Description

This section provides an overview of the hybrid open‑path and MAX‑DOAS concept used by the OPC‑VIS‑LED‑300.

Hybrid DOAS concept

The Airyx OPC‑VIS‑LED‑300 is a hybrid open path DOAS instrument. It combines active open‑path DOAS and passive MAX‑DOAS in one compact system. As a result, it supports long‑path concentration measurements and vertical profiling in a single device.

Multi‑path open‑path mode

In active mode, a 450 nm LED and retroreflectors create a defined optical path for NO₂ and Glyoxal measurements. Meanwhile, the motorized UV telescope can switch between several reflectors, enabling tomography, fence‑line monitoring and spatial coverage without manual alignment.

Passive MAX‑DOAS mode

In passive mode, the instrument retrieves vertical profiles of NO₂, H₂O, Glyoxal, HCHO, HONO, O₃, O₄, SO₂, IO, BrO and OClO. Therefore, it supports a wide range of atmospheric and air‑quality applications.

A temperature‑stabilized spectrometer (300–550 nm, FWHM < 0.5 nm) ensures precise spectral data. In addition, the stable optical design supports accurate retrievals in both active and passive operation.

Thanks to its IP64 housing and internal heating, the OPC‑VIS‑LED‑300 performs reliably in demanding outdoor environments. Consequently, it is suitable for both short‑term campaigns and long‑term monitoring. Moreover, combining two measurement modes in one instrument reduces equipment complexity in the field.