HighLight Heading
June 2002
Managing man-made environmental hazards proves challenging
Do we have an air-pollution problem in the Twin Cities?
We do, according to Jim Hensel, an engineer with the Minnesota Pollution Control Agency. Hensel reported his findings May 22 during the research conference breakout session "Waste Recycling Evaluation and Air Quality Metrics."
The panel presentation also included University of Minnesota mechanical engineering professor David Kittelson, who discussed his research on nanoparticle emissions on Minnesota highways, and David Belluck, from the Minnesota Department of Transportation’s environmental services division. Belluck outlined Mn/DOT’s streamlined hazard evaluation process for recycling waste, while his MnDOT colleague, John Sampson moderated the afternoon panel.
Ozone threatens local air quality
Hensel recounted four surprise episodes last summer that have raised serious concerns about the state’s air quality as well as worries over possible increased federal regulation and the steep expenses associated with compliance. The occurrences involved some of the worst ozone levels ever documented in the region.
Ozone is the main pollutant in smog. Sources of ozone include emissions from transportation systems, power stations, and other smaller stationary sources, such as homes and businesses.
Since it is not clear whether last year’s episodes are simply the result of an unusual confluence of weather conditions and other factors, or a trend likely to continue, the MPCA has recommended further monitoring.
Ironically, though violating federal standards would invoke much stricter federal controls, Hensel observed, such conditions would also garner much of the funding needed to deal with the problem—money currently unavailable because Minnesota has yet to reach the federal threshold of "nonattainment." Nevertheless, the MPCA has stepped up efforts to reduce toxic emissions and promote the use of alternative fuels, more efficient vehicles, and mass transit.
High ozone levels can make breathing difficult for certain people, including elderly, children, adults active outdoors, and those with asthma and bronchitis. Ozone can also cause eye irritation and put added strain on the heart. Staying indoors and avoiding exertion, however, can provide relief for at-risk people during ozone alerts.
To keep ozone levels down, experts recommend that people avoid unnecessary car trips, use public transportation, limit the use of gasoline-powered lawn equipment, avoid excessive engine idling, and other measures.
Kittelson’s nanoparticles
In the vein of reducing harmful engine emissions, Professor Kittelson, in a project sponsored by Mn/DOT, has found high concentrations of ultrafine and nanoparticles over urban Minnesota freeways using a mobile aerosol lab. The particles, much smaller in mass than those identified in current emissions standards, raise new health concerns because they elude most existing filtration systems and, when inhaled, deposit themselves in deep-lung tissue.
"By our standards," Kittelson said, "fine particles are boulders."
Kittelson suggested the tiny particles may play a part in causing asthma, heart attacks and cardiovascular disease, or increased hospital admissions for other reasons.
What’s more, ultra-fine and nanoparticles can be tough to measure in the laboratory. "It’s not in the tailpipe, but it’s there when you breathe it," Kittelson said.
In addition, concentrations of nanoparticles are inversely related to road congestion—high-speed, free-flowing traffic produces higher concentrations. The particles "nucleate" most effectively in lower temperatures and quickly bunch up downwind of their source, but then they dissipate rapidly, too. Consequently, roadside joggers, bicyclists, and pedestrians, as well as professional drivers who spend a lot of time busy highways, are most at-risk.
"We know how to clean these things up," Kittelson said, citing refinements to engines and fuel composition as possible solutions. "Nobody wants to spend the money."
Assessing recycling risks
Stephen R. David, an engineer with HDR, joined Mn/DOT’s Belluck, a toxicologist, to discuss their process for using recycled waste materials in construction projects. Mn/DOT developed the process in response to a lack of uniform policies and procedures to assess the possible hazards lurking in recyclable material.
"You’ve got to know what you’re doing and you’ve got to know before you do it," Belluck said.
Neither public policy nor even permits, he added, preclude personal liability for problems with waste. As a result, the department’s environmental services division developed a fact-based, streamlined, systematic process to comply with laws and protect the health and welfare of the public.
Still, David emphasized that the process "is not a replacement for a comprehensive risk assessment" that should also be conducted as a regular part of any project.