Low-concentration open-path DOAS for ambient air quality monitoring.
The AR500 series measures several gases at once along a path of 100 to 1000 m. The analyser sits indoors and is connected to the emitter and receiver by optical fibre, so only light crosses the measured air.
Emitters and receivers are available as separate units (ER110, ER120N, ER150) or as a combined unit with a retro-reflector (ER120 with RR090). The choice depends on path length and mounting conditions. One analyser can serve several paths through an optical multiplexer.
| Measurement principle | UV-DOAS / FTIR-DOAS |
| Light source | Xenon lamp (broadband) |
| Measuring path | 100–1000 m |
| Gases | SO₂ / NO₂ / O₃ / BTEX / NH₃ / HCHO and others |
| Interfaces | 4–20 mA / RS232 / RS485 / Ethernet |
| Certification | TÜV QAL1 · MCERTS · EPA · CCEP |
Typical data from OPSIS product documentation; specifications depend on the application and are confirmed at quotation stage.
Which gases can the AR500 series measure?
SO₂, NO₂, O₃, BTEX, NH₃, HCHO and other UV-visible absorbing gases, several of them simultaneously from one analyser.
What path length is needed?
Between 100 and 1000 m depending on the required detection limit and the site layout.
Send the gases, ranges, duct or path dimensions and required certification — we will respond with a technical proposal.