Air Purifier Use and Respiratory Health in COPD Patients

Respiratory Benefits of Indoor Air Purification in Patients With Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

This randomized, double-blind, parallel-controlled trial aims to evaluate the effects of an indoor air purifier intervention on respiratory health in patients with Chronic Obstructive Pulmonary Disease (COPD).

Study Overview

• Status: Not yet recruiting
• Conditions: Respiratory Health
• Intervention / Treatment: Behavioral: Using air purifiers with high-efficiency particulate air (HEPA) and carbon filters; Behavioral: Using air purifiers with non-functional filtration system

Detailed Description

This randomized, double-blind, parallel-controlled trial will evaluate the effects of a 12-month home-based air purification intervention on respiratory health in non-smoking COPD patients in China. Participants will be randomized to receive an active or sham air purifier, with all participants and outcome assessors blinded to allocation. Health assessments, including clinical evaluation (e.g., pulmonary function tests, impulse oscillometry, and high-resolution computed tomography of the chest, etc.), questionnaire surveys (e.g., St. George's Respiratory Questionnaire and COPD Assessment Test, etc.), and biological sample collection (e.g., venous blood and urine, etc.), will be conducted at baseline and during follow-up visits at the 1st, 3rd, 6th, and 12th months. In addition, monthly telephone follow-ups will be performed to assess respiratory health status throughout the study.

• Study Type: Interventional
• Enrollment (Estimated): 120
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Haidong Kan, Ph.D; Phone Number: +86-021-54237908; Email: kanh@fudan.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age between 50 and 80 years old
• Physician diagnosis of COPD
• Living in Shanghai during the intervention period
• Subjects who have no plans to change homes during the intervention period
• Non-smokers and former smokers

Exclusion Criteria:

• Subjects living in a location other than home
• Subjects with a history of alcohol abuse
• Subjects with other chronic lung diseases, such as active tuberculosis, pulmonary fibrosis, cystic fibrosis, or alpha-1 antitrypsin deficiency
• Subjects with a history of thoracic surgery
• Subjects with a history of malignant tumors, such as lung cancer, liver cancer, or gastric cancer
• Subjects with diagnosed chronic hepatic or renal insufficiency, such as liver cirrhosis, chronic viral hepatitis, or autoimmune liver disease
• Subjects with acute myocardial infarction or unstable arrhythmia diagnosed within the past 6 weeks
• Subjects currently participating in other interventional studies

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active air purifier group; Participants in this group received a home-based air purifier equipped with high-efficiency particulate air (HEPA) and carbon filters.	Behavioral: Using air purifiers with high-efficiency particulate air (HEPA) and carbon filters; Participants in the intervention arm will receive active air purifiers, which will be installed in their bedroom and the room where they spend the most time at home. The devices will operate continuously for the entire intervention period.
Sham Comparator: Sham air purifier group; Participants in this group received an air purifier identical in appearance to those used by the active air purifier group, but without the filtration function.	Behavioral: Using air purifiers with non-functional filtration system; Participants in the intervention arm will receive sham air purifiers, which will be installed in their bedroom and the room where they spend the most time at home. The devices will operate continuously for the entire intervention period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in the percentage of low attenuation area at -950 Hounsfield units (%LAA-950)	%LAA-950 was defined as the percentage of voxels with attenuation lower than -950 Hounsfield units. A higher percentage reflects more severe emphysematous destruction of lung tissue.	Baseline and after the completion of the intervention period (12 months anticipated)
Changes of wall area percentage (WA%)	Airway wall thickness was calculated as the mean percentage of wall area (WA%) of prespecified segmental and subsegmental bronchi from each lung lobe.	Baseline and after the completion of the intervention period (12 months anticipated)
Changes of forced expiratory volume in 1 s (FEV1)	The pulmonary function measures are performed by a professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject is in a sitting position and clamps the nose clip, and repeats the test, with the best result as the criterion.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes of St. George's Respiratory Questionnaire (SGRQ) score	The SGRQ is a disease-specific instrument designed to measure impact on overall health, daily life, and perceived well-being in patients with obstructive airways disease. The total score is from 0 to 100. Higher scores indicate more limitations	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of COPD Assessment Test (CAT) score	The COPD Assessment Test (CAT) is a questionnaire for people with COPD. It is designed to measure the impact of COPD on a person's life and how this changes over time. The total score ranges from 0 to 40, with higher scores indicating a more severe impact of the disease on the patient's life.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
COPD exacerbations	Physician diagnosed exacerbation of acute COPD	Baseline and monthly thereafter through the 12th month

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change of Total Lung Volume (TLV)	Measured by quantitative CT (QCT) analysis software on inspiratory chest CT. Total lung volume is calculated by summing voxels segmented as lung parenchyma, reported in milliliters (mL).	Baseline and after the completion of the intervention period (12 months anticipated)
Change of mean pulmonary nodule size	The average diameter of identified pulmonary nodules is measured via chest CT and evaluated by a radiologist, reported in millimeters (mm).	Baseline and after the completion of the intervention period (12 months anticipated)
Change of mean airway wall thickness (WT)	Measured by quantitative CT (QCT) analysis software on inspiratory chest CT. The absolute thickness of the airway wall (mm) is measured from the inner to the outer lumen boundary.	Baseline and after the completion of the intervention period (12 months anticipated)
Change of mean luminal area (LA)	The luminal area (mm²) of the pre-specified segmental and sub-segmental bronchi will be measured using quantitative CT analysis software.	Baseline and after the completion of the intervention period (12 months anticipated)
Changes of forced expiratory volume in 1 s (FEV1) / forced vital capacity (FVC) ratio	The pulmonary function measures are performed by a professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject is in a sitting position and clamps the nose clip, and repeats the test, with the best result as the criterion.	Baseline, and at the 1st, 3rd, 6th,and 12th months (12 months anticipated)
Changes of forced vital capacity（FVC)	The pulmonary function measures are performed by a professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject is in a sitting position and clamps the nose clip, and repeats the test, with the best result as the criterion.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of maximal mid-expiratory flow (MMEF)	The pulmonary function measures are performed by a professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject is in a sitting position and clamps the nose clip, and repeats the test, with the best result as the criterion	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of maximal expiratory flow at 75% of forced vital capacity (MEF 75)	The pulmonary function measures are performed by a professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject is in a sitting position and clamps the nose clip, and repeats the test, with the best result as the criterion.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of maximal expiratory flow at 50% of forced vital capacity (MEF 50)	The pulmonary function measures are performed by a professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject is in a sitting position and clamps the nose clip, and repeats the test, with the best result as the criterion.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of maximal expiratory flow at 25% of forced vital capacity (MEF 25)	The pulmonary function measures are performed by a professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject is in a sitting position and clamps the nose clip, and repeats the test, with the best result as the criterion.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of the difference between respiratory resistance at 5 and 20 Hz (R5-R20)	The respiratory impedance measures are performed by a professional impulse oscillometry (IOS) device. During the examination, each subject is in a sitting position, wears a nose clip, and is instructed to maintain normal tidal breathing. Professional staff guide the subjects to support their cheeks with both hands to prevent upper airway shunting.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of airway resistance at 5 Hz (R5)	The respiratory impedance measures are performed by a professional impulse oscillometry (IOS) device. During the examination, each subject is in a sitting position, wears a nose clip, and is instructed to maintain normal tidal breathing. Professional staff guide the subjects to support their cheeks with both hands to prevent upper airway shunting.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of fractional exhaled nitric oxide (FeNO) levels	A NIOX VERO Sensor is used to measure fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation. After deep breathing, the subjects gently inhaled into the device. The instrument shows the subjects' FeNO levels.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of absolute eosinophil count	Detect the absolute count of eosinophils in peripheral blood samples to evaluate the potential response to air purification.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of absolute neutrophil count	Measure the concentration of neutrophils in blood samples to evaluate the potential response to air purification.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of plasma proteomic profile	Detect the concentration and expression levels of systemic proteins in blood samples to examine the differential protein signatures between the intervention and control groups.	Baseline and after the completion of the intervention period (12 months anticipated)
Changes of Apnea-Hypopnea Index (AHI)	AHI is a polysomnography-derived measure of sleep-disordered breathing severity, calculated as the total number of apnea and hypopnea events per hour of sleep. Higher AHI values indicate more severe sleep-disordered breathing.	Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)

Collaborators and Investigators

• Sponsor: Fudan University

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: March 20, 2026
• First Submitted That Met QC Criteria: March 26, 2026
• First Posted (Actual): April 1, 2026

Study Record Updates

• Last Update Posted (Actual): April 1, 2026
• Last Update Submitted That Met QC Criteria: March 26, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Randomized controlled trial; Chronic Obstructive Pulmonary Disease; Air purifier; Respiratory health
• Additional Relevant MeSH Terms: Pathologic Processes; Chronic Disease; Disease Attributes; Respiratory Tract Diseases; Lung Diseases; Lung Diseases, Obstructive; Pathological Conditions, Signs and Symptoms; Pulmonary Disease, Chronic Obstructive
• Other Study ID Numbers: FDUEH-11

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No