area. It was then placed into wash bottles (0.25-L), and air was passed through them at the rate of 0.1 L/min. Charcoal (for solvent analysis) or Amberlite XAD (coated with 2,4-dinitrophenyl hydrazine for aldehyde analyses) was used to collect the emissions for 30 to 60 min. Solvent concentrations were measured using gas chromatography (GC), and aldehyde analyses were performed with liquid chromatography. The relative solvent emissions calculated were based on measurement times, surface area, and amounts of solvent/aldehyde released. Mann-Whitney's rank sum test was used for testing the statistical significance of paired t-values. Norback [l983b] found small but measurable amounts of formaldehyde (0.1 to 0.3 mg/m3; detection level=0.3 mg/kg per hr) in 3 of 4 fresh CCP samples. No glutaraldehyde was detected (detection level=0.l mg/kg per hr). No aldehyde emissions were detected from any of the papers that were 1 to 2 years old. One week after the microcapsules had been crushed, four of the five solvents studied were still being released in measurable quantities, including monoisopropyl biphenyl (MIPB), kerosene, phenylxylylethane, and diisopropylbiphenyl—but not hydrogenated terphenyl. The kerosene emissions ranged from 5 to 60 mg/m3, with the two CCP samples not linked to work-related respiratory tract symptoms yielding the lowest kerosene emissions. On the basis of this observation, the author tested three different groups of kerosene-containing CCP, some of which had observed links with work-related respiratory tract symptoms. He demonstrated in this study that no links existed between mucous membrane symptoms and kerosene emissions. He also showed that there were no statistically demonstrable trends toward a link between work-related respiratory tract symptoms and high kerosene emissions—even where all CCPs associated with respiratory symptoms were combined, and regardless of the solvent content. This difference was attributed to the difference in encapsulation processes (MIPB used "poly- mer," and hydrogenated terphenyl used gelatin). The author noted that the kerosene concentrations in the wash bottles were 10 to 100 times higher than those measured in the breathing zones of workers involved in intensive manual handling of CCP. The author also concluded that aldehyde emissions from CCP were not likely to explain the irritative mucous membrane symptoms among workers who handle such paper. Table 3-2 demonstrates how writing on CCP (and thereby crushing the microcapsules) affects the solvent emissions from the paper.
Norbäck and Göthe 1983. In a Swedish study, Norback and Gothe [1983] collected personal and area samples in Stockholm at ll offices where large quantities of CCP were handled and at five printing shops where form (manifold) sets of CCP were produced. The measurements were made from January 1980 to November 1981, mainly during the winter half of the year (the period in which problems
| CCP form treatment | Kerosene emissions | MIPB emissions |
|---|---|---|
| Unused | 0.35 | 0.33 |
| Crushed (fresh writing) | 15.5 | 0.54 |
| Week—old writing | 3.7 | 0.24 |
Source: Norbäck [1983b].
