The study is focussed on two main questions:

1. The importance of dampness of the building and home dust as a factor of the subjects= responses.
2. Can measures used in KLINIR predict the subjects' responses to the dust?

This study therefore was arranged to test the following hypotheses:

1. Does dust in general cause inflammatory/body perceptions through e.g. an irritation symptoms index.
2. Does the dust include effective odorants which affects an IAQ index?
3. Does dampness increase the content of organic or inorganic compounds e.g. of microbial origin that causes the dust to be more reactive? (Differences between the two types of dust)
4. Is the sensitivity of the subjects explaining the responses to exposures in a, b, or c? (Subject group and sensitivity index)

As explorative investigations biomarkers for exposures and sensitivity for practical usage are tested.

The study is focussed on two main questions:

c. The importance of dampness of the building and home dust as a factor of the subjects= responses.

d. Can measures used in KLINIR predict the subjects' responses to the dust?

As explorative investigations biomarkers for exposures and sensitivity are tested for practical use.

These investigations are made during experimental exposures of subjects to dust from dry and water damaged buildings. The responses of healthy KLINIR-sensitive subjects are predicted using personal sensitivity measures.

The design is a 3x3 Latin square design (cross-over design). The subjects will be their own controls and comparisons to placebo (clean air) were made. The study was double blinded and the subjects were only informed about details on design and exposures after the experiment and only if they asked.

This design eliminated effects of any learning or training during the investigations, and also the effects of season and weekday was eliminated. The subjects were exposed with 3-4 weeks interval to eliminate carry-over of effects from one exposure session to the next.

The design was replicated three times on three different groups of subjects each including 9 subjects. Each group of nine were divided into three groups of three subjects.

Inclusion Criteria:

• All in local area, nasal histamine responsive, grass allergic, from study KLINIR.

Exclusion Criteria:

• Pregnancy, house dust allergy, hyper-responding air ways, disease, disabled