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Wed June 26, 2013
Tracking Air Quality in the Roaring Fork Valley
The US Supreme Court is in the news for decisions on same sex marriage and voting rights... but the highest court in the land is also planning to look at air pollution. At issue is who's to blame when air quality monitors go way past the legal limit. The court announced Monday it will soon review a 2011 EPA rule... one designed to help protect communities downwind of power plants. Part of the problem is figuring out how to regulate air pollution that goes across state lines. Aspen Public Radio’s science reporter wondered how air quality is measured and tracked. From a field in Carbondale, here’s Ellis Robinson.
There's a vast network of air quality monitoring sites across the country taking precise measurements of harmful pollutants 24/7. They're known to the scientists who use them as SLAMS, shorthand for State and Local Air Monitoring stations. Two environmental health specialists from Garfield County walked me out to the “SLAM” in Carbondale.
I wanted to learn about what they do, and tried my best not to be in the way.
The equipment that Robert Vercellino and Morgan Hill work with is best described as a big… gadget. On top of a small platform, a tripod supports two metal boxes buzzing with pumps and lasers inside. A metal cyclone is fitted to a tube where air gets sucked into the boxes. Above that, a high-tech weathervane spins in the breeze, measuring wind speed, temperature, and relative humidity.
“If we were to have a wildfire event and we were seeing haze in the air, that’s where we would want to check and see what our PM 2.5 levels are.”
PM 2.5 means particulate matter smaller than 2.5 microns. For a sense of how big, or small, a micron is, just take the width of one of the hairs on your head. Now, divide that by 70. The particles are so small they can’t be seen by the naked eye. Oh, and there are billions of them everywhere. If you’re sitting in your car as you listen to this, you’re sharing that space with, oh, about ten billion particles or so. Hill explained how the instrument measures these small particles:
“It comes in through this inlet here... passes through this cyclones...it pulls the PM 2.5 through and then there’s actually a laser that shoots up and reads the displacement of the light basically.”
The instrument gives residents of Carbondale a reading of PM 2.5 every hour. The data on these particles are beamed straight to the Garfield County website where you can see real-time graphs and compare the ambient concentration to the limits set by the EPA.
Here in the Roaring Fork Valley, small particulate matter comes from a variety of sources.
“Your smoke can come from a number of different sources, we see a lot of smoke from wildfires in the summer.”
And in the winter?
“People have wood-burning stoves. diesel is another source, so truck engines, generators can release those PM 2.5 particles as well.”
So, what’s the fuss? Why is the supreme court going to spend the next year thinking about particles in the atmosphere, and why are Morgan and Robert’s expensive gadgets sitting out in this field? One big reason is health.
“The smaller they are, the farther they can travel, and the deeper they can get into your lungs.”
If small enough, particles can even wind up in your bloodstream. Exposure to PM has been linked to asthma, irregular heartbeat, even mortality. And while concentrations in the roaring fork valley have been relatively low this year, even a little exposure can cause health effects.
“Middle of last week was interesting for us too because we were looking at our monitor and the concentrations were going up and we were trying to figure out where the fire was. It ended up being Arizona.”
That brings us back to the EPA’s Cross-State Rule. Colorado itself is not covered by the rule, which applies mostly to eastern states with pollution from coal-fired power generation. But the heart of the issue remains: when the concentration of PM 2.5 spikes in Carbondale, do you start looking for sources here in the valley... or do you point the finger over to Arizona?
Either way, it all starts out in the field with gadgets sucking up air.