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FEM Ozone Module
FEM Ozone Module
Clarity FEM Ozone Module installed on a monitoring pole for accurate outdoor ozone measurement.
Side view of the Clarity FEM Ozone Module mounted on a pole for ambient ozone monitoring.
Front view of the Clarity FEM Ozone Module designed for federal equivalent ozone monitoring.
Clarity FEM Ozone Module air quality monitor mounted on infrastructure for continuous ozone measurement.
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FEM Ozone Module

The Clarity FEM Ozone Module is based on best-in-class technology from 2B Technologies, and provides accurate measurements of ozone in air over a wide dynamic range extending from a few parts-per-billion by volume (ppb) to an upper limit of 100 parts-per-million (ppm) based on the well-established technique of absorption of ultraviolet light at 254 nm.

The FEM Ozone Module integrates seamlessly into Clarity networks with an ozone monitoring technology has been approved by the U.S. Environmental Protection Agency as a modification of Federal Equivalent Method (FEM): EQOA-0914-218. The FEM Ozone Module is well suited for use by states and other monitoring agencies under 40 CFR Part 58, Ambient Air Quality Surveillance, for monitoring for compliance with the Clean Air Act.

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Accurate air quality measurements with Sensing-as-a-Service℠

Sensing-as-a-Service℠ is built for seamless air quality sensor network deployment, data management, and quality control at any project scale. Whether you're a regulator, private company, researcher, or community group, Sensing-as-a-Service ensures delivery of the high-quality air pollution measurements you need to drive real change.

Hardware

Easily deployed air monitoring devices

Solar-powered Clarity Node-S air quality sensor measures PM2.5 and NO2 and serves as a platform for additional modules that measure Black Carbon, Dust, Multi-Gas, Ozone, and Wind.

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Cloud

Cloud data management & visualization

Air quality measurements and air sensor network status are easily accessible in real-time via Clarity’s user-friendly Dashboard, REST API, and OpenMap.

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Support

Expert air quality project support

An experienced Environmental Project Manager to help you define a project plan and guide you through Collocation and Calibration of your devices.

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FEM-Capable Ozone Module Specifications

Specification Detail
Measured pollutant Ozone (O₃)
Sensing method UV absorption at 254 nm, the U.S. EPA reference technique
Regulatory status U.S. EPA Federal Equivalent Method (FEM) designation EQOA-0914-218; suitable for regulatory monitoring under 40 CFR Part 58
Measurement range 0 to 500 ppb at 0.1 ppb resolution
Accuracy ±1.5 ppb below 75 ppb; 2% of reading at or above 75 ppb
Base station Clarity Node-S (externally powered)
Power Under 6 W; mains outlet or optional Clarity external solar power system for off-grid sites
Connectivity Cellular (via Clarity Node-S) at no additional cost
Data delivery Real-time via Dashboard and REST API; default 15-minute frequency
Calibration NIST-traceable; biennial recalibration recommended with periodic zero and span checks through Clarity calibration services
Operating temperature 0 °C to 50 °C (FEM operating window 0 °C to 40 °C)
Dimensions and weight 33.5 × 27.4 × 13.3 cm, 3.94 kg
Deployment environments Ozone attainment monitoring for air and environmental agencies, smog tracking, and school and campus networks

FEM-Capable Ozone Module vs. Low-cost Electrochemical 0zone Sensors

Feature Clarity FEM Ozone Module Low-cost electrochemical O₃ sensors
Sensing method UV photometry, the EPA reference technique Electrochemical cell
Regulatory status EPA FEM designated (EQOA-0914-218) None, indicative only
Accuracy ±1.5 ppb below 75 ppb Indicative only
Cross-sensitivity Low interference from other gases Prone to NO₂ and humidity interference
Long-term stability Stable, with NIST-traceable calibration Drift requiring frequent correction
Data delivery Dashboard and REST API Varies by vendor

FEM-Capable Ozone Module vs. Regulatory Ozone Reference Monitoring Stations

Feature Clarity FEM Ozone Module Conventional regulatory ozone stations
Data grade FEM-capable, suitable for compliance and regulatory use when operated in accordance with FEM guidelines FRM/FEM - the gold standard for accuracy
Footprint 3.94 kg module mounted with the Node-S Shelter or rack-mounted analyzer
Power Under 6 W, with an off-grid solar option AC mains, climate-controlled shelter
Installation Pole-mount, plug-and-play Shelter, professional install
Connectivity Built-in cellular via Node-S Varies; often requires on-site network
Scalability Multiple FEM-capable sites as a network Often only 1–2 sites due to cost
Real-time data Dashboard, API, alerts Often delayed/manual download

Collocation Results: Accuracy and performance testing reports for
FEM Ozone Module

See all performance testing in our Collocation Results Library!

Bakersfield, California

April 1, 2024
-
June 30, 2024
See full collocation results!

Frequently Asked Questions

What is the Clarity FEM Ozone Module used for?

The Clarity FEM Ozone Module is used for high-accuracy, regulatory-grade measurement of ambient ozone (O₃) concentrations. It enables agencies and researchers to collect defensible data for compliance reporting, community exposure studies, and ozone pollution control strategies — particularly where cost or infrastructure limits access to traditional regulatory monitors.

Is the FEM Ozone Module EPA-compliant or certified?

Yes — the Clarity FEM Ozone Module includes a Federal Equivalent Method (FEM)-designated ozone analyzer, meaning it meets U.S. Environmental Protection Agency (EPA) standards for ambient ozone monitoring when operated according to EPA guidelines. This makes it suitable for use in regulatory networks, as well as supplemental and informational monitoring programs requiring high confidence in ozone data.

What makes this ozone sensor different from lower-cost alternatives?

Unlike low-cost electrochemical ozone sensors, the FEM Ozone Module uses UV photometry — the EPA’s reference method for ozone detection. This technology offers superior precision, long-term stability, and much lower susceptibility to cross-sensitivity or environmental interference, making it a trusted solution for compliance-grade monitoring.

How often does the FEM Ozone Module need to be serviced?

While the FEM Ozone Module is more robust than low-cost alternatives, it does require periodic service like zero/span checks and filter replacement to maintain its regulatory-grade accuracy. Clarity provides recommended maintenance intervals and optional Project Support Services to assist customers with calibration, QA/QC, and field servicing as needed.

Can the ozone module be deployed alongside other Clarity sensors?

Yes — the FEM Ozone Module can be deployed in parallel with other Node-S Add-On Modules, including PM, NO₂, and wind sensors. While it cannot be powered by the Node-S air quality sensor due to power requirements, it integrates into the broader Clarity ecosystem for unified data access, visualization, and analysis via the Clarity Dashboard. We offer an external power solution with a solar power and battery backup for remote, off-grid monitoring.

In what environments is ozone monitoring most critical?

Ozone monitoring is especially important in urban areas with high vehicle or industrial emissions, as well as regions prone to photochemical smog formation during hot, sunny weather. It’s also critical in rural downwind locations affected by regional ozone transport. Environmental agencies use ozone data to issue public health advisories, track attainment of air quality standards, and evaluate the success of emissions reduction programs.

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