Air monitors operated by the Minnesota Pollution Control Agency have recorded violations of the state standard for particles in an industrial area of North Minneapolis since 2014. But a newly-released analysis of 2015 data shows heavy metals in the area also are at levels of concern.

The two air monitors, on the west bank of the river near the Lowry Avenue Bridge, recorded lead at higher levels than at other Minnesota locations. In addition, while other metals don't have state or federal standards, chromium, cobalt and nickel were measured at levels above health-based guidelines used by state and federal agencies to set protective levels for air emissions. View the MPCA report of the analysis here: North Minneapolis Air Monitoring Study Data Summary (2015).

“We’ve been concerned about the levels of particles and metals,” said MPCA Assistant Commissioner David Thornton, “but until recently we didn’t have enough data to compare them against health benchmarks for air quality.”

The Minnesota Department of Health reviewed the MPCA’s analysis and expressed concern about the findings. “While the results in this report do not indicate a short-term health risk,” said Environmental Health Manager James Kelly, “we are concerned about the overall impact on air quality in this area and the potential for harm over the long term, particularly for those who work in the immediate area.”

Health concerns related to poor air quality can include respiratory irritation, lung damage, cancer and other health effects. Adults who are exposed to lead can develop cardiovascular problems, and lead is known to cause developmental problems in children. Children are most often exposed to lead in the home from lead-based paint used in older homes.

“The residential neighborhood near this industrial area is known to have a higher rate of children with elevated blood lead levels,” Kelly noted. “The older housing stock in this area, which often has lead paint, is the major source of exposure to lead, however any additional sources of lead exposure should be taken seriously.”

Thornton said the agency has been trying to find out exactly where the pollution is coming from. Northern Metals, a metal recycler, is between the two air monitors, but there are other potential sources in the area as well. The agency has worked over the last year with a handful of the likeliest sources in the area to reduce emissions. He said that while some progress has been made, “It clearly hasn’t been enough. We think there’s more they can do, including signing agreements with us.” To date, none have done so, he said.

Northern Metals in particular has been adversarial, suing in district court to stop the MPCA’s air monitoring. They’re under court order to conduct further testing to determine if the facility is in compliance with its MPCA-issued air emissions permit. But Thornton said the MPCA also recently learned that the company may not have submitted accurate information during the permitting process, and may have changed operations or added new emission sources, or both, without informing the MPCA.

“These are potentially serious permit violations,” Thornton said. “We’ll be looking at all of our options including permit revocation.”

The analysis marks the first time the agency has been able to compare all the data from the two air monitors against standards and health benchmarks. Comparison requires a year’s worth of data, and until recently the agency didn’t have enough data to conduct the analysis. The first monitor was installed in October 2014, the second in June 2015.

Thornton said air monitoring will continue at least until sources of the elevated pollutants have been identified and concentrations reduced to appropriate levels. The lead findings in the analysis trigger a requirement under the federal Clean Air Act to determine if the area is in compliance with the national lead standard. Verifying compliance requires three years of air monitoring data showing lead levels in ambient air below 50 percent of the national standard.