A Survey of Calibration Techniques for Atmospheric Ozone Monitors.

摘要

A survey is presented of recent studies on calibration techniques for atmospheric ozone (O3) monitors. These calibration techniques are based on iodometry,ultraviolet photometry (UV) and gas phase titration (GPT). The iodometric procedures include the 1percent neutral buffered potassium iodide (NBKI) technique used by the Environmental Protection Agency (EPA), a 2percent NBKI method of the California Air Resources Board and a 1percent unbuffered KI technique previously used by the Los Angeles Air Pollution Control District (LAAPCD). The UV and GPT approaches are of rather recent application and brief descriptions of the calibration procedures are given. In summary the data show excellent agreement between O3determinations by UV or GPT and demonstrate that absolute measurements of trace O3concentrations can be made by either technique. On the other hand,the NBKI methods yield O3measurements 1to 13percent higher than absolute values when O3in dry air is analyzed. In the presence of humid air the NBKI measurements are high by factors ranging from 15to 30percent.