The Health Benefits of Indoor Air Filtration Among Children

September 21, 2024 updated by: Tiantian Li

Investigating the Health Benefits of Indoor Air Filtration Among Children: a Randomized Crossover Trial in Jiaozuo, China

This study aims to explore the health benefits of air purifier on the impact of air pollutants on children's health.

Study Overview

Status

Status

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

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

From April 2021 to December 2021, researchers conduct a randomized double-blind crossover trial on about 100 healthy children in Jiaozuo City, Henan Province. The children are divided into two groups according to their classes and alternated the use of true or sham purifiers devices, including air purifiers and fresh air ventilation. Air purifiers are installed in the classroom and bedrooms of the children. Fresh air ventilation is installed in the classroom. A total of 4 epidemiological surveys are conducted on the subjects, with an interval of 60 days or more. All participants and research staffs were blinded to the group assignment. In addition, air pollutant exposure monitoring, questionnaire surveys, physical examinations, and biological sample collection are conducted on the research subjects each time. The biological samples are further tested for the concentration levels of related biomarkers such as the respiratory system, cardiovascular system, metabolic system, and nervous system. Furthermore, comprehensive evaluation of children's behavioral ability is also carried out. Ambient PM2.5 and indoor PM2.5 exposure concentrations are monitored in 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 (Actual)

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.
105

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
      • Beijing, China, 100021
        • National Institute of Environmental Health, Chinese Center for Disease Control and Prevention

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

8 years to 12 years (Child)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 10 ≤ 12 years old
  • Volunteer to participate in this study

Exclusion Criteria:

  • Current and past medical history, including asthma, childhood diabetes, childhood hypertension, behavior-related diseases
  • Students who plan to transfer or move within six months
  • Unable to cooperate with follow-up

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: Crossover 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: Air purifier
Participants in this group receive an intervention of real air purifiers placed in the indoor environment.
Behavioral: Air Purifiers
Students are divided into two groups: intervention group and control group. The intervention team places an air purifier in the indoor environment to intervene. All the indoor environment of the group use the same qualified air purifier, and all participants and research staffs are blinded to the group assignment.
Sham Comparator: Control
Participants in this group receive an intervention of sham air purifiers, we just remove the filter in the purifiers, and the other treatments are the same as the real purification group.
Behavioral: Sham Air Purifiers
The control group is also intervened. The intervention is to place a sham air purifier (remove the filter screen) in the indoor environment, and all the indoor environment use the same air purifier as the intervention group. All participants and research staffs are blinded to the group assignment.

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 of FeCO
Time Frame: Baseline and at the end of each 60 days intervention period
Use Pico Smokerlyzer to measure fractional exhaled carbon monoxide (FeCO). After deep breathing, the subjects held their breath for 15 seconds and then gently inhaled into the device. The instrument showed FeCO level and the estimated value of carboxyhemoglobin in blood.
Baseline and at the end of each 60 days intervention period
Changes of FEV1
Time Frame: Baseline and at the end of each 60 days intervention period
The forced expiratory volume in 1 s (FEV1) is measured using a smart spirometer (Model A1, BreathHome, China) supervised by professional medical staff. Before the pulmonary function test, subjects will practice several times by themselves. During the examination, each subject stands and clamps the nose clip, and repeats the test, with the best result as the criterion. FEV1 reflect pulmonary function.
Baseline and at the end of each 60 days intervention period
Changes of FVC
Time Frame: Baseline and at the end of each 60 days intervention period
The forced vital capacity (FVC) is measured using spirometer (Model A1, BreathHome, China). FVC reflects the expiratory resistance of large airways.
Baseline and at the end of each 60 days intervention period
Changes of FEV1/FVC ratio
Time Frame: Baseline and at the end of each 60 days intervention period
The FEV1/FVC ratio is measured using smart spirometer (Model A1, BreathHome, China). FEV1/FVC ratio reflects the status of airway obstruction.
Baseline and at the end of each 60 days intervention period
Changes of PEF
Time Frame: Baseline and at the end of each 60 days intervention period
The peak expiratory flow (PEF) is measured using smart spirometer (Model A1, BreathHome, China). PEF reflects airway patency and respiratory muscle strength.
Baseline and at the end of each 60 days intervention period
Changes of FEF25-75%
Time Frame: Baseline and at the end of each 60 days intervention period
The forced expiratory flow at 25-75% of FVC (FEF25-75%) is measured using smart spirometer (Model A1, BreathHome, China). FEF25-75% reflects the small airway obstruction.
Baseline and at the end of each 60 days intervention period
Changes of MEF75%
Time Frame: Baseline and at the end of each 60 days intervention period
The maximal expiratory flow at 75% of FVC (MEF75%) is measured using smart spirometer (Model A1, BreathHome, China). MEF75% reflects the terminal stage of expiratory flow rate.
Baseline and at the end of each 60 days intervention period
Changes of MEF50%
Time Frame: Baseline and at the end of each 60 days intervention period
The maximal expiratory flow at 50% of FVC (MEF50%) is measured using smart spirometer (Model A1, BreathHome, China). MEF50% reflects the interim stage of expiratory flow rate.
Baseline and at the end of each 60 days intervention period
Changes of MEF25%
Time Frame: Baseline and at the end of each 60 days intervention period
The maximal expiratory flow at 25% of FVC (MEF25%) is measured using smart spirometer (Model A1, BreathHome, China). MEF25% reflects the early stage of expiratory flow rate.
Baseline and at the end of each 60 days intervention period
Changes of FeNO
Time Frame: Baseline and at the end of each 60 days intervention period
Use NIOX VERO Sensor to measure fractional exhaled nitric oxide (FeNO) as a biomarker for airway inflammation level. After deep breathing, the subjects gently inhaled into the device. The instrument showed FeNO level of the subjects.
Baseline and at the end of each 60 days intervention period
Changes of Blood Pressure
Time Frame: Baseline and at the end of each 60 days intervention period
The professional staffs wrap the BP cuff around the left upper arm of children to measure BP using the Omron electronic sphygmomanometers (OMROM, J751). BP is measured at 2-minute intervals, with a total of three measurements taken. If the difference of BP values between the last two measurements exceeds 5 mmHg, additional measurements are performed. Each child is allowed to measure BP at least three times and up to five times. The BP indicators includes SBP, DBP, MAP and PP.
Baseline and at the end of each 60 days intervention period
Changes of heart rate variability
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staffs conduct a 3-minute comprehensive assessment using the handheld electrocardiographic recorder-CarePatch (ECG-H01, Hangzhou Proton Technology Co., Ltd., China) to measured HRV. The time-domain indicators include standard deviation of all normal-to-normal intervals (SDNN), the root mean square of successive differences between adjacent normal cycles (rMSSD), the percentage of adjacent NN interval differences greater than 50 ms (pNN50); and the frequency-domain indicators include very low frequency (VLF), low frequency (LF), high frequency (HF), the ratio of LF to HF (LF/HF). To eliminate possible error, subjects are conducted by the same trained staff using the same instrument.
Baseline and at the end of each 60 days intervention period
Changes of PR interval
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the interval of the beginning of the P wave to the beginning of the QRS complex (PR interval).
Baseline and at the end of each 60 days intervention period
Changes of QRS duration
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the interval of the beginning of Q wave to the end of the S wave (QRS duration).
Baseline and at the end of each 60 days intervention period
Changes of QT interval
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the interval from the onset of the QRS complex to the end of the T wave (QT interval).
Baseline and at the end of each 60 days intervention period
Changes of QTc interval
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the QT correction for rate (QTc interval).
Baseline and at the end of each 60 days intervention period
Changes of RV5
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the amplitude of the R-wave in lead V5 (RV5).
Baseline and at the end of each 60 days intervention period
Changes of SV1
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the S-wave depth in lead V1 (SV1).
Baseline and at the end of each 60 days intervention period
Changes of RV5+SV1
Time Frame: Baseline and at the end of each 60 days intervention period
The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the sum of the R-wave amplitude in lead V5 and the S-wave amplitude in lead V1(RV5+SV1).
Baseline and at the end of each 60 days intervention period
Changes of academic performance
Time Frame: Baseline and at the end of each 60 days intervention period
The assessment of academic performance consists of standardised scores (maths, chinese and total) and the relative rank of the scores within grade. Standardised scores are converted from raw scores (with minimum value of 0 and maximum of 100) according to the number of exams and classes, indicating the position of the sample value in the normal distribution curve, with higher value showing better outcome. Rankings are converted from place rankings of raw values, with lower value showing better outcome.
Baseline and at the end of each 60 days intervention period

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 CRP
Time Frame: Baseline and at the end of each 60 days intervention period
Detect the concentration of C-reactive protein in blood sample to examine the different level of inflammation between the group of intervention and control.
Baseline and at the end of each 60 days intervention period
Changes of 8-OHdG
Time Frame: Baseline and at the end of each 60 days intervention period
Detect the concentration of 8-hydroxydeoxyguanosine (8-OHdG) in urine sample as a marker of generalized, cellular oxidative stress to DNA.
Baseline and at the end of each 60 days intervention period
Changes of metabolites in exhaled breath condensate
Time Frame: Baseline and at the end of each 60 days intervention period
Collect the exhaled breath condensate and identify the metabolites of exhaled breath condensate using Ultra-high performance liquid chromatography-tandem mass spectrometry.
Baseline and at the end of each 60 days intervention period
Changes of the role of alertness
Time Frame: Baseline and at the end of each 60 days intervention period
Alertness can be measured by the Attention Network Test and reflects an individual's acquisition and maintenance of a state of alertness to a particular type of information or target.
Baseline and at the end of each 60 days intervention period
Changes of the role of orientation
Time Frame: Baseline and at the end of each 60 days intervention period
Orientation can be measured by the Attention Network Test and reflects an individual's selective attention to externally useful information.
Baseline and at the end of each 60 days intervention period
Changes of the role of conflict
Time Frame: Baseline and at the end of each 60 days intervention period
Conflict can be measured by the Attention Network Test and reflects an individual's ability to process conflicting information.
Baseline and at the end of each 60 days intervention period
Changes of Wisconsin Card Sorting Test indicators
Time Frame: Baseline and at the end of each 60 days intervention period
WCST contains absolute indicators of cognitive executive functioning which include level of conceptualisation, persistence and set maintenance. The cognitive absolute indicators include conceptual thinking includes complete correct (TC), complete error (TE), non-persistent error (NPE), conceptual level response (CLR) and category completed (CC), persistence includes persistent response (PR) and persistent error (PE), and pooling maintenance includes inability to maintain pooling (FM).WCST percentage metrics are similar in meaning to the absolute metrics, and can be categorised into the level of conceptualisation and the Two dimensions of persistence. Cognitive percentage indicators include conceptual thinking consists of total correct percentage (%TC), total error percentage (%TE), non-persistent error percentage (%NPE), and conceptual level response percentage (%NPE); persistence consists of persistent response percentage (%PR) and persistent error percentage (%PE).
Baseline and at the end of each 60 days intervention period
Changes of the position total number
Time Frame: Baseline and at the end of each 60 days intervention period
The position total number is the number of all position-related stimuli during the N-back test. The subjects need to remember how each position changed and judge whether a duplicate position stimulus appeared after N rounds.
Baseline and at the end of each 60 days intervention period
Changes of the position number correct
Time Frame: Baseline and at the end of each 60 days intervention period
The position number correct is the number of times during the N-back test that the subjects were able to correctly judge whether or not a repeated position appeared in N rounds. A higher number correct indicates that the tester performed better in remembering and recognising the location.
Baseline and at the end of each 60 days intervention period
Changes of the position percentage correct
Time Frame: Baseline and at the end of each 60 days intervention period
Changes of position percentage correct is the accuracy of the -N-back test subjects in position-related tasks, expressed as a percentage. It is calculated as (number of locations correct ÷ total number of location stimuli) × 100%. A high rate of correctness indicates that the subjects' accuracy in location memory is high.
Baseline and at the end of each 60 days intervention period
Changes of the color total number
Time Frame: Baseline and at the end of each 60 days intervention period
The color total number is the number of all colour-related stimuli during the -N-back test. The subjects were required to remember the colour changes and determine whether a repeated colour stimulus has occurred after N-backs.
Baseline and at the end of each 60 days intervention period
Changes of the color number correct
Time Frame: Baseline and at the end of each 60 days intervention period
The color number correct is the number of times during the N-back test that the subjects were able to correctly judge whether a repeated colour appeared or not in N rounds. A higher correct count indicates that the tester performed better in colour memory and recognition.
Baseline and at the end of each 60 days intervention period
Changes of the color percentage correct
Time Frame: Baseline and at the end of each 60 days intervention period
Changes of color percentage correct is is the subjects' accuracy in colour-related tasks during the N-back test, expressed as a percentage. It is calculated as (number of colours correct ÷ total number of colour stimuli) × 100%. A high rate of correctness indicates that the subjects' accuracy in colour memory is high.
Baseline and at the end of each 60 days intervention period
Changes of the shape total number
Time Frame: Baseline and at the end of each 60 days intervention period
The shape total number is the number of all shape stimuli during the N-back test. The subjects need to remember the shape changes and judge whether a repeated shape stimulus has appeared after the N-back.
Baseline and at the end of each 60 days intervention period
Changes of the shape number correct
Time Frame: Baseline and at the end of each 60 days intervention period
The shape number correct is the number of times during the N-back test that the subjects were able to correctly judge whether or not a repeated shape appeared in N rounds. A higher number correct indicates that the subjects performed better in shape memory and recognition.
Baseline and at the end of each 60 days intervention period
Changes of the shape percentage correct
Time Frame: Baseline and at the end of each 60 days intervention period
Changes of shape percentage correct is the subjects' accuracy in shape-related tasks during the N-back test, expressed as a percentage. It is calculated as (number of shapes correct ÷ total number of shape stimuli) × 100%. A high rate of correctness indicates that the subjects' accuracy in shape memory is high.
Baseline and at the end of each 60 days intervention period
Changes of proteins in serum
Time Frame: Baseline and at the end of each 60 days intervention period
Collect peripheral venous blood, extract the serum, and identify the proteins of serum samples using 4D-label free technology.
Baseline and at the end of each 60 days intervention period
Changes in biomarkers identified from other omics
Time Frame: Through study completion, up to 10 years
Collect peripheral venous blood, exhaled breath condensate, urine, saliva, oral cells, oral swabs, nasal swabs, skin swabs, nails and feces samples, then identify the biomarkers by conducting transcriptomic, microbiome analyses, etc.
Through study completion, up to 10 years
Changes in other targeted biomarkers of interest
Time Frame: Through study completion, up to 10 years
Collect peripheral venous blood, exhaled breath condensate, urine, saliva, oral cells, oral swabs, nasal swabs, skin swabs, nails and feces samples, then identify the other targeted biomarkers of interest.
Through study completion, up to 10 years

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.
Tiantian Li

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Tiantian Li, National Institute of Environmental Health, Chinese Center for Disease Control and Prevention

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.
April 10, 2021

Primary Completion (Actual)

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 15, 2021

Study Completion (Actual)

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.
May 15, 2022

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 30, 2021

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.
April 6, 2021

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 8, 2021

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.
September 24, 2024

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.
September 21, 2024

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.
September 1, 2024

More Information

Terms related to this study

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.
  • 202032

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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