YODER – On Wednesday, April 23, the Department of Environmental Quality (EPA) held an open house on particulate matter (PM) monitoring and the next steps which can be taken to improve and continue to test the air quality in Yoder. The meeting was held at the Yoder Community Center for the purpose of the EPA’s findings. Air quality monitors have been installed in the Yoder area to collect dust particles in order to determine whether or not the air quality in the town has been affected by Dietzler Construction Corporation, which operates north of town. 

The meeting was structured to include a reminder on what PM actually is. 

“The agenda we’re doing is, we’re just going to kind of go back over and make sure everyone understands what PM is. The monitoring station objectives, why we’re here, what we’re monitoring for and why. Then we’ve got to summarize some of the PM10 data that we collected of years and months. There was 2.5 and then address some of the PM4 data that we collected. PM4, we were originally going to do for like three months, but we ran into some issues of getting equipment and equipment for us, so it took us a little to figure out. We ended up sampling through the end of March. We think we got a pretty good set of data for that,” Mark Gagen, Air Pollution Monitoring Program Manager from Wyoming DEQ said. “Then we’re going to go into talking about what are we going to do down the road, how can we continue with this process and have it developed.” 

Next, DEQ went around the room and introduced the staff members.

“What we have here, this might be familiar if you were here back in October. This is kind of a slide explaining what is PM and its fine particles emitted from a source, whether it’s a stack or a natural element like fire or windblown dust,” Dr. Leif Paulson, Air Pollution Monitoring Program Supervisor with the Wyoming DEQ said. “We kind of like to use this figure that the EPA (Environmental Protection Agency) has of a human piece of our hair and these blue spheres represent PM10. Ten meaning it’s a diameter less than or equal to 10 micrometers. Very fine. Then, even smaller than the blue spheres are the red ones. PM2.5, which are 2.5 or smaller micrometers. You might think of that as windblown dust. PM2.5 might come from smoke from a wildfire. Then ultra fine, which is not shown in this slide. Ultra fine particulates would be less than one micrometer. So, very, very, tiny.”

Paulson continued to explain the sizes of PM seen in the Yoder area.

“We installed, back in September of 2022, a Met One BAM (Eta Attenuation Mass Monitor) 1020 monitor that continuously monitors for PM10. Then the PM4 sources, for finer particles that are involved in industrial processes, like sand and gravel, unpaved roads, dusty areas. PM4 includes silica, SiO2, which is what’s being analyzed by the new monitor that was installed last fall that filter-based monitor here at the Yoder station,” Paulson said. “Them PM2.5, even finer, from whether it’s power plant emissions, or vehicle emissions, or again, smoke from fire, is kind of what I always associate PM2.5 with. Again, we have a different continuous BAM monitor that was installed in September of 2022 to monitor for that.”

In going over the objective, Gagen explained why the DEQ is monitoring the ambient air quality in Yoder.

“This was kind of a review of the monitoring objective and what equipment we have out there. Leif [Paulson] kind of went over it and basically how we ended up here. We had some concerns from the town about being impacted by the PM, so we came up with a PM10 continuous BAM and a PM2.5 continuous BAM just to start getting some data to see if we could see what was going on, if the town was getting impacted. That’s the first step. Then another concern later on, after we were going the PM10 and 2.5, was the concern for the PM4 silica. So, that was a new sampler that the division has never ran. So, we got that figured all out.”

Gagen expressed DEQ technicians had done a good job keeping the monitors up and running. 

“This just kind of sums up a lot of what Leif [Paulson] was talking about,” Gagen said flipping the slide. Then this is just kind of a breakdown. So, as we started monitoring, we started learning stuff and we found additional stuff that would be useful. One of them that we found was the PM4 speciation. So, we could kind of see where, if we were getting impacted, where that might be coming from. So, the speciation gave us something other than total PM10 or total 2.5, so you could look a little closer. Then, in 2023, we installed wind speed and wind direction. We did have, if you look at our website right now, there’s a note on there that says, ‘Hey, we’re reporting wind speed and wind direction, but we’re not 100% sure of the accuracy of it. We have another one. The same type of wind sensor at a different facility or another monitoring site. We haven’t had any problems with it. We’ve been trying to work with the manufacturer to figure out how can we look at this. Is this good data?” Gagen explained.

“When I mean it, it seems goofy. There’s been times when we’ve looked at it internal and we see really high winds and we’re like, I don’t know if that wind was that high winds and we’re like, I don’t know if the wind was that high.”

Gagen later commented the wind speed was registering 142 miles and hour. 

“Even by Wyoming standards, it’s a little windy,” Paulson joked.

“What we are trying to do, too, is when we were talking with the manufacturer, trying to figure a way to audit this. It’s not like a wind speed, wind sensor that you can get at the airport. It’s not that high quality but it gives us a general direction or indication of wind speed and direction where it’s going. So, we’re in the process of figuring a way to do some additional QA audits on that. But we’re hoping to get that taken care of. But if you do look, and the reason we have that message on the website is because we were reporting it and then we said, ‘I don’t know if that’s right’ or we didn’t have trust in it,” Gagen explained. 

The DEQ pulled the wind monitor information off their site since it appeared to be inaccurate however community members who monitor the DEQs Yoder reporting site. 

“So, we pulled it off and then I got a couple of calls saying, ‘Where’d that data go?’ and I figured it was better to put it back up and put a note and say, ‘Hey, this is what’s going on,’ just a note here,” Gagen explained. 

The technical discussion continued on for some time before Nancy Vehr, Wyoming DEQ Administrator gave a brief summary to the community. 

“I’ll just start off first with the air quality folks. These are all of the scientists and engineers that work on air quality so they know the technical information. I’m not a technical expert. And so, when I hear the information, I try to put it in context for how I understand it so that I can explain it to people,” Vehr explained. “They talked about PM10 the PM 10 size, the four size and the 2.5 and so I’ll start first with the 2.5 size. That what I heard and saw from your data was that there were three exceedances all attributable to wildfire smoke. Everything else was below the health-based ambient standard. So, to me, that’s really good news.”

“For the PM2.5, which is the smallest particles that can be breathed in, the standard and health-based standard is being met. When I think about what, with Yoder coming and brining this concern to us, which we really appreciate because this is what we’re here for – to help all the citizens of the state of Wyoming. When we heard that there was a concern about what people were breathing and being exposed to in terms of PM in the area, according to the information we’ve got for this, I’ll call it a little over [a] two-year period, the PM2.5 health-based standard is being met,” Vehr said. “The elevations that we had were when there were wildfire smoke impacts. So, I take it as a good thing. The next level was on PM4. PM4, we just did for that three-month window. There is no national standard but what they looked at on PM4 was the silica levels that are breathed in. Because that’s what people were concerned about.”

According to Vehr, the PM4 levels met standards too. 

“What I saw from that information is that as MP2.5 or PM10 levels rise, silica kind of tends to go along with that rise but it was below the level of the Texas-based air monitoring concentration values,” Vehr continued. “So, when I see that, that means that it looked like there was a fairly comfortable margin going along. So, that’s the other part that from the PM4 as well as the speciation that looked at the silica. It is below at least the Texas health values which we looked at comfortable margins of safety. That to me, is other good news.”

Moving on to PM10, Vehr noted there were exceedances.

“The third thing that we looked at was PM10. The PM10 monitoring, we have19 days within that little over two-year window where we had exceedances and those are what we’re focused on. Trying to say, ‘Hey, it would be good if we can get those so we have fewer of them, that would be a good thing. We want to continue to look at and address the PM2.5 and the PM4 for what we looked at nothing of concern that we saw there. The PM10, where we had those elevated levels, we want to continue to look for those.” 

The meeting then wrapped up with a short question and answer session from the members of the audience where it was noted a monitoring system should be placed closer to Southeast Schools.