Nitrogen dioxide (NO₂) is one subtype of a group of pollutants known as nitrous oxides, or NOx, which are highly reactive gases. Nitrogen dioxide gas can harm human health and environmental quality when it enters the air. Nitrogen dioxide can interact with other chemicals in the air and form acid rain, which in turn can damage ecosystems and human-built monuments, structures, and cultural sites. The nitrate particles that result from nitrous oxides such as NO₂ also contribute to haze and decreased visibility. Therefore, the monitoring and treatment of NO₂ is receiving increasing attention from the WHO and most regional air quality management agencies and authorities.

To meet the needs of NO₂ pollutants monitoring and treatment, FPI pioneer launched AQMS-700 CAPS NO₂ analyzer based on the optical cavity attenuation phase shift technology (CAPS) for directly monitoring the NO₂ concentration in the ambient air, and it can be widely used in the online monitoring of the NO₂ content in the ambient air quality monitoring scene.

Principle:

The analyzer measures the gas concentration according to the phase difference between the beam in the reference cavity and the cavity with NO₂. The LED beam is modulated by high frequency signal and coupled into the optical cavity composed of high-reflection mirror. Then beam is reflected repeatedly in the cavity and is absorbed by NO₂ in the cavity. The absorbed beam is collected by the detector after passing through the optical cavity and the optical filter. The detector converts the optical signal into electrical signal, then demodulates it by electrical heterodyne method, and finally obtains the signal with phase information.

Features:

• Adopt ultra-high reflector, low detection limit.
• Direct measurement, without reagent or catalytic conversion.
• Strong system stability, low power consumption.
• Simple structure and parts.
• Strong anti-interference ability.
• Fast response time.

Application:

• Atmospheric background station, urban environment and other conventional monitoring.
• Laboratory ultra-high requirement monitoring.
• NO₂ concentration monitoring in special areas such as hospitals.

If any interest in it, please feel free to visit FPI official online store: online.fpi-inc.com/