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Technical articles

Condensed summaries of OPSIS technical articles, with notes from our own engineering and service work.

AJOPSIS technical notes are written by our own engineering team from project and service experience. The remaining pages condense technical articles published by OPSIS AB: each keeps the original headline, gives a short summary in our own words, adds a note from our work in China, and links to the full original at opsis.se — the original remains the authoritative text.

AJOPSIS technical notes

Ten Years of Open-Path DOAS in Rome, 1991–2000
A ten-year open-path dataset, and what it says about path averages.
2026-10-29
Total Mercury Monitoring in Cement Kilns: From Hg⁰ to Hgᵗᵒᵗ
Total mercury in cement: the converter is the missing piece.
2026-10-29

Measurement principles

DOAS Explained
The measurement principle behind most OPSIS analysers, in plain language.
2017-11-21
How Does a Gas Analyser Work
Why optical absorption needs no sample line, and what traditional analysers do instead.
2017-11-03
What Is the Difference Between a Gas Analyser and a Gas Monitor
Analyser or monitor: mostly a matter of expectation.
2018-03-15
Let There be Light
The physics underneath every optical gas measurement.
2026-04-27
FTIR-DOAS Technology
The infrared complement to UV-DOAS.
knowledge base
UV-DOAS Technology
Where OPSIS measurement started.
knowledge base

Analyser hardware

Inside the Gas Analyser: the Spectrometer
The grating at the heart of a UV-DOAS analyser.
2021-02-23
Inside the Gas Analyser: the Interferometer
The detour through wavenumbers that gives FTIR-DOAS its infrared resolution.
2021-03-16
Inside the Gas Analyser: the Tuneable Diode Laser
Narrow-band light instead of a broad spectrum: TDLAS in practice.
2021-04-08
Inside the Particulate Monitor: the Triboelectric Method
A probe in the duct, no window, and a signal that depends on the dust itself.
2024-02-23
Inside the Particulate Monitor: Optical Methods
Light that is blocked, light that is scattered, and particles counted one by one.
2024-02-09

Emissions monitoring

Operating Principle of an Oxygen Monitor
Flue-gas oxygen as a combustion indicator, measured two ways.
2018-02-22
Inside the Particulate Monitor: Filter Samplers
The slow, precise method behind every PM10 and PM2.5 number.
2024-01-29
Fence-Line Monitoring: Benzene and Beyond
Measuring at the fence instead of at the stack.
2019-01-17
Continuous Emissions Monitoring of Total Mercury
Total mercury, not just the element.
2018-11-15
Continuous Emissions Monitoring: What, Why and How
The regulatory logic behind a CEMS.
2023-05-05
Cemented Success
Cement: high dust, many gases, one analyser.
2025-09-19
Environmental Monitoring in the Aluminium Industry
Fluoride, magnetic fields and dust: monitoring an aluminium smelter.
2025-10-30
Gas Monitoring in the Chlor-alkali Industry
Measuring chlorine where probes corrode and limits are low.
2026-03-30

Practical engineering

No Need for Redundant Systems
Redundancy as a reflex, and what to compare instead.
2019-09-12
Multiplexed Monitoring — to Be Doubted or Not
One analyser, several stacks — the trade-off behind the saving.
2019-02-28
Instrument Interfaces
The wires and protocols between the analyser and everyone who needs the data.
2023-04-06
Planning for a Gas Monitoring System
The checklist that matters after the instrument is chosen.
2018-01-09
Gas Concentration Units and Unit Conversions
The small print behind every concentration figure.
2023-05-11
Calibration – the Base for Trustworthy Measurements
A reading only means something if it can be compared.
2026-07-07
Uncertainties in Measurements
Adding worst cases is not how uncertainty works.
2023-04-20

Discuss your application

Send the gases, ranges, duct or path dimensions and required certification — we will respond with a technical proposal.

+86-21-52361751info@ajopsis.com