Related Experiment Video
Updated: Sep 28, 2025
Bronchial Thermoplasty: A Novel Therapeutic Approach to Severe Asthma
Published on: November 4, 2010
HEPA filtration intervention in classrooms may improve some students' asthma
Stephen J Vesper1, Larry Wymer1, Brent A Coull2
1US Environmental Protection Agency, Center for Environmental Measurement and Modeling, Cincinnati, OH, USA.
Objective:
The School Inner-City Asthma Intervention Study 2 (SICAS 2) tested interventions to reduce exposures in classrooms of students with asthma. The objective of this post-hoc analysis was limited to evaluating the effect of high-efficiency particulate (HEPA) filtration interventions on mold levels as quantified using the Environmental Relative Moldiness Index (ERMI) and the possible improvement in the students' asthma, as quantified by spirometry testing.
Methods:
Pre-intervention dust samples were collected at the beginning of the school year from classrooms and corresponding homes of students with asthma (n = 150). Follow-up dust samples were collected in the classrooms at the end of the HEPA or Sham intervention. For each dust sample, ERMI values and the Group 1 and Group 2 mold levels (components of the ERMI metric) were quantified. In addition, each student's lung function was evaluated by spirometry testing, specifically the percentage predicted forced expiratory volume at 1 sec (FEV1%), before and at the end of the intervention.
Results:
For those students with a higher Group 1 mold level in their pre-intervention classroom than home (n = 94), the FEV1% results for those students was significantly (p < 0.05) inversely correlated with the Group 1 level in their classrooms. After the HEPA intervention, the average Group 1 and ERMI values were significantly lowered, and the average FEV1% test results significantly increased by an average of 4.22% for students in HEPA compared to Sham classrooms.
Conclusions:
HEPA intervention in classrooms reduced Group 1 and ERMI values, which corresponded to improvements in the students' FEV1% test results.
Insights
High-efficiency particulate (HEPA) air filtration in classrooms significantly reduced mold levels, leading to improved lung function (FEV1%) in students with asthma. This intervention offers a promising strategy for managing asthma in school environments.
Area of Science:
- Environmental Health
- Pediatric Allergy and Immunology
- Occupational Health
Background:
- Childhood asthma is a significant public health concern, often exacerbated by indoor environmental exposures in schools.
- Inner-city schools frequently present challenges related to air quality and allergen levels, impacting student health and attendance.
- Previous studies have indicated a link between indoor mold exposure and asthma exacerbations in children.
Purpose of the Study:
- To evaluate the impact of high-efficiency particulate (HEPA) air filtration on indoor mold levels in classrooms.
- To assess the effect of HEPA filtration on asthma-related outcomes in students, specifically lung function measured by spirometry.
- To determine the correlation between specific mold components (Group 1) and student respiratory health.
Main Methods:
- A post-hoc analysis of the School Inner-City Asthma Intervention Study 2 (SICAS 2) was conducted.
- Dust samples were collected pre- and post-intervention from classrooms and homes of 150 asthmatic students.
- Environmental Relative Moldiness Index (ERMI) and spirometry (FEV1%) were used to quantify mold exposure and lung function, respectively.
Main Results:
- A higher Group 1 mold level in classrooms compared to homes was inversely correlated with student FEV1% (p < 0.05).
- HEPA filtration significantly reduced average Group 1 and ERMI values in classrooms.
- Students in HEPA-filtered classrooms showed a significant average increase of 4.22% in FEV1% compared to those in sham-filtered classrooms.
Conclusions:
- Classroom-based HEPA filtration effectively reduces indoor mold burden, as indicated by lower ERMI and Group 1 mold levels.
- HEPA interventions in school settings can lead to measurable improvements in lung function for students with asthma.
- Targeting indoor air quality through filtration is a viable strategy for mitigating asthma symptoms in pediatric populations.
Related Concept Videos
01:25Antiasthma Drugs: Mast Cell Stabilizers and Anti-IgE Drugs
Mast cell stabilizers, such as cromolyn (also known as sodium cromoglycate) and nedocromil (Tilade), are effective drugs in asthma management. These stabilizers hinder histamine release by skillfully obstructing the activation of mast cells and other cellular entities. Notably, they navigate this task without...
01:29Asthma-I: Introduction
01:30Asthma-IV: Diagnostic and Management
Clinical Assessment for Asthma:
This is the first step in diagnosing and managing asthma. It includes:
01:26Asthma-II: Pathophysiology and Classification
Additionally, environmental and genetic factors play crucial roles in determining an individual's susceptibility to asthma and the severity of their condition.
Critical processes in asthma pathophysiology include:
01:30Asthma-IV: Nursing Management
First, in...
01:20Asthma: Pathogenesis and Management
Asthma is classified as allergic and non-allergic. Allergens such as dust mites, pollen, and pet dander trigger allergic asthma, while factors like cold air, intense emotions, or exercise can induce non-allergic asthma.