Air Purifier Use and Respiratory Health in COPD Patients

June 5, 2026 updated by: Haidong Kan, Fudan University

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

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
120

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
      • Shanghai, China
        • Recruiting
        • School of Public Health, Fudan University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Changes in the percentage of low attenuation area at -950 Hounsfield units (%LAA-950)
Time Frame: Baseline and after the completion of the intervention period (12 months anticipated)
%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%)
Time Frame: Baseline and after the completion of the intervention period (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Changes of St. George's Respiratory Questionnaire (SGRQ) score
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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
Time Frame: Baseline and monthly thereafter through the 12th month
Physician diagnosed exacerbation of acute COPD
Baseline and monthly thereafter through the 12th month

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change of Total Lung Volume (TLV)
Time Frame: Baseline and after the completion of the intervention period (12 months anticipated)
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
Time Frame: Baseline and after the completion of the intervention period (12 months anticipated)
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)
Time Frame: Baseline and after the completion of the intervention period (12 months anticipated)
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)
Time Frame: Baseline and after the completion of the intervention period (12 months anticipated)
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
Time Frame: Baseline, and at the 1st, 3rd, 6th,and 12th months (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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
Time Frame: Baseline and after the completion of the intervention period (12 months anticipated)
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)
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
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)
Changes of blood lipids
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Measure the concentrations of total cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in blood samples to evaluate the potential metabolic response to air purification, particularly regarding cardiovascular risk.
Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of fasting plasma glucose
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Measure fasting plasma glucose levels in blood samples to assess the potential impact of air purification on acute glucose metabolism.
Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of skeletal muscle mass
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Measure skeletal muscle mass using bioelectrical impedance analysis to evaluate the potential effect of air purification on muscle preservation in COPD patients.
Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of body fat percentage
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Measure body fat percentage using bioelectrical impedance analysis to assess the potential impact of air purification on adiposity.
Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of sleep onset latency (SOL)
Time Frame: Baseline and daily thereafter through the 12th month
Measured nightly by a contactless ballistocardiography (BCG) sensor mat under the pillow to determine the time (minutes) from lights off to the first sleep epoch.
Baseline and daily thereafter through the 12th month
Changes of total sleep time (TST)
Time Frame: Baseline and daily thereafter through the 12th month.
Measured nightly by a contactless ballistocardiography (BCG) sensor mat under the pillow, summing all sleep epochs (minutes) from sleep onset to final awakening to assess the potential impact of air purification on sleep quantity.
Baseline and daily thereafter through the 12th month.
Changes of heart rate variability
Time Frame: Baseline and daily thereafter through the 12th month.
Calculated from inter-beat intervals (J-J intervals) extracted from BCG signals recorded by the under-pillow mat; reported as root mean square of successive differences (ms) to assess the potential impact of air purification on autonomic nervous system function.
Baseline and daily thereafter through the 12th month.
Major Adverse Cardiovascular Events (MACE)
Time Frame: Baseline and monthly thereafter through the 12th month
MACE is defined as a composite endpoint including: ischemic heart disease/coronary artery disease (I20, I24, I25), myocardial infarction (I21, I22, I23), atrial fibrillation (I48), venous thromboembolism (I74, I80, I82), heart failure (I50), and stroke (I60, I61, I62, I63, I64, I69). Events will be identified through medical records and follow-up assessments.
Baseline and monthly thereafter through the 12th month
Changes of handgrip strength
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Measure the maximum grip strength (in kilograms) using a hand dynamometer to evaluate the potential effect of air purification on muscle strength and functional status in COPD patients.
Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Changes of blood pressure
Time Frame: Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)
Measure systolic and diastolic blood pressure (in mmHg) using a validated electronic sphygmomanometer to evaluate the potential effect of air purification on hemodynamic function.
Baseline, and at the 1st, 3rd, 6th, and 12th months (12 months anticipated)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Fudan University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 30, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 20, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 26, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 1, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 9, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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

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