205 Dual Beam Ozone Monitor

Use of two detection cells to improve precision, baseline stability, and response time. 

  • Quiet long-life internal air pump (now standard)
  • Low power consumption (~8 watt)
  • Internal data logger (EEPROM), logs 16,383 lines of data
  • Real-time clock
Read moreShow less

The Model 205 Dual Beam Ozone Monitor makes use of two detection cells to improve precision, baseline stability, and response time. In the Dual Beam instrument, UV light intensity measurements Io (ozone-scrubbed air) and I (unscrubbed air) are made simultaneously. Combined with other improvements, this made it possible to reduce the time between ozone measurements to 2 seconds, making our instrument the fastest UV-based ozone monitor on the market, while still retaining the small size, weight, and power requirements of our popular Model 202 Ozone Monitor. Fast measurements are especially desirable for aircraft and balloon measurements where high spatial resolution is needed. For 10-s averaging, a precision of 1.0 ppb is achieved. Alternatively, one can choose to average more points internally to obtain even better precision. Flash card memory and a long-life, quiet internal air sampling pump are now standard on the instrument. The Model 205 Dual Beam Ozone Monitor has been approved by the EPA as a Federal Equivalent Method (FEM) based on a modification of the Model 202: EQOA-0410-190.

Schematic Diagram



  • Quiet long-life internal air pump (now standard)
  • Low power consumption (~8 watt)
  • Internal data logger (EEPROM), logs 16,383 lines of data
  • Real-time clock
  • Both serial and user-scalable analog voltage outputs (4-20 mA current output optional)
  • Flash card memory (SD card) for virtually unlimited, portable data storage
  • Three 0-2.5 VDC analog inputs for logging other measurements, such as external temperature, pressure, and humidity
  • Convenient user interface to microprocessor, including calibration parameters (gain and zero)
  • Selectable measurement time of 2 s or data averaging times of 10 s, 1 min, 5 min and 1 hr (custom averaging times available)
  • DewLine™ for elimination of any water vapor interference, a unique feature of 2B Tech instruments
  • Dual beam feature allows for heightened precision and improved baseline stability for applications where high spatial resolution is required.


  • GPS for continuous logging of latitude, longitude, and altitude (for 10-s data mode and above)
  • Rechargeable lithium-ion battery provides 12 hours of continuous operation
  • External particle filter
  • Serial-to-USB adapter
  • 4-20 mA analog current output
  • Bluetooth for wireless data transmission
  • Low-temperature package for operation to -20 degrees C (pump, lamp heater)
  • High-altitude upgrade (pressure sensor for use up to 25 km altitude)
  • Extra long-life, low temperature internal air pump
  • Low-power option for even lower power consumption
  • Rack-mount case configuration


The fast, accurate, and precise measurements of the Model 205 Dual-Beam Ozone Monitor--combined with its portability, small size, and versatile data capabilities--have led to its use in many unique and challenging field applications.  Literally from pole to pole and points in between, the Model 205 has been used aboard aircraft, balloons, ships, trains, tower platforms, remote field stations, and others.  The application note here describes the use of a Model 205 on a light rail platform in Utah, resulting in some illuminating (and perhaps counterintuitive) findings about ozone levels near busy highways.  

Download Case Study: Model 205 Used Aboard Light Rail in Utah Air Quality Study


Measurement Principle UV Absorption at 254 nm
Federal Equivalent Method (FEM) Yes, EQOA-0410-190
Linear Dynamic Range 0 to 250 ppm
Resolution 0.1 ppb
Precision (1σ; rms noise) Greater of 1.5 ppb or 2% of reading
Accuracy Greater of 1.5 ppb or 2% of reading
Limit of Detection (2σ) 3.0 ppb (in 10-s measurement mode)
NIST-Traceable Calibration Yes
Measurement Interval 10 s (Data averaging options: 1 min, 5 min, 1 hr)
Flow Rate (nominal) ~1 Liter/min
Flow Rate Requirement >0.6 L/min
Baseline Drift < 2 ppb/day
< 5 ppb/year
Sensitivity Drift < 1%/day
< 3%/year
Measurement Time, Frequency 10 s, 0.1 Hz
Response Time, 100% of Step Change 20 s, 2 points
Averaging Times 1 min, 5 min, 1 hr
Internal Data Logger Capacity 16,383 lines (10-s meas. = 1.9 days; 1-min avg = 11 days; 5-min avg = 1.9 mo;
1-hr avg = 1.9 yr)
SD Card Logger Capacity Minimum 2 GB (> 5-year capacity for 10-s measurement mode)
Ozone Units ppb, ppm, pphm, µg m-3, mg m-3
Pressure Units mbar, torr
Temperature Units °C, K
T and P Corrected Yes
Operating Temperature Range 0 to 50 °C standard; optional -20 to 50 °C with low temperature modifications (pump and lamp heater cold-weather package)
Operating Altitude Range ~0-13.5 km (150-1,013 mbar) standard; optional ~0-25 km (30-1,013 mbar) with upgraded pressure sensor
Power Requirement;
Supplied by battery or 110/220 VAC Power Pack
11-14 V DC or 120/240 V AC, 600 mA, 7.2 watt (6.2 watt with cell heater unplugged)
Size 3.5 x 8.5 x 11 inches (9 x 21 x 29 cm)
Weight 5.5 lb (2.5 kg); 2.8 lb (1.3 kg) without instrument case
Analog Inputs for Internal Logging of Other Instruments 3 Analog Inputs, 0-2.5 V; For example could log external T, P and RH
Data Outputs RS232, 0-2.5 V Analog, LCD Display: (Optional 4-20 mA Current, External USB Converter; request quote)
Data Transfer Baud Rates 2400, 4800, 19200
Output Ranges User-Defined Scaling Factor in Menu
DewLine™ Yes
Quiet Long-Life Internal Air Pump Yes
Flow Meter Yes
Options Battery; External Particle Filter; Serial-to-USB Converter; GPS (for 10-s data mode and above); Bluetooth; 4-20 mA Current Output; Cold-Weather Package (pump, lamp heater); High-Altitude Upgrade; Extra-Long-Life Internal Air Pump; Low-Power Option; Rack-Mount Case Configuration
Upgradable to Model 205 Dual Beam Yes

System Includes

  • Model 205 Dual Beam Ozone Monitor
  • Quiet, Long-Life Internal Air Pump
  • AC Power Adapter (100-240 VAC to 12 VDC) with Country-Specific Plug
  • Cigarette Lighter Adapter
  • Battery Wire Connector
  • Zeroing Cartridge
  • Flash Card Memory for virtually unlimited, portable data storage
  • SD Card (> 2 GB) and SD Card Reader
  • Operation Manual on USB Stick
  • Calibration Data and NIST-Traceable Calibration Certificate
  • Instrument Birth Certificate
  • One-Year Warranty

Industrial Technical Services from Mississauga, Ontario is a single source Instrumentation and Automation company. We provide certified calibrations, PLC programming, custom controls and Panels.

Read moreShow less
Product Details
Contact us
16 other products in the same category:
Spectral Vibration Data Logger. Self contained data logger engineered to measure and record data of accelerations for spectral analysis of vibration and peaks. Includes certificate of conformance.
Integral part of SYSTEM302;Single integrated unit;Functions of interfacing, linking device, bridge, controller, gateway;Fieldbus power supply and distributed I/O subsystem;Connectivity with equipment through...



Contact Form

Create a free account to save loved items.

Sign in