Laboratory bench with test tubes and the air-Q with a VOC PID sensor in the foreground. In the background, a laboratory assistant fills a liquid into a measuring beaker.
Air quality

Measuring VOCs with a PID sensor - What can the air-Q do with the special PID sensor for volatile hydrocarbons?

Volatile organic compounds (so-called VOCs) can be measured in the air-Q using various VOC sensors. Depending on the application, a higher-quality PID sensor can be selected, which also allows precise measurements of individual VOCs in the laboratory or industrial production.

Author:

Mario Körösi

Date:

26.5.2023

VOCs are measured in the air-Q as standard using a resistive sensor. Molecules that "dock" onto the surface of the sensor cause a change in the electrical resistance in the sensor. The measuring principle is tried and tested and very suitable for most requirements. For special applications it is possible to use a PID sensor in the air-Q, which can be used in a free additional sensor slot in the measuring device. We present the air-Q VOC PID sensor and answer important questions about how it works.

PID sensors, or photoionization detectors, play a crucial role in modern air monitoring technology. These sensors are particularly effective when it comes to detecting volatile organic compounds (VOCs) and other potentially hazardous gases in the ambient air. Thanks to their high sensitivity, PID sensors can detect even the lowest concentrations of pollutants that are invisible to the naked eye but still pose significant health risks.

Their ability to provide accurate measurements in real time makes them indispensable in areas such as industrial safety, environmental monitoring and building technology. Companies that rely on PID sensors benefit not only from improved safety for their employees, but also from regulatory compliance and the prevention of costly environmental and health damage. In a world increasingly focused on sustainability and safety, PID sensors offer a reliable solution for monitoring air quality and protecting the environment.

What advantages does a PID sensor offer over other gas sensors?

PID sensors are particularly sensitive and can detect very low concentrations of VOCs and other pollutants in real time. They offer a fast response time and can measure a wide range of organic compounds, making them versatile and effective for air quality monitoring.

How does a PID sensor measure?

PID sensors (Volatile Organic Compounds - Photoionization Detector) are based on the principle of photoionization. The sensor module consists of an ionizing lamp and a detector. The ionizing lamp generates high-energy UV radiation that ionizes gas molecules with a certain energy by extracting electrons from them. The excitation energy can be configured by selecting the ionizing lamp in the PID sensor.

The detector in the sensor measures the number of ions thus generated by electrodes hit by the ionized molecules. The electrical current thus generated can be measured and is proportional to the concentration of VOCs in the air. The air-Q converts this current into a measured value. 

Which VOCs can the air-Q PID sensor detect?

The air-Q PID sensor is capable of detecting a wide range of volatile organic compounds (VOCs). Commonly detected VOCs include:

  • ‍Benzene - Often used in fuels and as a solvent.
  • ‍Toluene - Contained in paints, varnishes and adhesives.
  • Xylene - Also found in paints and varnishes.
  • Styrene - Used in the manufacture of plastics and rubber.
  • Formaldehyde - Used in furniture, building materials and as a preservative.
  • Acetone - A common solvent found in household products and industry.
  • Ethanol - Contained in cleaning agents and disinfectants.

The PID sensor in the air-Q can detect a wide range of VOCs found in various industrial and domestic environments. Accurate detection depends on the calibration of the sensor and the specific operating conditions.

air-Q VOC (PID) sensor for professional measurement of pollutants

How does the measurement with the VOC PID sensor in the air-Q work?

The PID sensor can be purchased as an additional sensor in the air-Q Science or as a separate additional sensor for retrofitting existing air-Qs. On request, we offer sensors with different ionizing lamps with excitation energies of 10 eV, 10.6 eV and 11.7 eV.

As with all air-Qs, data input is available via the air-Q smartphone app for iOS and Android, our air-Q web app and data output via MQTT or CSV data export. Different response factors for the PID sensor can be entered via the configuration in the smartphone app or via a configuration file in order to calibrate or use the sensor for measuring specific VOCs.

The air-Q PID sensor has a measuring range of 0 to 6,000,000 ppb with a resolution of 1 ppb. The UV lamp has a service life of at least 1 year - experience has shown that this is significantly longer. It can then be replaced without having to replace the entire sensor. 

For whom is the air-Q with VOC PID sensor suitable?

The air-Q with PID sensor is primarily intended for professional applications. Due to the quantity of VOCs detected, the very wide measuring range and the high accuracy, it is perfectly suited for use in research and development. It can also be used for industrial purposes, e.g. to monitor the concentration of certain harmful or explosive gases in non-air atmospheres. The monitoring of emissions in the environment, safety in the workplace, the detection of leaks in gas pipes and the monitoring of indoor air quality can also be areas of application.

References

Contributed image: SUWANNAR KAWILA + air-Q/canva.com

additional image: air-Q

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Summary

What is a PID sensor and what is it used for?
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A PID sensor (photoionization detector) is a device for measuring volatile organic compounds (VOCs) and other gases in the air. It is often used in environmental monitoring, industry and occupational safety to monitor the concentration of hazardous gases and ensure that air quality meets safety standards.
How does a PID sensor work?
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A PID sensor works by irradiating the air with ultraviolet (UV) light. This light ionizes the molecules of the gases to be measured, generating a current. The strength of this current is proportional to the concentration of the ionized gases, which allows the sensor to determine the amount of gas in the air.
What advantages does a PID sensor offer over other gas sensors?
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PID sensors are particularly sensitive and can detect very low concentrations of VOCs and other pollutants in real time. They offer a fast response time and can measure a wide range of organic compounds, making them versatile and effective for air quality monitoring.
In which areas are PID sensors typically used?
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PID sensors are used in a variety of areas including industrial process monitoring, environmental emissions control, workplace safety, gas leak detection and indoor air quality monitoring.
What factors should be considered when selecting a PID sensor?
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When selecting a PID sensor, factors such as the measuring range, sensitivity, response time and compatibility with the gases to be monitored should be taken into account. It is also important to consider the ease of use, maintenance requirements and calibration capabilities of the sensor to ensure optimal performance.
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