[Federal Register Volume 89, Number 96 (Thursday, May 16, 2024)]
[Notices]
[Page 42874]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-10750]


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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OAR-2023-0642; FRL: 11720-02-OAR]


Update of PM2.5 Data From T640/T640X PM Mass Monitors

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: The Environmental Protection Agency (EPA) is retroactively 
applying the approved modification of the Federal Equivalent Method 
(FEM) designation for the Teledyne Advanced Pollution Instrumentation 
Model T640 particulate matter (PM) mass monitor including the 640X 
option (hereafter T640 and T640X) to all of the concentration data for 
PM with a diameter 2.5 micrometers or smaller (PM2.5) from 
the T640 and T640X monitors in the EPA's Air Quality System (AQS) that 
was reported prior to the modification. The EPA processed the 
unmodified hourly PM2.5 concentration data in AQS using 
collocated or paired ambient temperature when available.

DATES: Updated data will be available in AQS by May 13, 2024. Although 
not required, the EPA recommends that air agencies review the updated 
data by May 28, 2024, and contact their EPA Regional office with any 
questions.

FOR FURTHER INFORMATION CONTACT: Mr. Brett Gantt, Office of Air Quality 
Planning and Standards, Air Quality Assessment Division, Air Quality 
Analysis Group (Mail Code: C304-04), Environmental Protection Agency, 
109 T.W. Alexander Drive, Research Triangle Park, NC 27711; telephone 
number: (919) 541-5274; email address [email protected].

SUPPLEMENTARY INFORMATION:

I. Public Comments

    Because of the importance of this air quality data for regulatory, 
scientific, and public use, the EPA provided an opportunity for the 
public to comment on the EPA's plan to retroactively update the 
PM2.5 data from T640/T640X PM mass monitors (89 FR 11831). 
The EPA received a total of 25 non-duplicative comments. For a summary 
of the comments received and EPA's responses, please see the document 
titled, ``Summary of and Responses to Public Comments on the EPA's Plan 
to Update PM2.5 Data from T640/T640X PM Mass Monitors,'' 
located in the docket for this action at https://www.regulations.gov 
under Docket ID No. EPA-HQ-OAR-2023-0642 and on the EPA's website at 
https://www.epa.gov/aqs/aqs-memos-monitoring-and-policy.

II. Data Update Supplemental Information

    For detailed information regarding the EPA's retroactive update of 
air quality data and how these data may be used, please see the 
document titled, ``Supplemental Information on the EPA's Update of 
PM2.5 Data from T640/T640X PM Mass Monitors,'' located in 
the docket for this action at https://www.regulations.gov under Docket 
ID No. EPA-HQ-OAR-2023-0642 and on the EPA's website at https://www.epa.gov/aqs/aqs-memos-monitoring-and-policy.

Richard A. Wayland,
Director, Air Quality Assessment Division.
[FR Doc. 2024-10750 Filed 5-15-24; 8:45 am]
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