6560-50-P
ENVIRONMENTAL PROTECTION AGENCY
[FRL-11978-01-ORD]
Ambient Air Monitoring Reference and Equivalent Methods; Designation of One New
Equivalent Method
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of the designation of a new equivalent method for monitoring ambient air
quality.
SUMMARY: Notice is hereby given that the Environmental Protection Agency (EPA) has
designated one new equivalent method for measuring concentrations of ozone (O3) in ambient
air.
FOR FURTHER INFORMATION, CONTACT: Robert Vanderpool, Air Methods and
Characterization Division (MD-D205-03), Center for Environmental Measurement and
Modeling, U.S. EPA, Research Triangle Park, North Carolina 27711. Phone: 919-541-7877.
email address: Vanderpool.Robert@epa.gov.
SUPPLEMENTARY INFORMATION: In accordance with regulations at 40 CFR part 53, the
EPA evaluates various methods for monitoring the concentrations of those ambient air pollutants
for which EPA has established National Ambient Air Quality Standards (NAAQS). Monitoring
methods that are determined to meet specific requirements for adequacy are designated by the
EPA as either reference or equivalent methods (as applicable), thereby permitting their use under
40 CFR part 58 by States and other agencies for determining compliance with the NAAQS. A
list of all reference or equivalent methods that have been previously designated by EPA may be
found at http://www.epa.gov/ttn/amtic/criteria.html.
The EPA hereby announces the designation of one new equivalent method for measuring
concentrations of O3 in ambient air. This designation is made under the provisions of 40 CFR
part 53, as amended on October 26, 2015 (80 FR 65292).

This new equivalent method for O3 is an automated method (analyzer) utilizing the
measurement principle based on UV photometry. This newly designated equivalent method is
identified as follows:
EQOA-0424-263, “Vasthi Instruments Model Vair-9004 O3 Analyzer,” UV
photometric analyzer operated in a range of 0–0.5 ppm, with 0.5 µm, 47 mm diameter
Teflon® filter installed, operated at temperatures between 20°C and 30°C, with
temperature and pressure compensation, at a nominal sampling flow rate of 800 cc/min,
using a 5 minute averaging time, with either 105VAC-125VAC or 200VAC-240VAC
input power options, 270-watt power consumption, equipped with 7 inch LCD touch
screen display, and operated according to the Vasthi Instruments Model Vair-9004
Ozone Analyzer User’s Instruction Manual.
This application for an equivalent method determination for this O3 method was received
by the Office of Research and Development on April 8, 2024. This analyzer is commercially
available from the applicant, Vasthi Instruments, Guntur 522 001, Andhra Pradesh, India.
A representative test analyzer was tested in accordance with the applicable test
procedures specified in 40 CFR part 53, as amended on October 26, 2015. After reviewing the
results of those tests and other information submitted by the applicant, EPA has determined, in
accordance with 40 CFR part 53, that this method should be designated as an equivalent method.
As a designated equivalent method, this method is acceptable for use by states and other
air monitoring agencies under the requirements of 40 CFR part 58, Ambient Air Quality
Surveillance. For such purposes, this method must be used in strict accordance with the operation
or instruction manual associated with the method and subject to any specifications and
limitations (e.g., configuration or operational settings) specified in the designated method
description (see the identification of the method above).
Use of the method also should be in general accordance with the guidance and
recommendations of applicable sections of the “Quality Assurance Handbook for Air Pollution

Measurement Systems, Volume I,” EPA/600/R-94/038a and “Quality Assurance Handbook for
Air Pollution Measurement Systems, Volume II, Ambient Air Quality Monitoring Program,”
EPA-454/B-13-003, (both available at http://www.epa.gov/ttn/amtic/qalist.html). Provisions
concerning modification of such methods by users are specified under section 2.8 (Modifications
of Methods by Users) of appendix C to 40 CFR part 58.
Consistent or repeated noncompliance with any of these conditions should be reported to:
Director, Air Methods and Characterization Division (MD-D205-03), Center for Environmental
Measurement and Modeling, U.S. Environmental Protection Agency, Research Triangle Park,
North Carolina 27711.
Designation of this equivalent method is intended to assist the States in establishing and
operating their air quality surveillance systems under 40 CFR part 58. Questions concerning the
commercial availability or technical aspects of the method should be directed to the applicant.
Alice Gilliland,
Acting Director,
Center for Environmental Measurements and Modeling.
[FR Doc. 2024-12785 Filed: 6/11/2024 8:45 am; Publication Date: 6/12/2024]