Monitoring badges are integrating rather than real-time devices, yielding an accumulated value—often incorrectly interpreted as an “average”—calculated over the time period the badge was active. The advantage of real time monitoring is that it WILL keep track of spikes and excursions, while a badge will merely accumulate this information into the total.
Since OSHA does define an Excursion Limit of 5 ppm, as averaged over a sampling period of 15 minutes [29 CFR 1910.1047 (c)(2)], and badges cannot possibly elucidate this, one must question their utility!
One other problem with badges is that badge data can be easily sabotaged by simply inserting the badge in a high EtO area for a period of time. To duplicate such malicious activity with a real time monitor would require that a sampling point be exposed to an artificially induced high concentration of EtO. Not only would this be hazardous to the perpetrator, but it would be readily exposed as false information.
Still, if you wish to compare badge data with real-time monitoring data, you should do the following:
(These points assume that an EtO monitoring system is installed, along with data acquisition)
a) Make sure that your Arc-Max® shift settings correspond to the time(s) of day that badge data is being taken.
b) With the use of MS-Excel, or simply by inspection and arithmetic, take your 8-hour average data on Arc-Max® and create an average over as many days as the badge was operative.
c) If the Arc-Max® data is higher, it is probably because the badge response is integrated and is much slower than the instrument. Some peaks and excursions, if of short enough duration, may not be detected. Also, since the badge chemistry MAY be more specific to EtO than the instrument, carbon monoxide or isopropyl alcohol interferences could have increased the Arc-Max® data.
d) If the Arc-Max® data is lower, suspect badge misuse, either in that personnel are going into areas not monitored by the instrument, or simple sabotage.