Air Matters, February 2008

Volume 3, Issue 1
Bureau of Air Management
Wisconsin Department of Natural Resources
PO Box 7921
Madison WI 53707

Wintertime air pollution
By Mike Majewski

"Wintertime in Wisconsin"--the expression conjures up images of ice fishing, deep snow cover, cozy fireplaces and clear, cold nights. Unfortunately, we have to include an occasional picture of poor air quality.

Most people associate air pollution events in Wisconsin with ozone during the hot, hazy and humid days of summer. At times, however, the weather conditions during winter can also lead to poor air quality. Prolonged periods of snow cover with cloudy skies and light southerly winds can cause fine particulate matter (PM2.5) concentrations near the ground to increase to unhealthy levels.


Fig. 1 - Normal vertical temperature profile vs. thermal inversion when warm air traps cooler air near the earth’s surface.

This winter, the Department of Natural Resources has issued numerous air pollution advisories around the state due to unhealthy levels of fine particulates. An increase in the number of advisories doesn’t necessarily mean that pollution is getting worse, but that ideal weather conditions were more frequent to cause bad air quality. The weather conditions on December 20 are typical of those that can produce high levels of fine particulates.

On that day, a large area of high pressure was located over the eastern part of the country. Air flow into Wisconsin was from the east-southeast, at speeds generally less than 10 mph. As the day wore on, winds became a bit more southerly, bringing in milder and moist air from the south and southeast. During winter, in Wisconsin and the Midwest, the layer of air near the ground is relatively cold (enhanced by the deep snowpack) compared to the warmer air coming from the south. As the warmer air comes into contact with this cold surface air the moisture is cooled and begins to condense. If enough moisture is present a thick fog layer may develop. As the bottom layer of the advancing warm air mass is cooled, it becomes trapped by a layer of warm air. This creates a vertical temperature profile that is opposite of what is normal (see Figure 1).

This "inversion" also tends to trap pollutants--such as emissions from power plants and cars--near the ground. Additionally, winds from a southeast direction transport air pollution from the Ohio Valley and the Chicago-Gary area into Wisconsin, which adds to the locally produced emissions.

During the December 20, 2007 pollution episode, the Air Quality Index (AQI) at several sites approached the “unhealthy” level with concentrations significantly above the daily fine particle standard of 35 micrograms per cubic meter (ug/m3). Figure 2 is the AQI map for 2 p.m. on December 20. At this time there was unhealthy air quality across southern and parts of western Wisconsin.

Table 1: Number of days when 24-hour PM2.5 average was above 35.5 ug/m3
Table 1. Number of winter days with PM2.5 concentrations above the 24-hour standard of 35.4 ug/m3.

Historically, we can expect about 10-15 days of poor air quality during the wintertime months of December, January and February. Table 1 lists the number of days when the 24-hr average for fine particulate matter (PM2.5) exceeded the standard for the past four winters. The months of February 2005 and December 2007 had the greatest number of days (11 and 10, respectively) with poor air quality.

To find the current air quality in your area, or sign up to receive air quality advisories, please visit http://dnr.wi.gov/air/aq/health/status.asp . For more information on wintertime air pollution, please contact Mike Majewski at 608-267-0577 or Michael.Majewski@wisconsin.gov .

Majewski is a meteorologist with the DNR Bureau of Air Management, Regional Pollutant & Mobile Sources Section, and is located in Madison.

TV program highlights emission reductions at paper mill
By Sarah Murray

A recent Wisconsin Public Television (WPT) program highlighted the efforts of Packaging Corporation of America (PCA) to reduce its emissions of hazardous air pollutants.

Tomahawk Paper Mill biogas production
Tomahawk Mill biogas production facility

PCA’s Tomahawk pulp and paper mill has stayed within its permitted air emissions levels for the past two decades. Ten years ago, in response to a new U.S. Environmental Protection Agency (EPA) standard for hazardous air pollutant emissions, the company began looking at new ways to reduce its air pollution. The method it chose significantly reduces air pollution by capturing pollutants and condensing them into a liquid. The liquid is then piped to a wastewater treatment plant, where anaerobic bacteria digest the material, producing "biogas" that can be used in place of natural gas as a fuel source. PCA estimates that the biogas is saving approximately $1 million a year in avoided fuel costs while removing approximately 1 million pounds of pollutants from the air.

PCA has been a participant in Wisconsin’s Environmental Cooperation Pilot, which gives participating businesses incentives and regulatory flexibility in exchange for superior environmental performance above and beyond state and federal environmental requirements. In 2003, DNR established the Green Tier Program, which is based largely on the results of the pilot program. The WPT program also features an interview with DNR Secretary Matt Frank about the Green Tier Program.

Watch the story from WPT’s January 18 edition of "Here and Now" [exit DNR].

For more information about the PCA mill and its air emissions, please contact Neal Baudhuin, DNR Northern Region Air Supervisor at 715-365-8958; or neal.baudhuin@wisconsin.gov.

Murray is a DNR Communications Specialist and is located in Madison.

Wisconsin Partners for Clean Air solicits nominations for recognition award
By Jessica Lawent

Now is the time to nominate and recognize organizations and businesses that took voluntary actions to improve air quality in 2007. The nomination process is simple and the award provides an excellent opportunity to receive public recognition and media attention.

Last year’s recognition award winners include:

  • Kalahari Resort Convention Center for their comprehensive efforts to reduce energy in every part of their facility.
  • Kohl’s Department Stores for implementing a Green Scene program to reduce energy corporate-wide.
  • Packaging Corporation of America – Tomahawk Mill for their innovative approach of using self-produced energy to reduce emissions and costs (see article above).

This year the awards will be presented on May 22 at the annual Clean Air Extravaganza. Winners will not be announced until the awards event. The intent to apply deadline is March 14th, 2008 and the nomination deadline is March 28th, 2008.

Please visit http://www.cleanairwisconsin.org/partnersmad.php for:

For questions, please contact Jessica Lawent at 414-263-8653 or jessica.lawent@wisconsin.gov.

Lawent is an Air Management Transportation Specialist at the DNR Southeast Region in Milwaukee.

Wisconsin school district earns Energy Star award

The West Allis-West Milwaukee School District was named a 2007 Energy Star Leader by U.S. EPA Region 5. DNR Secretary Matt Frank congratulated the district on earning this distinction. Read Secretary Frank's letter to District Administrator Kurt Wachholz [PDF 26KB].

Remembering EPA Region 5’s Steve Rothblatt

Steve Rothblatt, the U.S. Environmental Protection Agency Region 5 Director of the Air and Radiation Division, died on December 20 after a long fight with cancer. He had been with EPA for over 30 years, serving as the Air and Radiation Director since 2003 after work in enforcement, air management and other EPA programs.

"Steve was a model of optimism," said Air Management Bureau Director Kevin Kessler. "In my short experience he was a friend both personally and a friend of the WDNR. Steve was articulate, pragmatic and always solution-oriented."

"Steve was wonderful to work with," said DNR South Central Region Director Lloyd Eagan. "He was dedicated, hardworking and very smart. He had an unassuming manner, a goofy sense of humor and a very non-threatening personality. Most important of all, Steve was very genuine, easy to work with and a very caring person. Our air quality is better because of Steve's dedication. Many of us are better off because we have known him."

Cheryl Newton is currently serving as the Acting Director of the Air and Radiation Division for Region 5.

 

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Last Review: February 2008
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