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OnAir@AAAR: Urban V. Rural—How Do Coarse Particles Compare?

2010 March 25

I sat down with Mike Hannigan, EPA grantee and UC Boulder scientist, Tuesday to talk about his innovative research on coarse particles.

mike hannigan

“Coarse particles are basically what we think of as dust,” Hannigan explained.

“But what’s tricky is that depending on where you are, the dust can look very, very different.”

In an urban environment, for example, a large percentage of coarse particle pollution comes from the brake-wear of stopping and slowing vehicles. In rural areas though, agricultural dust and windblown soil play a big role.

“The major question we’re trying to answer is—do these different kinds of coarse particles cause different health effects? And if so, should this impact the way coarse particles are managed in the future?”

A handful of studies have suggested increased hospitalizations for cardiovascular and respiratory illness with exposure to coarse particles, but a comparison of urban and rural effects has never been done before.

Hannigan and colleagues set up monitors in Denver, Colorado and in a rural town called Greeley, about 100 miles to northeast of Denver. The monitors measure both coarse and fine particles continuously, producing hourly averages that give a clear picture of how particle exposures vary over time.

Hannigan’s group has been monitoring for just over a year and will continue for another two. After monitoring is complete, the data will be turned over to epidemiologists to look for any associations between coarse particles and hospitalizations, deaths, and birth outcomes in Denver and Greeley.

“ Nobody has ever looked at birth outcomes as a possible effect of coarse particle exposure before,” Hannigan said, “so this is very new.”

Over the three years of monitoring, Hannigan and colleagues will also collect samples for lab analysis in an effort to determine the origins of coarse particles in each area.

“You can measure barium in samples, for example,” Hannigan explained, “and since brakes are really the only place you find barium… that tells us something about the source of those particles.”
In the future, Hannigan hopes to expand his analysis to include biological sources of coarse particles like pollen and bacteria.

“We can sequence the DNA of particles off the filters from the field and understand more about where they are coming from,” he said.

“It’s all very exciting; it’s going to add a lot of knowledge to the scientific community.”

About the Author: Becky Fried is a science writer with EPA’s National Center for Environmental Research. Her OnAir posts are a regular “Science Wednesday” feature.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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3 Responses leave one →
  1. Tim Stevens permalink
    March 25, 2010

    My sense is that this is especially important research. I never knew that so much of the particles we breath in (in an urban setting) are from braking vehicles.

  2. Michael E. Bailey permalink
    March 26, 2010

    This news sounds like it will have major impact. Most urban coarse PM is made up of barium from car brakes. The CalEPA’s Air Resourses Board talked about a study several months ago that said pregnant women who live close to major freeways have a greater rate of miscarriages and ohther pregnancy problems than those who live fiurther away. And I have a number of friends with asthma and ohther breathing problems where the breathing gets a lot worse for them the more dust in the air. This is pioneering research. Best wishes, Michael E. Bailey.

  3. edgardo berraz permalink
    March 27, 2010

    It’s a very interesting investugation,already I never heard about the procedence of coarse particles,even more,I never think about this,more than feel very unhappy when storms of dust invade the city.It seem to me very important identifing this particles,as the case of barium,yet it’s a very nocive element,who breathing could be cause of silents nocive inclusion in lung’s defensive sistem,that could be responsible for future illness,and maybe also having relationship with lung’s cancer.

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