charlotte ozone

7/29/2019 Charlotte Ozone

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Within-Week Variability and Long-TermTrends in Traffic, Power Plant Emissions,and Ambient CO, NOy and Ozone for theCharlotte Metropolitan Area

Jennifer L. Perry* and Patrick M. Owens

Department of Chemistry

Winthrop University, Rock Hill, SC 29733

*Current address: Department of Chemistry, Duke University, Durham, NC 27708


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Objectives

Show Charlotte regional growth by trafficvolumes and power plant emissions

Characterize trends in NOy, CO, Hydrocarbon,and Ozone monitoring data

Understand how traffic and power plantemission fluctuations within each week affectpollutant levels


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Type of Data Monitoring Site Selected Data

Traffic Counts

Interstate I-77Jun-Aug, 1990-1997

South Blvd,

Wilkinson Blvd,

Graham St.

May-Sep, 1990-1997

(8-9 AM, 6-7 PM, daily)

Mecklenburg

County Ambient

Air Monitors

Plaza, County Line

O3 : May-Sep, 90-00

CO: May-Sep, 93-00

NOy: May-Sep, 95-00

Hydrocarbons, 95-99

Arrowwood O3: May-Sep, 90-00

Power Plant

Emission Monitors

(CEM)

Riverbend, Allen

Marshall, Buck

NOx: May-Sep, 96-00


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Traffic Locations, Monitoring Sites, & Power Plants


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Regional NOx Sources

1997 Gaston County Power Plant Emissions

12,930 tons (Allen)

3,780 tons (Riverbend)

1996 Mecklenburg County Emissions

17,295 tons (mobile sources) 687 tons (stationary sources)


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Traffic Sites

Roadway Tachograph Loc. Data Available

Interstate 77 SC Welcome Center

Between Exits 88 & 90

June-August 1990-1997

(Hourly data)

South Blvd (Hwy

521)

Between Poindexter &

Marsh @ Pepsi Plant

May-Sept 1990-1998,

(7-8AM, 5-6PM, Daily)

Wilkinson Blvd

(Hwy 29&74)

Remount Rd

Intersection

May-Sept 1990-1998,


Graham St. Past Railroad Tracks

@ 12th St.

May-Sept 1990-1998,



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I-77 Traffic Volume vs. Time of Day

0

1000

2000

3000

4000

5000

Time of Day (Hour)

HourlyV

olume

Sun Mon Tues Wed

Thu Fri Sat


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5

10

15

20

25

30

35

40

1 3 5 7 9 11 13 15 17 19 21 23

Time of Day

Avg

HourlyNOy

Concentration(ppb

)

Sunday Monday Tuesday Wednesday

Thursday Friday Saturday

May-Sep 95-98 Plaza Average Hourly NOy


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May-Sep 93-98 Plaza Average Hourly CO

200

300

400

500

600

700

800

900

1000

1 3 5 7 9 11 13 15 17 19 21 23

Time of Day (Hour)

Avg.HourlyCO

Reading

(ppb)

Sunday Monday Tuesday Wednesday

Thursday Friday Saturday


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1990-1998 May-Sep Diurnal Charlotte Ozone Averages

By Day of Week (weekend days-lines, weekdays-markers


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Day of Week NOx Emissions from Four

Coal-fired Plants near Charlotte

-25-20

-15

-10

-5

0

5

10

15

20

Sun Mon Tue Wed Thu Fri Sat

Day of Week

%Difference

from

7-DayAverage

Allen

Riverbend

Marshall

Buck


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Coal-fired Power Plant Hourly NOx Emissionsby Day of Week for a Recent Season

25.00

30.00

35.00

40.00

45.00

50.00

55.00

0 5 10 15 20

Hour of Day

Da

ilyTons

NOxEmissions

Sun

Mon

Tue

Wed

Thu

Fri

Sat


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Day of Week Variation at Fontana Urban BTEX

Sampling Site

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

Sun-Thu Thu-Sat Sat-Sun

Benzene

Toluene

m/p-Xylene

I-77 Traffic Cts

Day of Week Variation at Kennedy Urban BTEX

Sampling Site

-0.3

-0.2

-0.1

0

0.1

0.2

Sun-Thu Thu-Sat Sat-SunFractionofDifffrom7-Day

Avg

Benzene

Toluene

m/p-Xylene

I-77 TrafficCts

Day of Week Variation in Average Noon to Noon BTEXLevels in Charlotte Aug-Sep 96 and May-Aug 97

Day of Week Variation at Dilworth Urban BTEX

Sampling Site

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

Sun-Thu Thu-Sat Sat-Sun

Benzene

Toluene

m/p-Xylene

I-77 Traffic

Cts


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Traffic Growth for I-77 and SouthBlvd Locations

0

500

1000

1500

2000

2500

3000

3500

4000

1990 1991 1992 1993 1994 1995 1996 1997 1998

Year

Average Hour Traffic 8:00 Traffic 18:00 Traffic

0

1000

2000

3000

4000

5000

6000

1990 1991 1992 1993 1994 1995 1996 1997

Year


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20

22

24

26

28

30

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1995 1996 1997 1998 1999 2000

Year

NO

y

Conce

ntration(ppb)

County Plaza

300

400

500

600

700

1993 1994 1995 1996 1997 1998 1999 2000

Year

CO

Concentration(ppb)

County Plaza

7-9 AM Yearly NOy and CO Trends atCounty Line and Plaza (Gar 00) Sites


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May-Sep Mecklenburg County Ozone Trends

0.04500

0.05000

0.05500

0.06000

0.06500

0.07000

0.07500

1990 1992 1994 1996 1998 2000Year

County Line Arrowwood Plaza


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NOx Emission Trends from the two Coal-firedPower Plants, Allen and Riverbend, near Charlotte

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

June July Aug Jun-Aug May-Sep

AvgTonsNOx/

Day

1996

1997

1998

1999

2000


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Long-term Trends for Allen & RB NOx Emissions,Power, and Emissions per Unit of Power

3000.00

4000.00

5000.00

6000.00

7000.00

8000.00

9000.00

1996 1997 1998 1999 2000

NOxemissions+Gig

aWatt-Hours

2.00

2.50

3.00

3.50

4.00

4.50

5.00

5.50

LbsNOx/Megawatt-hr

Tons NOx emissions GigaWatt-Hours Lbs NOx/Mwt-hr


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95-99 AM Hydrocarbon Reactivity-weightedConcentration Trends for the Plaza Site

0

15

30

45

60

75

90

105

120

135

PAMS Tot. Paraffins Olefins Aromatics

MIR

*Concentration(ppbC)

1995 1996 1997* 1998 1999


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95-99 AM NMOC/NOy Ratios for the PlazaMonitoring Site

0

5

10

15

20

1994 1995 1996 1997 1998 1999 2000

NMOC/NO

y

NOx Limited

VOC Limited


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7-8 AM Within Week Fluctuations for NOy,CO and Traffic Data

0.2

0.4

0.6

0.8

1

1.2

1.4

Sun Mon Tue-Fri SatReading/7DayAverage

NOy CO Traffic


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May-Sep 1990-1998 Within Week Ozone Averages forthe three Mecklenburg County Monitors

0.95

0.97

0.99

1.01

1.03

1.05

Sun Mon Tue-Fri SatReading/7DayAverage

County Line Arrowwood Plaza


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Days Traffic CO NOy Ozone Power

NOx

Su/Tu-Fr 0 0 0 0.3373 0

Mo/Tu-Fr 0.7488 0.9473 0.0381 0.3484 0.0023

Sa/Tu-Fr 0 0.0012 0 0.4683 0.0025

P-Values for Day of Week Comparisons of Traffic,Ambient Pollutants, and Power Plant NOx Emissions


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Conclusions

AM CO and NOy ambient concentrationscorrelate well with observed traffic patterns Weekend AM levels much lower than weekdays

Monday AM CO comparable to other weekdays

Monday AM NOy lower than other weekdays

Within week power plant NOx emissions

Tues-Fri 10% above 7-day average Mon & Sat 7.5% below 7-day average

Sun 19% below 7-day average

Monday AM NOx lowest in week; low Monday AMNO

y

ambient levels may be due to this


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Conclusions

Total Power Plant NOx emissions from Allenand Riverbend Power Plants are stable

From 1996-2000, power generated during May-Sep

by the two Gaston Co. plants increased 27%. From 1996-2000, NOx emissions per unit of power

decreased 20%.

From 1996-2000, total NOX emissions from Allen

and Riverbend increased 4%.


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Conclusions

Hydrocarbon Trends

From 1997-1999, average AM Hydrocarbonslevels at Plaza decreased

The Charlotte metropolitan region appearsto be a VOC-limited area

1995-1999 Plaza AM VOC/NOy ratios areprimarily between four and eight.

Ozone within week variation:

Weekend ozone levels in MecklenburgCounty are equivalent to weekday levels


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RecommendationsFor the city of Charlotte, implement ozone controlmeasures that reduce ambient VOC levels

Replace the use of ozone action days withpractices to be implemented throughout ozoneseason

Evaluate the use of total NOx emissions budgetsfor all power plants in the Charlotte region


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AcknowledgementsNorth Carolina Division of Air Quality (Steve Few, BrianTimin)

Winthrop University students (Gentry Ridgeway and Steve

Hudson)

City of Charlotte Department of Transportation (CharlesAble)

South Carolina Department of Transportation (Joe Boozer)

Duke Energy (Buddy Davis and Kris Knudsen)

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