#03-139

Complete

Date Full Report Received

06/30/2004

Date Abstract Report Received

07/26/2006

Investigation

Institution:
Primary Investigator:

Single Point Monitor is a portable, relatively low cost instrument that can detect relatively low levels of gaseous ammonia and hydrogen sulfide. It is an approved method for measurement of ambient hydrogen sulfide levels by the Minnesota Pollution Control Agency. This project quantified SPM performance based on a side-by-side comparison with sophisticated, accurate analyzers. The SPM reading is affected by moisture content in the sampling air. In a typical field condition of swine facility with ambient hydrogen sulfide range from 0 to 90 parts per billion (ppb), SPMs tend to record lower concentration (70 – 101% of the “true” values). Hence concurrent knowledge of moisture content in the sample air is necessary to compensate for the moisture interference. The moisture interference on SPM measurement can be mathematically compensated quite well for hydrogen sulfide gas by laboratory-derived equations, achieving 90% agreement with the reference value. In comparison, such compensation was not as effective for ammonia measurement.