Investigation of different approaches to reduce allergens in asthmatic children's homes--the Breath of Fresh Air Project, Cornwall, United Kingdom.

During 2001 to 2004, a study was conducted to assess the indoor environmental and health impact of installing allergen-reducing interventions in the homes of asthmatic children. Based on the results of a pilot study, to determine an intervention that would provide improved symptom scores and a reduction in house dust mite allergen (Der p 1), mechanical ventilation and heat recovery (MVHR) systems were installed in 16 homes. Environmental and respiratory health assessments were conducted before and after the installation of the MVHR systems. The results indicated that the installation of MVHR systems reduced Der p 1 concentrations in living room carpets and mattresses. There were significant reductions in symptom scores for breathlessness during exercise, wheezing, and coughing during the day and night. Although, there was not a parallel control group for the main study, the lack of change in the pilot study control group (who did not receive an intervention), indicated that the changes in symptom scores were in part to do with the intervention. Larger scale trials are needed to determine the efficacy of MVHR systems in homes to improve indoor air quality and reduce asthma symptoms.