Model 205 Dual Beam Ozone Monitor™

EPA Federal Equivalent Method (FEM)

>Model 205 Dual Beam Ozone Monitor

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.

205 dual beam ozone monitor diagram




Measurement Principle: UV Absorption at 254 nm; Dual Beam
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 1.0 ppb or 2% of reading for 10-s average
Accuracy: Greater of 1.0 ppb or 2% of reading
Limit of Detection (2σ): 2.0 ppb for 10-s average
NIST-Traceable Calibration: Yes
Measurement Interval: 2 s (Data averaging options: 10 s, 1 min, 5 min, 1 hr)
Flow Rate (nominal): ~1.8 Liter/min
Flow Rate Requirement: >1.2 L/min
Baseline Drift: < 1 ppb/day, < 3 ppb/year
Sensitivity Drift: < 1%/day, < 3%/year
Measurement Time, Frequency: 2 s, 0.5 Hz
Response Time, 100% of Step Change: 4 s, 2 points
Measurement and Averaging Times: 2 s, 10 s, 1 min, 5 min, 1 hr
Ozone Units: ppb, pphm, ppm, 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: 12 V dc or 120/240 V ac, nominally 650 mA at 12 V, ~8 watt (~7 watt with cell heater unplugged)
Size: 3.7 x 8.5 x 11.5 inches (9.5 x 21.5 x 30 cm)
Weight: 5.8 lb (2.6 kg); 3.1 lb (1.4 kg) without instrument case
Internal Data Logger Capacity:

SD Card Logger Capacity: > 2 GB (> 5-year capacity for 10-s averaging mode)
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, External USB Converter (Optional 4-20 mA Current; 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 Adapter; GPS (for 10-s data mode and above); Bluetooth; 4-20 mA Current Output; Cold-Weather Package (pump, lamp heater); High-Altitude Upgrade (pressure sensor); Extra-Long-Life, Low-Temperature Internal Air Pump; Low-Power Option; Rack-Mount Case Configuration

System Includes