Accurate air quality data starts with calibration

Accurate air quality data starts with calibration. Accurate air quality data starts with calibration. Calibration involves tuning your air quality measurement equipment's output to more closely match reference air quality monitor readings. Clarity's rigorous calibration process ensures your air quality measurements are scientifically validated and defensible.

Explore the content below to understand Clarity's calibration options, or head to our collocation results library to see real-world performance quantification data from around the world.

Speak to our teamView collocation results

Choose your calibration approach with Sensing-as-a-Service

Calibration is included free of charge with Sensing-as-a-Service. All Clarity Nodes come equipped with preset standard calibrations — these standard Global Calibrations significantly boost accuracy compared to raw sensor data, even when collocation is not possible. Collocation-Based Calibration further improves accuracy and allows for performance quantification of your air quality measurements. Whenever possible, we always recommend performing collocation, which is the gold standard for optimizing air sensor performance.

Included with Sensing-as-a-ServiceSM

Raw air quality sensor measurements

  • Raw sensor measurements are always available via API and the Clarity Dashboard
  • Provides transparency and traceability of calibrated results to raw measurements
  • Raw data are not recommended for public consumption and are not available on OpenMap

Pre-Calibrated with Standard Global Calibration

  • Enables calibration for improved accuracy even without access to a reference monitor
  • Linear model for PM2.5 provides traceability and minimizes errors related to sensor estimates of aerosol composition
  • Machine-learning based model for NO2 uses advanced statistical methods to counteract temperature and relative humidity fluctuations that affect electrochemical cell sensors

Custom Collocation-Based Calibration (optional)

  • Custom-built calibration for your project means improved accuracy under your specific climatic and air pollution conditions
  • Collocation-based calibrations are transparent and traceable
  • Allows measurement performance quantification for all Nodes, for both PM2.5 and NO2

The Clarity Calibration Process

While pre-calibrated Nodes are available, we recommend that all Clarity devices undergo a rigorous multi-step collocation process in partnership with a dedicated Environmental Project Manager to ensure the best data performance possible.

Global Calibrations Applied

Preset, standard calibrations developed from a dataset of over 6,000,000 measurements are applied to boost accuracy — no initial collocation is required

Onboard Call with Clarity

Define air quality monitoring goals and calibration strategy in collaboration with a Clarity Environmental Project Manager (EPM)

If organisation has access to reference equipment
Collocation with Reference Equipment

Deploy devices alongside a reference monitor for at least one month to gather comparative data

Performance Evaluation

Meet with Clarity EPM to review initial performance results and discuss whether a custom calibration model is needed for optimal performance

If needed depending on local conditions or project requirements

If organisation has access to reference equipment

Optional Custom Calibrations

If you wish, Clarity can analyze collocation data to create a custom, region-specific calibration model for your air quality measurement project

If needed depending on local conditions or project requirements
Field Deployment of Devices

Devices are deployed to the field; when possible, one device remains collocated to monitor calibration accuracy over time

Ongoing Support

Clarity EPM monitors performance and work with you to ensure continued data quality — faulty devices are replaced free of charge under Sensing-as-a-Service

Air quality measurements trusted by organizations like:

Calibration Performance
Evaluation and Reports

Clarity strives to meet the performance targets set by the US EPA, EU, and other regulators for all of our projects.



We openly share calibration reports detailing the performance of each device post-calibration, so you'll know exactly how your air quality sensors are performing relative to strict quality standards. Our Environmental Project Managers also provide guidance to help you make the most of your calibrated data. We want to ensure you can leverage your air quality measurements to drive meaningful insights.

Read third-party evaluation reports from the world’s leading air quality equipment experts on our Resources page.

Why do we calibrate  PM2.5?

Clarity Nodes utilize Plantower low-cost optical particle counter (OPC) sensors to measure PM2.5 mass concentration. OPCs do not directly measure PM2.5 mass but rather count and size particles. To estimate PM2.5 mass concentration accurately, information about particulate composition is needed.

Factory calibration programs an assumed particulate composition factor into each OPC, but this assumption may differ from the actual composition, leading to measurement errors. By analyzing collocation data from various locations, Clarity has developed a generalized calibration profile that reduces these errors.

Through collocation studies at project sites, regional calibration profiles can be developed, further enhancing accuracy by fine-tuning the composition assumptions based on local conditions. Once calibration is completed, both raw and calibrated PM2.5 air quality data are available in the Clarity Dashboard.

Why do we Calibrate NO2?

Clarity Nodes use electrochemical cell sensors (ECS) to measure NO2 concentrations. The ECS reacts with NO2 to generate an electrical current, which is then translated into NO2 concentration.

With ECS sensors, environmental interferences such as changes in temperature and humidity can affect the sensor's baseline and accuracy. Due to the high device-to-device variation of ECS sensors, individual calibration profiles are necessary to minimize measurement errors.

By conducting collocation studies, specific calibration profiles can be created for each air quality sensor, correcting for interferences and adjusting the raw NO2 signal to better match the reference instrument's output. Once calibration is completed, both raw and calibrated NO2 air quality data are available in the Clarity Dashboard.

What else is included with Sensing-as-a-Service℠?

Our patented Remote Calibration is at the core of Clarity's Sensing-as-a-Service offering, which includes:

Hardware -
Hardware

Easily deployed air monitoring devices

Self-powered Clarity Node-S air quality monitoring hardware measures PM2.5 and NO2 and serves as a platform for additional modules that measure Wind, Black Carbon, and Ozone. Rugged and with minimized maintenance requirements, our devices reduce installation and field intervention costs.

Explore our devices
Clarity's user friendly air quality management dashboard - Learn more
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. No matter your level of experience, we have a solution to help you and your project’s stakeholders to get the most out of your data.

Learn more about Clarity Cloud
Dedicated Environmental Project Manager to help you with your Air Quality Management project. Learn more.
Support

Expert air quality project support

Air quality monitoring is hard, but we can help. You’ll partner with an experienced Environmental Project Manager to help you define a project plan and guide you through Collocation and Calibration of your devices. You’ll receive support throughout the duration of your project, with recurring meetings and check-ins to ensure data quality. 

Meet our team

Discuss calibration with an air quality expert

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