The Effect of Dyson Air Purifier in Improving Asthma Control
Condition: Asthma
MeSH terms: Asthma
Study type: Interventional

Summary: 
      To investigate the effect of reducing the level of allergens and pollutants in the bedroom
      and living room by placing a "Dyson air purifier", on poorly controlled asthmatic subjects.
    

Detailed description: 
      Asthma is one of the most common chronic diseases. Little change in morbidity and mortality
      has occurred despite improvements in pharmacotherapy. In the last few decades, there has been
      an increase in the prevalence of asthma and other allergic diseases. The precise cause for
      this increase in disease prevalence is not known but it has coincided with changes to the
      quality of indoor air with increases in the levels of allergens and pollutants. Bedroom
      exposure to dust-mite allergens has been linked to worsening asthma symptoms and increase in
      bronchial responsiveness. In places where dust mites cannot thrive, allergens from cat,
      cockroach and Alternaria assume importance. High indoor temperatures and humidity may, by a
      number of mechanisms, increase the allergenic burden, particularly the proliferation of
      house-dust mites and moulds. Therefore, modern living conditions are associated with a higher
      risk of allergen exposure causing increase in sensitisation and symptoms of asthma. In
      addition to allergens, the indoor environment contains other biological materials (such as
      microbiome and endotoxin), and pollutants (gases and particulate matter) which can adversely
      affect asthma development and morbidity. Indoor pollutants include smoke from cigarettes and
      wood, coal or gas fires, particulate materials associated with bio-fuel combustion, chemical
      vapours and gases including nitrogen dioxide (NO2), formaldehyde and volatile organic
      compounds (VOCs). The latter may come from sources including building products, cleaning
      agents, and paints. One such VOC is formaldehyde, which can be irritant to both upper and
      lower respiratory tract. Small particulate matter (PM2.5) is particularly damaging as it gets
      to the small airways of the lung. Major indoor sources of NO2 and particulate matter include
      gas stoves and cigarette smoke but outdoor sources such as traffic and industrial pollution
      can also contaminate indoor environment.

      It has also been suggested that exposure to pollutants can potentiate the effects of
      allergen. Indeed, a combination of high levels of indoor pollution and allergens is causally
      related to the development and severity of asthma. Allergens, microbiome and pollutants can
      interact with each other to augment the immune response leading to harmful effects on the
      airways.

      Thus, indoor air pollution is a significant environmental trigger for acute exacerbation of
      asthma (and other respiratory conditions such as COPD), leading to increasing symptoms,
      emergency department visits, hospital admissions and even mortality. An estimated 75% of
      hospital admissions for asthma are avoidable. Maintaining high air quality with lower levels
      of allergens and pollutants is therefore important in improving the health of individuals
      with asthma and other respiratory diseases. Therefore, a feasible and practical intervention
      that can reduce allergen and pollutant levels in the indoor air should reduce morbidity and
      improve asthma control.
    

Intervention name(s): Dyson Pure Cool - Active Purifier; Dyson Pure Cool - Placebo purifier
Intervention type(s): Device; Device
Intervention description(s): Free standing air purifier; Placebo air purifier
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment