if we can reduce our PM2.5 here in Cache Valley just by a small amount, the benefits to public health are tremendous...Sometimes I feel like the reluctant mayor of that city in the movie Jaws trying to put a good face on these shark attacks happening and get people to come to his community.  We’ve got to figure out ways and do it ourselves, show the country and the world that we Utahns are smart and that we can solve our own problems and not wait for others to tell us what to do. Improving our health is a family value and I think it’s something we can all agree upon.”