Development of the Formaldehyde Automatic Analyzer and Test to Evaluate Its Performanace

In Japan, the guideline value for the concentration of indoor formaldehyde was set up in 1997. It was 0.08 ppm as the 30-minute average value, which was the same as the guideline value of WHO. At the same time, the sampling method in a newly built or renovated house was also described in the guideline. However, there have been only a few cases in which the concentration change of indoor formaldehyde was actually measured. This time, an analyzer capable of continuously measuring 30-minute average values was developed. It is based on the acetylacetone absorption spectrophotometric method. It can measure a concentration range of 0 0.2 ppm. It was confirmed that the analyzer was not affected by nitrogen dioxide, sulfur dioxide, ozone and aldehydes other than formaldehyde. INDEX TERMS Formaldehyde, Continuous Analyzer, Acetylacetone absorption spectrophotometric method INTRODUCTION Formaldehyde (HCHO), is a chemical substance that has been drawing attention along with volatile organic compounds (VOCs) recently as a substance which causes sick building syndrome (SBS) or chemical sensitivity (CS) in humans. In Japan, an indoor formaldehyde concentration of 0.08 ppm (0.1 mg/m) (30-minute average value) was set up as the guideline value in 1997. In addition, the guideline for the sampling method dictates that in the case of a newly built or renovated house its windows are to be opened for 30 minutes first, and then closed for more than five hours before sampling. Though the guideline value and the sampling method were given, there have been only a few reports indicating how the concentration of HCHO changes in an actual room. We have been manufacturing automated analyzers capable of continuously analyzing HCHO in atmosphere at one-hour increments (in compliance with the AHMT method). However, these analyzers tend to be complicated and bulky in size due to many reasons such as using chemicals, which made them unsuitable for home use. Other machines based on the Para Rosaniline method, MBTH method, electrochemical method, etc. have been reported. However, there are hardly any reports on continuously analyzed data. For this reason, a compact measuring instrument was built utilizing the acetylacetone absorption spectrophotometric method that is generally used for continuous measurement in this research field. That is, an automatic measuring instrument capable of continuously measuring the indoor concentration of HCHO at levels near the guideline value was developed and various characteristics of the instrument were tested. The following are the findings that have been obtained so far. 1 Contact Author email: [email protected] Proceedings: Indoor Air 2002