20211108_NC_DAQ

ROY COOPER
Governor
ELIZABETH S. BISER
Secretary
MICHAEL ABRACZINSKAS
Director
NORTH CAROLINA
Environmental Quality
November 8, 2021
David Miller, P.E.
NC Department of Environmental Quality
Division of Energy Mineral and Land Resources
Mining Section
1612 Mail Service Center
Raleigh, NC 27699
Dear Mr. Miller,
On November 3, 2021, you spoke to Raleigh Regional Office personnel requesting local
fine particle (PM 2.5) data as a resource for the permitting process related to the potential Wake
Stone Corporation - Triangle Quarry expansion located on 222 Star Lane in Cary, North
Carolina. The nearest PM 2.5 monitor is the Beta Attenuation Monitor for PM 2.5 (BAM2.5)
located at the Triple Oak monitoring site run jointly by the North Carolina Division of Air
Quality (NCDAQ) and the United States Environmental Protection Agency (USEPA). The site is
adjacent to interstate 40 (I-40), approximately 3.1 miles northwest of the quarry's current
boundary (3.8 miles west along I-40 from the Harrison Avenue,/ I-40 intersection). The BAM2.5
monitor reports an hourly average, 24 hours a day, seven days a week. The NCDAQ's Ambient
Monitoring Section has provided the most recent three years of validated Triple Oak PM 2.5 data
that has been reported to USEPA's Air Quality System (AQS). A synopsis of that data is listed in
the table below.
24-hr concentrations (midnight to midnight)
measured in micrograms per cubic meter
1-hr concentrations in
m3
m3
Annual weighted mean
98th
Average of
Calendar
Data
Annual
(average of the average
percentile
Annual
the daily
year
completeness
average
for each uarter)
value
maximum
2018
91.0%
7.83
7.91
16.0
-average
7.87
15.45
2019
92.9%
7.90
7.88
14.5
7.94
14.21
2020
95.1 %
6.51
6.52
15.0
6.55
13.27
The PM 2.5 standard uses the annual weighted mean for comparison to the annual
standard (12 µg/m3) and the 981h percentile value for comparison to the daily standard (35
µg/m3). We suggest using both the annual weighted mean and the 981h percentile value for the
24-hour averages so the numbers are comparable to what the standard uses. The average 1-hour
North Carolina Department of Environmental Quality I Division of Air Quality
Raleigh Regional Office 13800 Barrett Drive I Raleigh, North Carolina 27609
919.791.4200 T 1 919.571.4718 F

Mr. David Miller
November 8, 2021
Page 2
values and average daily maximum 1-hour values are also listed. The weighted 24-hour means
and 98" percentile values are directly from the USEPA AQS Design Value Report (report code
AMP480). The 1-hour averages are calculated from AQS data downloaded for each individual
year obtained from the USEPA Outdoor Air Quality Data webpage.
If you have any further questions regarding historical BAM PM 2.5 data, please do not
hesitate to contact the Ambient Monitoring Section.
Sincerely,
R. Patrick Butler, P.E.
Ambient Monitoring Section Chief
Division of Air Quality, NC DEQ
cc: RRO Files
Attachment: AMP480 Design Value Report

User ID: XJLSTEGER
Report Request ID: 1969864
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
DESIGN VALUE REPORT
Report Code: AMP480
GEOGRAPHIC SELECTIONS
Tribal EPA
Code State County Site Parameter POC City AQCR UAR CBSA CSA Region
37
183 0021
PROTOCOL SELECTIONS
Parameter
Classification Parameter Method
Duration
DESIGN VALUE 88101
SELECTED OPTIONS
�—
Option Type
Option Value
WORKFILE DELIMITER
,
SINGLE EVENT PROCESSING EXCLUDE REGIONALLY CONCURRED EVENTS
QUARTERLY DATA IN WORKFILE
NO
AGENCY ROLE
PQAO
USER SITE METADATA
STREET ADDRESS
MERGE PDF FILES
YES
USE LINKED SITES
YES
DATE CRITERIA
Start Date End Date
2018
2020
APPLICABLE STANDARDS
Standard Description
PM25 24-hour 2012
PM25 Annual 2012
Nov. 5, 2021
Selection Criteria Page 1

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY Report Date: Nov. 5, 2021
AIR QUALITY SYSTEM
PRELIMINARY DESIGN VALUE REPORT
Pollutant: Site-LevelPM2.5 - Local Conditions(88101) Design Value Year: 2019
Standard Units: Micrograms/cubic meter (LC)(105) REPORT EXCLUDES MEASUREMENTS WITH REGIONALLY CONCURRED EVENT FLAGS.
NAAQS Standard: PM25 24-hour 2012 / PM25 Annual 2012
Statistic: Annual Weighted Mean Level: 12
Statistic: Annual 98th Percentile Level: 35 State Name: North Carolina
2019 I 2018 I 2017 I 24-Hour I Annual
Site ID / ICred. Comp. 98th Wtd. Cent& ICred.Comp. 98th Wtd. Cert6 I Cred.Comp. 98th Wtd. Cert& IDesign Valid IDesign Valid
STREET ADDRESS IDays Qrtrs Perctil Mean Eval (Days Ortra Perctil Mean Eva! IDays Qrtrs Perctil Mean Eva! I Value Ind. I
Value Ind.
37-183-0021 338 4 14.5 7.9 Y 332 4 16.0 7.9 Y 349 4 18.1 8.5 Y 16 Y 8.1 Y
2826 TRIPLE OAK DRIVE
Notes: 1. Computed design values are a snapshot of the data at the time the report was run (may not be all data for year).
2. Some PM2.5 24-hour DVs for incomplete data that are marked invalid here may be marked valid in the Official report due to additional analysis.
3. Annual Values not meeting completeness criteria are marked with an asterisk ('*').
Page 3 of 5

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY Report Date: Nov. 5, 2021
AIR QUALITY SYSTEM
PRELIMINARY DESIGN VALUE REPORT
Pollutant: Site-LevelPM2.5 - Local Conditions(88101) Design Value Year: 2020
Standard Units: Micrograms/cubic meter (LC)(105) REPORT EXCLUDES MEASUREMENTS WITH REGIONALLY CONCURRED EVENT FLAGS.
NAAQS Standard: PM25 24-hour 2012 / PM25 Annual 2012
Statistic: Annual Weighted Mean Level: 12
Statistic: Annual 98th Percentile Level: 35 State Name: North Carolina
I 2020 I 2019 I 2018 ( 24-Hour Annual
Site ID / ICred. Comp. 98th Wtd. Cert& ICred.Comp. 98th Wtd. Cent& I Cred.Comp. 98th Wtd. Cert& IDesign Valid IDesign Valid
STREET ADDRESS IDavit Ortra Perctil Mean Eval IDays Qrtrs Perctil Mean Eval IDays artrs Perctil Mean Eval IValue Ind. IValue Ind.
37-183-0021 347 4 15.0 6.5 Y 338 4 14.5 7.9 Y 332 4 16.0 7.9 Y 15 Y 7.4 Y
2826 TRIPLE OAK DRIVE
Notes: 1. Computed design values are a snapshot of the data at the time the report was run (may not be all data for year).
2. Some PM2.5 24-hour DVs for incomplete data that are marked invalid here may be marked valid in the Official report due to additional analysis.
3. Annual Values not meeting completeness criteria are marked with an asterisk ('*').
Page 4 of 5

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