City officials are reaching out to the Environmental Protection Agency for outside analysis on some of the million of data points collected through monitors in Evanston’s first air quality study last year.

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City officials collected a wealth of data from a six-month $229,000 study of air quality last year around the Advanced Disposal Waste Transfer site at 1711 Church St.

But to determine whether the pollutants identified in the study pose a public health risk will require further analysis, officials said.

At a final community meeting on the study Aug. 11, Kumar Jensen, the City’s Chief Sustainability and Resilience Officer, said the City is preparing a letter of request to state and U.S. Environmental Protection Agency officials for help in analyzing the data from the study and determine what the City’s next steps should be on the issue.

By going outside, officials recognize that “the data collected can be particularly challenging,” Mr. Jensen said, “and requires, as was mentioned, a lot of validation.

“And we certainly want to make sure that any information we are providing the community with, we feel very confident in what’s being communicated, and part of that is having support from our regulatory authorities,” he said.

In a memo, Mr. Jensen and Ashley Mcilwee, the City’s Senior Environmental Health Practitioner, said that in order to make comparisons between the collected data and federal standards such as the U.S. National Ambient Air Quality Standards (NAAQS) would require a longer term study and a different methodology than what was used.

Mr. Jensen said City staff will also be submitting another letter of request for a mobile formaldehyde monitoring device.

RHP Risk Management Inc., the firm which conducted the study for the City, found significantly higher counts for two of the more than dozen pollutants tested — formaldehyde, which has been classified as a carcinogenic to humans, and nitric oxide, considered a respiratory irritant.

Particularly, with formaldehyde ranking highest in the ranking of the pollutants, “that’s one we want to make sure we’re taking some additional steps on,” Mr. Jensen said.

RHP conducted the study for the City, setting up four monitoring stations around the waste transfer stations and collecting 112 million data points over the six months.

Residents living in the area of the waste station have been pushing for a study for years, complaining of odors and noise coming from the site, which was first licensed as a waste transfer station in 1984.

Advanced Disposal, a national company, operates the station, where private companies drop off waste, much of it construction and demolition debris.

From there, the waste is loaded onto larger trucks and transferred to outside landfills.

The study was funded in part by a settlement in 2016 the City reached in Veolia, the operator of the site before Advanced Disposal.

Veolia agreed to drop its lawsuit, charging the city was trying to drive the company out of Evanston. Some of the settlement money the company agreed to pay the City is being used by Evanston to repair alley near the waste transfer site.

At the Aug. 11 meeting, several residents raised questions about the limitations of the study and asked why it was not designed to address their immediate concerns.

Jerri Garl, a member of Environmental Justice Evanston, the group that played a strong role in the City’s moving forward on the issue, noted that “the report is pretty dense.”

“And while it’s interesting,,” she told Mr. Jensen, “and I’m sure that you know a lot of very useful information can be obtained by further analysis of the existing data set, what we really want to know is, were you able to determine whether or not the waste transfer station is resulting in these air quality issues.

“And it sounds, without looking at other sources of air pollution, you really haven’t been able to answer that question,” she said.

Responding, Mr. Jensen acknowledged that was the case.

He said what the City essentially has is an “ambient air quality study that was specifically focused on trying to answer pretty much one question — which of these pollutants — their presence can be tied or attributed to the operations of the station, and not necessarily their impact on public health or their overall levels.”

Hindsight being 20-20, he said, “if the City were putting together this study, knowing what we know now,” he said, “I think we would have a better idea of what types of questions needed to be asked and what can be determined by the study.

“But we also have to recognize that the study cost a lot of money,” he added, “and that we already pared it down pretty substantially from what the original proposal was to try to get it to a number where we could have something happen at all. We were very fearful if the cost of the study had been much more than it it wouldn’t have been able to happen.”

Betty Ester, a longtime Evanston resident, asked, then, the purpose of the study, maintaining what residents wanted to know, was “whether the waste station was a danger to us.”

Mr. Jensen said, “We believe that this study will help us to answer that question in the future. We hope that we will be able to have that answer sooner than what we’ve been able to have. But we do see this study as a necessary step in being able to answer that question.”

RHP representatives, also taking part in the meeting, noted that their primary goal in the study was to measure for pollutants and then determine whether the waste transfer site was their possible source.

“These are the things we’re asked to look at,” said Jacob Persky, a principal of the firm, speaking at the meeting. “And this is what we believe the evidence shows as the parameters [pollutants] that demonstrate the greatest likelihood of attribution to waste transfer site operations.”

He pointed to some of the study findings, displayed on a chart at the virtual meeting.

The study found significantly higher counts for nitric oxide at two of the sites and for formaldehyde at all four stations.

Formaldehyde has been classified as a carcinogenic to humans since 2004 by the International Agency for Research on

Cancer, the study noted, and nitric oxide as a respiratory irritant.

Results also showed a “statistically significant” difference between the measured ambient air concentrations across operational hours at the waste station and those measured during non-operational hours.

In the company’s final report, RHP officials said the test data can be compared with that coming in through the US EPA stations used across Cook County to monitor regional air quality and other systems in place.

“This will allow an assessment of whether concentrations measured in this study are within the range observed for regional air quality or whether the data represents a “hot spot” influenced by a local emission source such as the waste transfer station,” the study found.

Down the road, longer term monitoring could allow the City to develop a risk assessment for air toxics such as formaldehyde, the study suggested.

At the meeting, Mr. Persky said the data might be used to answer other resident concerns, such as whether a bus parking lot or Tapecoat, a factory in the area, might be a source of the pollutants.

“This study was designed to answer a very specific set of questions regarding parameter prioritization in regard to waste transfer site operations,” he said, “but it is proper to point out that those are two good examples of ways and potential hypotheses to test in the data set to see if the data can tease out other explanations for those observation. So those are great, great observations and great examples of other ways to apply the data set.”