Dr Lisa Whalley (Unit 1 - Leeds)
Dr Katie Read (Unit 2 - York)
Instrument Support Level
Instrument Support Level 1
Manufacturer & Model
Thermo Scientific 49
CEDA Archive Name
42 cm x 21.5 cm x 57.5 cm. 15.8kg
45 cm x 25 cm x 62.5 cm. 18kg
Daily Facility Charge
TECO 49 Series Ozone Analyser
The Model 49 is a powerful, easy-to-use, UV photometric based ozone analyzer which offers increased specificity via its balanced optical system.
User-programmable software capabilities allow selection of the frequency at which internal zero/span activation and instrument calibration checks will occur.
Additionally, field-programmable measurement range settings can be stored in memory for subsequent recall. Extended troubleshooting diagnostics now provide an instantaneous indication of instrument operating parameters, status including Pressure, Flow, DC Supply Voltages, Optical BenchTemperature, Ozonator Power Supply Voltage, and Lamp Voltage.
There are two units available
- Unit 1 – Leeds
- Unit 2 – York
The 49 Series Ozone Analysers are based on the principle that ozone molecules absorb UV light at a wavelength of 254 nm. The degree to which the UV light is absorbed is directly related to the ozone concentration as described by the Beer-Lambert Law:
K = molecular absorption coefficient, 308 cm-1 (at 0°C and 1 atmosphere)
L = length of cell, 38 cm
C = ozone concentration in parts per million (ppm)
I = UV light intensity of sample with ozone (sample gas)
I0 = UV light intensity of sample without ozone (reference gas)
The sample is drawn into the instrument through the sample bulkhead and is split into two gas streams. One gas stream flows through an ozone scrubber to become the reference gas (I0). The reference gas then flows to the reference solenoid valve. The sample gas (I) flows directly to the sample solenoid valve. The solenoid valves alternate the reference and sample gas streams between cells A and B every 10 seconds. When cell A contains reference gas, cell B contains sample gas and vice versa.
The UV light intensities of each cell are measured by detectors A and B. When the solenoid valves switch the reference and sample gas streams to opposite cells, the light intensities are ignored for several seconds to allow the cells to be flushed. The instrument calculates the ozone concentration for each cell and outputs the average concentration to both the front panel display and the analog outputs.
The instrument is calibrated before deployment using a Model 49i-PS Ozone Primary Standard operating in the 0 – 500 ppbV range. The Model 49i-PS uses a dual-cell photometer, the concept adopted by NIST as the principle technology for the national ozone standard. The primary standard is itself calibrated against a certified source annually.
- Instrument Insurance
- This system must be insured by the user for £30K and covers loss, theft or damage to the instrument: damage is that over and above general wear and tear. The system has been designed to be rugged and autonomous. Even so, the end-user must respect the fact that the system is a precision optical instrument that must be treated with great care.
- The user is responsible for the instrument from the time it leaves the AMF to the time it is returned and signed off as in an acceptable operating condition by the IS: this will be done as soon as is possible on its return.
- Public Liability Insurance
- The AMOF is not liable for any damage or injury arising from the deployment or operation of this instrument when unattended by the IS.
- Shipping Expenses
- The user is liable for all costs arising from the shipping of the instrument both to and from a deployment.
- IS T&S
- The user is responsible for coving the travel and subsistence expenses of the IS while attending the instrument.
The system when packed ready for shipping consists of a single box:
- Shipping dimensions: 45 cm (W) X 25 cm (H) X 62.5 cm (D)
- Shipping weight: 18kg
The ozone analyser should be operated from an air-conditioned laboratory. A ¼” sampling line should be located outside the laboratory and secured to the common sampling point, ensuring that no water can enter the line.
- A procedure appropriate to lifting a heavy object should be used when lifting the analyzer. This procedure consists of bending at the knees while keeping your back straight and upright.
- The analyzer should be grasped at the bottom, in the front and at the rear of the unit.
- Do not attempt to lift the analyzer by the cover or other external fittings. While one person may lift the unit, it is desirable to have two persons lifting, one by grasping the bottom in the front and the other by grasping the bottom in the rear.
- Cables and sample tubing kept away from pathways; held overhead height if necessary.
- Walkways kept free of clutter and access to exit kept clear.
- Check ozone analyser casing and cables are in good condition before switching on.
- Attach all cables to before switching on at the mains.
- All equipment electrical safety tested.
- There is no requirement for the system to be attended during operation from a safety standpoint.
- Not applicable.
When unpacked the instrument has the following physical specification
- 42 cm (W) X 21.5 cm (H) X 57.5 cm (D)
- 210-250 VAC @ 50/60 Hz,150 Watts
- 0 min°C to 45 max°C in non-condensing environments
The ozone analyser provides a measurement of ozone concentration in ppbV.
- The instrument produces a range of out files and all are text format.
- The user can download (but not delete) this data from the instrument but it should be noted that this data will not have been quality controlled.
- Data is provided in NetCDF files following the AMOF data standard
- Files contain no more than 24hr of data.
- Instrument name is
- ncas-49c-o3-1 (Unit 1- Leeds)
- ncas-49i-o3-4 (Unit 2 – York)
- The data product(s) associated with this instrument:
- Example data file