Regional Air Quality Modeling

Patrick Barickman, Air Quality Modeler

Tyler Cruickshank, Meteorologist/Modeler

Utah Department of Environmental Quality

Division of Air Quality

October 23, 2003

Visibility Science, Modeling, and the Western Regional Air Partnership

1977 Clean Air Act Amendments• PSD (new, modified sources)• Visibility Protection Program (existing sources)

1990 Clean Air Act Amendments• Regional Haze• Visibility Transport Commissions

Address haze and visibility in all the national parks• GCVTC

1996 GCVTC Recommendations Published

1997 WRAP Established to implement the recommendations andAssist the States in creating the Regional Haze Plans

GCVTC Recommendations are also the major issues addressedin Utah’s Regional Haze State Implementation Plan due 12/31/03

• Pollution Prevention•Clean Air Corridors•Stationary Sources – regional targets for SO2 emissions•Sources of pollution in and near the Parks•Mobile – automobile emissions•Road Dust – research on the characterization and effects•Emissions from Mexico

Uniform Rate of Reasonable Progress Glide PathGrand Canyon NP - 20% Worst Days

12.0011.66 10.83 9.99 9.15 8.31 7.47 6.97

0

5

10

15

20

25

30

1993 1998 2003 2008 2013 2018 2023 2028 2033 2038 2043 2048 2053 2058 2063

Year

Haz

ines

s In

dex

Uni

t:Dec

ivie

ws

Glide Path Natural Visibility Conditions Observation

Visibility

Light,Waves, Energy, radiation, photons – all the same.

Our eyes see only a tiny fraction of the full radiation spectrum.The radiation spectrum is defined by wavelength.

Our eyes see different radiation wavelengths as color.

Radiation (light) interacts with particles …

• 3 General particle size ranges in our atmosphere …

• Accumulation size particlesstay in the atmosphere for along time.

• Note, that the accumulationsize corresponds to the wavelength of visible light.

• Smaller accumulation modeparticles close to the wavelengthof blue light.

• Larger accumulation modeparticles close to the wavelength of red light.

Particle size determines the amount of scattering.

Scattering efficiency greatest when particles are the same size as the radiation wavelength.

Coarse Size

Molecular Size

Particles in the accumulation mode do the most scattering.

Less mass but more particles.

More mass but fewer particles.

How small is a Accumulation Mode particle ???

Accumulation Mode

Accumulation Mode Zone

Our Clean Atmosphere – Small particles= Blue Sky

Our Dirty Atmosphere … Larger particles= Grayish Sky

Particles with diameters similar to light wavelengths do the best scattering.

What are the scatterers in our atmosphere?

Molecular Size

Accumulation Size

• Molecular sizes rapidly become accumulation size.

Pollution particles enter into the accumulation mode size.

The eastern United States has bigger sulfate particles due to humidity.

Visibility depends on where you are standing and looking in relation to the sun!

Looks bright white on this side.Looks dark on this side.

Looks the same on both sides.

Low sun angle

High sun angle

• Perceived Air Quality changes during the dayas the sun changes position.

The amount of light reflected from a vista that makes it to your eye determines … VISIBILITY.

• Different geographic regions and seasons have different sizes and types of particles.

Light Extinction

Visibility

Particle Source Regions

VOC24%

NOx19%

SO26%

PM1028%

PM2.511%

NH312%

SO437%

NO37%OC

24%

LAC10%

CM22%

Utility60%Smelters

15%

Others25%

Point 72%

Area 6%

Rx burn 0%On road 2%

Non road 16%

Wildfire 4%

1996 Inventory - 9 Transport States, All Sources

1996 SO2 Inventory

Components of Visibility Degradation on the Colorado Plateau 1989 – 1999 as Measured at 6 Locations ( 20% Worst Days )

459,017 426,795

290,882

115,29378,000

79,388

196,130

137,339

139,729

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1996 2018 Milestone

Others

Smelters

Utility

426,795

290,882

78,000

79,388

137,339

139,729

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

Base Year Milestone

To

ns/

Yea

r

Others

Smelters

Utliity

17% Reduction in Point Source SO2 From 1996 to 2018 Base Year

Point Source SO2 – 1996, 2018 Base Year, 2018 Milestone

21% reduction in Point Source SO2 From the 2018 Base Year to the 2018 Milestone Inventory

Reduction in Electric Utility SO2 = 32%

SO437%

NO37%OC

24%

LAC10%

CM22%

Components of Visibility Degradation on the Colorado Plateau 1989 – 1999 as Measured at 6 Locations ( 20% Worst Days )

20%

25%

30%

35%

40%

45%

50%

55%

Bandelier Bryce Cyn Cynlands Grand Cyn Mesa Verde Petrified

Mean

Variation in Sulfate Contribution to Visibility Degradation During the 20% Worst Days 1989 - 1999

Western Wildfires

0

0.5

11.5

2

2.5

33.5

4

4.5

1994 1995 1996 1997 1998 1999

Mil

lio

ns

of

Ac

res

Bu

rne

d

Bryce Canyon

0%5%

10%15%20%25%30%35%40%45%50%55%

1993 1994 1995 1996 1997 1998 1999 2000

SO4

OC

Canyonlands

0%5%

10%15%20%25%30%35%40%45%50%55%

1993 1994 1995 1996 1997 1998 1999 2000

SO4

OC

Grand Canyon

0%5%

10%15%20%25%30%35%40%45%50%55%

1993 1994 1995 1996 1997 1998 1999 2000

SO4

OC

Mesa Verde

0%5%

10%15%20%25%30%35%40%45%50%55%

1993 1994 1995 1996 1997 1998 1999 2000

SO4

OC

Correlation between wildfireintensity and the SO4/OCcontribution to Bext on the

Colorado Plateau.

SO4

OC

Sources:

1) Introduction To Visibility.

William C. Malm, May 1999

Air Resources Division National Park Service

Cooperative Institute for Research in the Atmosphere http://vista.cira.colostate.edu/improve/Education/IntroToVisinstr.htm

2) Improve: Annual Light Extinction Group 10, 50, 90 http://vista.cira.colostate.edu/DatawareHouse/IMPROVE/Data/SummaryData/RECONBEXT_annual.TXT 

3) Projections Report for the 2018 Base Case Emission Inventory Pechan, May 2002 on WRAP emissions forum page

4) Spreadsheets for various inventory components located on the WRAP Emissions Forum page

5) Interagency situation reports for U.S. wildfires. http://www.nifc.gov/news/nicc.html

6) http://vista.cira.colostate.edu/views/

7) http://www.wrapair.org/