CLARK COUNTY AIR QUALITY FORUM

Clark County PMClark County PM1010

Saturation Study Saturation Study

Rodney Langston, Clark County DAQEMJuly 11, 2006

Overview

• Objectives of the Study

• Selection of PM10 Measurement Methods

• Saturation Sampling Network

• Quality Assurance of Measurements

• Saturation Study Observations

• Overall Results and Recommendations

Objectives

State Implementation Plan committed to a

PM10 saturation study

• Assess the representativeness of the current monitoring network

• Determine the inter-basin and intra-basin transport during high wind speed events

• Determine the neighborhood impacts of major sources in the region

DAQEM Sampling Network

Combined Sampling Network

Saturation Study Observations

• Historical observations• Observed climatology and meteorology• Saturation network versus DAQEM

network comparisons• High wind speed events

Historical Observations

0

1

2

3

4

5

6

Da

ys o

f E

xce

edan

ces

W 0

0

Sp

00

Su

00

F 0

0

W 0

0/01

Sp

01

Su

01

F 0

1

W 0

1/02

Sp

02

Su

02

F 0

2

W 0

2/0

3

Sp

03

Su

03

F 0

3

W 0

3

Historical Observations

0

50

100

150

200

% o

f N

orm

al P

rec

ipit

ati

on

1999 2000 2001 2002 2003 2004 2005

9 4 3 11 4 2 1# of Exceedances

Historical Observations

Effect of wind speed on exceedance values2000 – 2003 data

0

100

200

300

400

500

600

0 5 10 15 20 25 30 35

24-Hour Average Wind Speed (mph)

PM

10 E

xc

ee

da

nc

e V

alu

e (

g/m

3 )

0

20

40

60

80

100

120

140

160

180

200

4/15/05 4/29/05 5/13/05 5/27/05 6/10/05 6/24/05

(ug

/m3)

Study Observations

24-hour average DAQEM network PM10

May 9

May 16

May 29

June 17Fires

0

20

40

60

80

100

120

140

160

180

200

4/15/05 4/29/05 5/13/05 5/27/05 6/10/05 6/24/05

(ug

/m3)

Study Observations

24-hour average saturation network PM10

May 9

May 16

May 29

June 17

Fires

High Wind Speed Events

0

50

100

150

200

250

300

5/28/05 0:00 5/29/05 0:00 5/30/05 0:00 5/31/05 0:00

PM

10 (

ug

/m3)

0

5

10

15

20

25

30

Co

mp

osi

te W

S (

mp

h)

Hourly saturation network PM10 values

High Wind Speed Events

Hourly saturation network PM10 values

0

50

100

150

200

250

300

6/16/05 0:00 6/17/05 0:00 6/18/05 0:00 6/19/05 0:00

PM

10 (

ug

/m3)

0

5

10

15

20

25

30

Co

mp

osi

te W

S (

mp

h)

Study ResultsAdequacy of DAQEM Network

• 24-hour average PM10 levels relatively low

• High wind speed events could have produced exceedances in prior dry years

• DAQEM network reflected observed patterns in the historical analysis

• Saturation network saw similar patterns but added higher values in the south

Concentration distributions for “high-PM days” were evaluated

Network ObservationsMay 29, 2005

SaturationDAQEM

Network Observations June 17, 2005

SaturationDAQEM

Study ResultsTransport During High Wind Events

• Four high wind speed events• High wind speed events could have produced

exceedances in prior dry years• June 17 event reflected southwest to

northeast axis with apparent transport

Composite June 17, 2005

Saturation and DAQEM Networks

Study ResultsNeighborhood Impacts

• Two sites adjacent to major sources– West side near quarry – Mountain Crest– Northeast side near quarry – Speedway

• Influence of the sources could be seen at the adjacent sites in stable conditions (10-20 ug/m3)

• Source contribution in high wind speeds will be related to the source mitigation efforts

Study Average PM10 by Hour

0

15

30

45

60

0:00 6:00 12:00 18:00

Ave

rag

e P

M10

(u

g/m

3)

0

15

30

45

60

0:00 6:00 12:00 18:00

Hour of the Day

Ave

rag

e P

M10

(u

g/m

3)

MountainCrest

Wetlands

Blue Diamond

Summary

• Additional site in the south for inflow and observations during high wind speed events

• Review the status of the west side sites• ~15 mph wind speeds needed for entrainment• Material handling added 10 to 20 ug/m3 to

regions adjacent to quarry sites• Optical method worked well but with some

limitations • Observed PM10 higher values were short lived due to

limited PM reservoir• Field observations of dust mitigation appeared

very effective in reducing visible emissions

Questions and Comments

Please contact: Rodney Langston

(702) 455-1661

Department of Air Quality and Environmental Management (DAQEM)