1. Environmental Initiative
Duluth Air Quality Dialogue
May 2, 2012
Up in the Air: What Changes in
Federal Air Quality Standards
Could Mean for Minnesota
A Northern Minnesota Perspective
Progress and Challenges
Michael G. Cashin, PE
Minnesota Power (ALLETE)
mcashin@mnpower.com

2. Northern Minnesota
Enjoys Good Air Quality
• Excursions in air quality degradation are
associated with transport of emissions from the
South and Southeast
• Occasionally, natural events like forest fires
exhibit effects
• May through September is the typical season for
excursions
• Emissions loading in Northern Minnesota and
Minnesota in general has been greatly reduced
over the last twenty years
• Further emissions reductions are planned, helping
assure continued good air quality

3. Northern Minnesota
Enjoys Good Air Quality
Ground level air quality monitors confirm good air quality
• Ground level monitor: 3 consecutive years analyses are
needed to make a proper NAAQS Attainment
Determination
• Monitors have shown a history of good air quality in
Northern Minnesota
• Scarcity of monitors in some areas suggests modeled
attainment (requirement rescinded by EPA).
• Use of Modeled air quality overstates degradation
relative to ground level monitors (ref. Atlanta area study)
• Modeling false nonattainment hits confuse effective
resource deployment. Risk wasted $$ better applied ??

4. Conditions Vulnerable to Air Quality Degradation
Thermal Inversions Concentrate Pollutants. Transport Raises Background

5. Sensitivity of the general population matters
The Air Quality
Index tool allows
developing air
quality
degradation to
be tracked and
warnings issued
to sensitive
group if
conditions so
warrant.
Sensitive Group
Varying sensitivities to
exposure challenges EPA
when updating NAAQS.
http://www.airnow.gov/index.cfm?action=airnow.main

6. NAAQS: Set at a level protective of human health and
welfare with a margin of safety
Death (eventually, life
Statistical uncertainty expectancy is 78.1 years)
when trying to
measure low level Smoking: Extra chance of cancer death
(life expectancy shortened avg. 14 years, 19% are
risks impedes smokers, > half die prematurely, ref. CDC)
accuracy (e.g. isolate Margin of Safety
confounding factors) USEPA regulates so risks
Equivalent to one person in fall in or below this range
the USA (1 in 312 Million)
One person in the One in a
world (1 in 7 Billion) Million
Reference: Dr. John Paling, Risk in Perspective , Paling Perspective Scale

7. MP SO2 and NOx emission rates
M i nne s o t a
P o w e r
C o a l
U ni t
E mi s s i o n
R a t e s
O v e r
T i me
Minnesota Power is
2.000
1.800
trending with other 1.600 SO2
NOx
1.400
Minnesota sources 1.200
1.000
towards lower emissions 0.800
0.600
0.400
0.200
0.000
1980
A ctual 2000
A ctual 2010
A ctual
We i g h t e d
A v e r a g e
E mi s s i o n
R a t e
Minnesota EGU NOx emission rates MN EGU SO2 emission rates
NOx Emissions and SO2 Emissions and SO2
Average Input-based NOx
100,000
100,000 Output-based Emission Rates
0.6 100,000
120,000 7
90,000
Emission 0.5 100,000 from Minnesota Electric
lb/MMBtu energy input
6
80,000
Rate from Minnesota Generating Units
70,000 5
EGUs 0.4
80,000
60,000
Tons tons
lb/MWH
tons
50,000 0.3 4
Tons
60,000
short
40,000 to 3
0.2 to
30,000 40,000 lb
20,000 2
0.1
10,000 20,000 1
0 0 0
1995 2000 2005 2010 0- 0
1995 2000 year 2005 2010 1995 2000 2005 2010
1995 2000 2005 2010
year

8. Diversifying MP Energy Sourcing, 2005 through 2024
Minnesota Power Generation 2005 Retrofit of Emission Controls,
Minnesota Power Generation in 2013
Expanded Conservation, Diversification
MP Hydro
4% of MP Energy Sourcing:
3% Good MP environmental performance
MP Hydro Biom ass
4%
Coal
Biom ass history and continuous improvement
75%
1%
95% Coal Wind
planned going forward.
95% 13%
Manitoba
Hydro
Purchase
MP Energy Sources in 2024
5% Latest Integrated Resource Plan
Market
MP Energy Sources in 2012 Purchases
Expanded 8%
Conservation
Market Purchases
1%
11%
Manitoba Existing
Manitoba
1%
Coal LongTerm Coal
MHEB ShortTerm
75% 11% 53%
1%
Wind
6%
75% 53%
Hydro Wind
4% 21%
Biomass
2%
Hydro Biomass
4% 2%

9. Monitoring network documents air quality
Duluth SO2 Monitor terminated after 2010 data collected.
International Falls SO2 one year monitoring is planned.

10. Duluth s SO2 Air Quality Monitor (Torrey Building)
In Service for 2010 CY Only
2010 SO2 Monitor, One Hour average Highest Values
Start Sample Value
Month Date Time (ppm) Sample
Value
(ppb) Count#
December 20101215 9:00 0.024 24.00 1
May 20100520 15:00 0.015 15.00 2
January 20100109 15:00 0.01 10.00 3
2010 4th January 20100123 18:00 0.009 9.00 4 12% of NAAQS
Highest
April 20100428 14:00 0.009 9.00 5
Daily Max
May 20100528 13:00 0.008 8.00 6
June 20100602 12:00 0.008 8.00 7
June 20100603 11:00 0.008 8.00 8
April 20100406 14:00 0.007 7.00 9
2010
Average 0.15
2010
Maximum 24.00
Primary 1-hour SO2 NAAQS is 75 ppb, calculated as the 3-year average
of the 99th percentile of 1-hour daily maximum concentrations
This equates to the "high 4th high (H4H)" value …
the 4th highest daily max 1-hour concentration in a year

11. 1-Hour SO2
Twin Cities
< ½ the SO2 NAAQS
1-Hour SO2 Monitors
show real Minnesota
NAAQS attainment.
Going forward,
the Twin Cities
is the focal
point for SO2
Monitors
Role of Modeled Attainment?
EPA has rescinded modeled
1-hour SO2 attainment for
initial designations.
Stakeholder hearings underway.

12. Five Year Wind Rose, 2006 through 2010
Duluth Sky Harbor Airport
2010 SO2 Monitor
Duluth, December 14-15 2010

13. Twin Cities area air quality impacts Duluth during
Duluth s air quality excursion periods.
Duluth, December 14-15 2010
Wind Speed
5 1/2 to 13
kilometers/hour
1 knot = 1.85 kph
or 1.15 mph
50 km

14. Moving Forward
We will ensure a regional energy supply that is:
• affordable,
• reliable,
• reduces environmental impact
and
• promotes a competitive business
environment and an exceptional
quality of life.