Controlled Human Exposure to Indoor Air, Dust and Ozone
Condition: Subjective Discomfort; General Mucosal Irritation; Acute Changes in Respiratory Outcomes; Acute Changes in Cardiovascular Outcomes; Changes in Biomarkers
Study type: Interventional

Summary: 
      The aim of the study is to provide information which may help to improve the quality of the
      life of persons exposed to indoor environments in Danish dwellings.

      The experiment will document if dust and ozone contribute to deterioration of indoor air
      quality and to the occurrence of symptoms and health effects.

      The study is aimed at testing the hypothesis that the presence of ozone potentiate the health
      and comfort effects of dust exposure in the indoor environment.

      Testing this hypothesis will be based on the following questions:

      Does house dust and ozone in concentrations frequently encountered in Danish dwellings cause
      unwanted health effects either by themselves or by interaction?

      If so, does the presence of ozone potentiate the expected irritative effects of dust?

      The challenge of these hypotheses will be made as a controlled experiment on humans in a
      climate chamber under controlled exposure conditions.

      This controlled human experiment should be able to substantiate the findings from the
      intervention studies.

      Furthermore, they ideally reflect something relevant to the general public and therefore
      should have maximum public appeal and application possibilities.
    

Detailed description: 
      This study is a part of a broader research programme established by CISBO ( Centre for Indoor
      air and Health in Dwellings). The purpose of the centre is to increase the general knowledge
      and to provide information on indoor air quality and related Health effects. The study may
      contribute with basic information on underlying pathophysiological mechanisms involved in
      human responses to these pollutants and in their interactive effects. The study includes as
      methods and techniques to detect minor changes in biomarkers suggesting early effect of
      exposure. These analyses will give information at a high sensitive level about the exposure
      effects on biomarkers for an array of symptoms and reactions.

      The study Group consitss of 24 non-smoking persons(aged 60-70). A controlled, randomized and
      balanced Latin square cross-over design using the participants as their own controls. The
      exposures are arranged in a full-scale climate chamber where the participants will be exposed
      for 5½ hour under controlled environmental conditions.

      The exposure facility (Climate chamber):

      The exposures are arranged at the controlled experimental facilities at our department which
      include climate chambers and exposure generators for dust and ozone. The exposure sessions
      will take place under controlled conditions in a 79 m3 climate chamber made of welded
      stainless steel optimized for experiments with gasses and particulate air pollutants. The
      chamber facility allows exposures with controlled ventilation, temperature and air humidity
      and has an efficient mixing of ventilation air with the chamber air.

      All participants will attend all four diff. exposure sessions:

      Dust (250-300µg/m3), Ozone (0,1ppm ozone),Dust+ozone (250-300µg/m3 + 0,1 ppm ozone), Filtered
      air (<20µg/m3). with at least 2 weeks between each exposure session to eliminate hang-over
      effects. The filtered air and dust and ozone contaminated sessions will be identical except
      for the air quality. The exposures are unknown to the participants and staff to keep the
      study double blinded. The blinding will be continued until the basic statistical analyses
      have been conducted.

      Selected subjective and objective health outcomes are measured at baseline and at follow-up
      at predefined time points.

      Health assessment and Measurements includes:

      Subjective symptoms, Respiratory outcomes (lung function, FENO, exhaled breath condensate,
      nasal lavages, Acoustic Rhinometri) Blood samples (inflammation biomarkers)
    

Intervention name(s): Dust; Ozone; Dust and Ozone; Placebo (Filtered air)
Intervention type(s): Device; Device; Device; Device
Intervention description(s): Dust (250-300µg/m3),; (0,1ppm ozone),; Active Dust (250-300 ug/m3)+Ozone(0,1ppm); Placebo treatment (Filtered air <20 ug/m3)
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Dust; Ozone; Indoor air quality; Indoor environment; Indoor climate; Cardiovascular diseases; Full body exposure; Exposure experiment with dust and ozone; Acute exposure to ozone and dust; Respiratory outcomes; Cardiovascular outcomes; Acoustic rhinometry; Body inflammatory markers; Cytokines; Exhaled FeNO; Nasal Lavage; Heart rate variability; Blood biomarkers; Subjective discomfort; General mucosal irritation