This story was updated at 1:20 p.m. EDT.
The city of Louisville, Ky., will have to invalidate months of air quality data after a U.S. EPA audit identified "severe deficiencies" at the city's agency that monitors air pollution.
The EPA audit on the city's measurements of fine particulate matter, or PM 2.5, comes after a separate audit by the state of Kentucky that also identified flaws in the city's handling of ozone pollution. Both stemmed from technical issues at the Louisville Metro Air Pollution Control District.
It's unclear whether the audits, made public this week, will cause any problems for the Louisville area in meeting federal particulate and ozone standards, officials said. Sean Alteri, acting director of the Kentucky Division for Air Quality, said that as a large metropolitan area, Louisville had previous issues with pollution.
It has met the federal ozone standard -- this summer it also registered as one of the region's best in that regard -- and had requested a reclassification for particulate matter after being identified as out of compliance.
Failing to meet the standards could leave the area at risk of federal fines and greater enforcement.
The audits, Alteri said, did identify a "serious matter" of potentially flawed instruments and data, however. The state will follow up with several more audits on a pollutant-by-pollutant basis, he said, and will work with the city to revamp its monitoring network.
"We'll continue to provide our support in developing and implementing any corrective actions," Alteri said. "There's no disciplinary action. We want to assist Louisville in this."
The findings do raise questions about how the city has handled air pollution monitoring in the past. The federal audit -- which builds on an earlier state investigation into Louisville's PM 2.5 network -- identified "significant issues" with the city's weighing lab, including a lack of review and documentation of certain measurements.
"Staff members were not adhering to the organization's quality assurance procedures and EPA regulatory requirements," the report found. Later, EPA said it was "not confident" in ambient PM 2.5 concentrations calculated at the lab, in part due to a static electric charge from improper electric grounding.
The agency is requiring that data from January 2012 through February 2013 be invalidated, although a review is necessary for data going back further. A follow-up audit will be conducted in 2014, and the agency will continue working with Louisville to "improve its practices," said EPA spokeswoman Dawn Harris Young.
The state audit, which focuses on the city's ozone network, found "multiple data handling issues" and recommends that numerous hours of ozone data be invalidated from a federal database. Procedural deviations and calibration had been uploaded as ambient data, the audit found, and some documentation was insufficient. That will require invalidation of some data, a historical review and better staff training.
It's the second state audit, with several more to come, Alteri said.
The Louisville Metro Air Pollution Control District did not respond to a request for comment and referred questions to the mayor's office. Chris Poynter, a spokesman for Louisville Mayor Greg Fischer, said in an interview that the mayor had hired an independent consulting firm to conduct a report on "what's happened at the air pollution control district, our personnel, our equipment and whether we have the right people in the right positions."
At the completing of that report -- expected in 60 business days -- Fischer would determine the best way to move forward.
Wallace McMullen, co-chairman of the Louisville chapter of the Sierra Club, said the situation was "puzzling" and that he had confidence the city would make the proper corrections.
"We certainly need accurate data and we're supporting that effort," McMullen said. "We don't know very much about what the problems are, but I can't believe that the air pollution control office isn't doing the best they can. The mayor has indicated a strong commitment to getting this situation rectified, and I know there's a strong commitment to clean air for the city."
Click here to read the U.S. EPA audit.
Click here to read the state of Kentucky audit.