No abstract

The most direct implication is that results can be used as reference level for measurements in problem buildings and for individual measurements. The reference can also be used in research and the other results as basis for future hypotheses and for support of existing hypotheses.

In our first study in 1995, teachers, who had worked in a water-damaged school for more than 5 years, were tested for nasal histamine reactivity by rhinostereometry. They were found to have significantly increased reactivity compared with teachers in a school without these indoor-climate problems. This finding could not be explained by differences in atopy or other personal characteristics. In this 2-year follow-up study (1995-97), 26 of 28 teachers in the target school and all 18 teachers in the control school, who participated in the initial study, accepted to take part. They were tested with the same histamine provocation procedure and answered the same questionnaire as 2 years earlier. Technical measurements of temperature, relative humidity, dust, carbon dioxide, formaldehyde and total volatile organic compounds (TVOC) were carried out in both schools during the time period between the two test occasions. In this provocation test, the teachers from the repaired water-damaged school still demonstrated an increased reactivity to histamine compared with the teachers in the control school, but the difference between the growth curves of the provocation tests was less than in 1995. Teachers in the target school still complained about the indoor air quality more than their colleagues, although the complaints were less common. No major differences were observed in the technical investigation between the two schools and the measurements were all within values usually seen in schools in northern countries. Our conclusion is that the observed nasal mucosal hyperreactivity among the teachers in the renovated water-damaged school seems to persist over years and only slowly decrease even after successful remedial measures have been taken.

Upper airway symptoms have frequently been reported in people working or residing in damp buildings. However, little information has been available on objective pathophysiologic findings in relation to these environments. Twenty-eight teachers, who had worked for at least five years in a recently renovated school that had had severe moisture problems for years, were randomly selected for this study. Eighteen teachers, who had worked in another school that had no moisture problems, were randomly selected to serve as the control group. Although remedial measures had been taken, an increase in the prevalence of mucous membrane irritations was still reported by the teachers in the target school. We used a nasal challenge test with three concentrations of histamine (1, 2 and 4 mg/mL). Recordings of swelling of the nasal mucosa were made with rhinostereometry, a very accurate optical non-invasive method. The growth curves of mucosal swelling induced by the three concentrations of histamine differed significantly between the two groups (p < 0.01). The frequencies of atopy, evaluated with the skin-prick test, were almost identical in both groups. The study indicates that long-term exposure to indoor environments with moisture problems may contribute to mucosal hyperreactivity, of the upper airways. Such hyperreactivity also seems to persist for at least one year after remedial measures have been taken.

Eye goggles were used to estimate human thresholds for sensory eye irritation from four monoterpenes: (+)3-carene, (-)limonene and (+)alpha-pinene and (rac)alpha-terpineol all known as air pollutants emitted from wood. Only a ranking of the irritation thresholds relative to that of n-butanol is given. The measurements showed that the thresholds for eye irritation of the terpenes ranged from subthreshold to below 1,250 mg/m3. It appears that the irritation of 3-carene and limonene in contrast to the expectations was of the same size as or less than that of n-butanol. Too few subjects reported eye-irritation for alpha-pinene and alpha-terpineol to allow estimates of thresholds of these compounds which therefore have much less irritative potency than n-butanol, 3-carene, and limonene. The measurements of one terpene alcohol do not support the hypothesis that monoterpene alcohols, would have lower eye irritation threshold than monoterpene hydrocarbons. The sequence from strongest odorant to weakest was alpha-terpineol, 3-carene, n-butanol, limonene and alpha-pinene. In conclusion, the tested terpenes can probably be ruled out as cause of acute eye irritation indoors. The measured odor thresholds did not deviate from the few values reported in the literature.