Accuracy and practicality of a portable ozone monitor for personal exposure estimates

Abstract

Accurate measurements of personal exposure to atmospheric pollutants such as ozone are important for understanding health risks. We tested a new personal ozone monitor (POM; 2B Technologies) for accuracy, precision, and ease of use. The POM's measurements were compared to simultaneous ozone measurements from a 2B Model 205 monitor and a ThermoScientific 49i monitor, and multiple POMs were placed side-by-side to check precision. Tests were undertaken in a controlled environmental facility, outdoors, and in a private residence. Additionally, ten volunteers wore a POM for five days and answered a questionnaire about its ease of use. The POM measured ozone accurately compared to the 49i ozone monitor, with average relative differences of less than 8%. In the controlled environment tests, the POM's ozone measurements did not change in the presence of additional atmospheric constituents with similar absorption lines to ozone, though there may have been a small decrease in precision and accuracy. Precision between POMs varied by environment (r² = 0.98 outdoors; r² = 0.3 to 0.9 in controlled lab conditions). Volunteers reported that the POM was reasonably comfortable to wear, although all reported that they felt that it was too noisy. Overall, the POM is a viable option for personal ozone monitoring.

Figure 1

One-minute average ozone measurements from POM 1 (x-axis) and POM 2 (y-axis) while ozone was generated in the CEF.

Figure 2

Correlation of 5-minute average ozone concentrations from two POMs during 24-hour outdoor testing period with line of best fit.

Figure 3

One-minute average ozone concentrations [ppb] from POM 1 (x-axis) and POM 2 (y-axis) when both were worn indoors by a volunteer. During the third period, the volunteer cooked stir-fry.

Figure 4

One-minute average ozone measurements [ppb] in CEF. See text for explanation of adjusted POM values.

Figure 5

One-minute average ozone measurements [ppb] in CEF with TEX mixture present. See text for explanation of adjusted POM 2 values.

Figure 6

One-minute average ozone measurements [ppb] in CEF with aldehydes present. See text for explanation of adjusted POM 2 values.

Figure 7

One-minute average ozone concentration in the CEF with vanillin and anisole present.

Figure 8

One-minute average outdoor ozone measurements from 205 instrument (x-axis) and POM (y-axis).

Figure 9

One-minute average ozone concentrations during in-home testing. For the plotted points, the POM 2 was placed directly on top of the 205 monitor.