Health Benefits of Air Purifiers in Primary School Students

Health Benefits of Air Purifiers in Primary School Students: A Randomized Controlled Trial

This study aims to explore changes in cardiopulmonary function and other health indicators in primary school students with the intervention of air purifiers on a randomized controlled trial.

Study Overview

• Status: Active, not recruiting
• Conditions: Child; Cardiopulmonary Function
• Intervention / Treatment: Behavioral: Air purifier and fresh air ventilation systems with high-efficiency particulate air (HEPA) filters; Behavioral: Air purifier and fresh air ventilation systems without high-efficiency particulate air (HEPA) filters

Detailed Description

The investigators will conduct a randomized controlled trial among 110 healthy children in Jiaozuo city, Henan, China. The eligible children will be divided into two groups according to their classes and randomly receive interventions of either true or sham air purifiers. The air purifiers devices in classroom [air purifiers and fresh air ventilation systems] will operate during the school time and the devices in bedrooms (air purifiers) operate during the home time in the intervention period. All the participants and investigators will be blinded to the group assignment. Epidemiological questionnaires (i.e., basic characteristics, eating habits, daily schedule, etc.) will be conducted and health indicators (i.e., blood pressure, pulmonary function indicators, fractional exhaled nitric oxide, and fractional exhaled carbon monoxide) and biological specimens (i.e., morning urine, venous blood, exhaled breath condensate, and feces) will be evaluated and collected at baseline and after the completion of intervention period (4 months anticipated).

• Study Type: Interventional
• Enrollment (Estimated): 110
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Shanghai
    • Shanghai, Shanghai, China, 200032
      • Department of Environmental Health, School of Public Health, Fudan University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 8 years to 12 years (Child)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age of between 8 and 12 years old
• Males and female of ethnic Han
• Subjects who have no plans to change classroom during the intervention period
• Subjects who staying in Jiaozuo city during the intervention period

Exclusion Criteria:

• Subjects with asthma, childhood diabetes, childhood hypertension, and behavioral disorders
• Subjects who plan to transfer or move offsite within six months
• Subjects who decorated or plan to decorate home within six months
• Subjects with smokers in the household

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: True air purifier group; Children in this group will receive an intervention of air purifiers with high-efficiency particulate air (HEPA) filters.	Behavioral: Air purifier and fresh air ventilation systems with high-efficiency particulate air (HEPA) filters; This group will receive an intervention of true air purifiers. The air purifiers in classroom (air purifiers and fresh air ventilation systems with HEPA filters) will operate during the school time and the air purifiers in bedrooms (air purifiers with HEPA filters) operate during the home time in the intervention period (4 months anticipated).
Sham Comparator: Sham air purifier group; Children in this group will receive an intervention of air purifiers without high-efficiency particulate air (HEPA) filters.	Behavioral: Air purifier and fresh air ventilation systems without high-efficiency particulate air (HEPA) filters; This group will receive an intervention of sham air purifiers. The air purifiers in classroom (air purifiers and fresh air ventilation systems without HEPA filters) will operate during the school time and the air purifiers in bedrooms (air purifiers without HEPA filters) operate during the home time in the intervention period (4 months anticipated).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes of heart rate variability	Nihon Kohden Electrocardiograph and Carepatch Electrocardiogram are used to measure heart rate variability, including standard deviation of all normal-to-normal R-R intervals (SDNN), standard deviation of sequential five-minute R-R interval means (SDANN), root-mean-square difference of successive normal R-R intervals (RMSSD), low frequency (LF), and high frequency (HF) in intervention and control groups. To eliminate possible errors, measurements are conducted by the same trained staff using the same instrument.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of forced expiratory volume in 1 s (FEV1)	The pulmonary function measures are performed by the professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject in a sitting position and clamp the nose clip, and repeat the test, with the best result as the criterion.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of forced vital capacity (FVC)	The pulmonary function measures are performed by the professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject in a sitting position and clamp the nose clip, and repeat the test, with the best result as the criterion.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of forced expiratory volume in 1 s (FEV1) / forced vital capacity (FVC) ratio	The pulmonary function measures are performed by the professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject in a sitting position and clamp the nose clip, and repeat the test, with the best result as the criterion.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of peak expiratory flow (PEF)	The pulmonary function measures are performed by the professional medical device. Before the pulmonary function test, subjects practice several times with the guidance of professional staff. During the examination, each subject in a sitting position and clamp the nose clip, and repeat the test, with the best result as the criterion.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of fractional exhaled nitric oxide (FeNO) levels	A NIOX VERO Sensor is used to measure fractional exhaled nitric oxide (FeNO) as a biomarker for airway inflammation. After deep breathing, the subjects gently inhaled into the device. The instrument shows FeNO level of the subjects.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of fractional exhaled carbon monoxide (FeCO) levels	Use PICO to measure fractional exhaled carbon monoxide (FeCO) as a biomarker for cardiovascular risk. After deep breathing and holding the breath for 15 seconds, the subjects gently inhaled into the device. The instrument shows FeCO level of the subjects.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of blood pressure	Using Omron blood pressure monitor to measure the systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure for each subject by the trained staff using the same instrument.	Baseline and after the completion of intervention period (4 months anticipated)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes of C-reactive protein (CRP)	Detect the concentration of C-reactive protein (CRP) in blood sample to examine the different level of inflammation between the groups of intervention and control.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of 8-hydroxydeoxyguanosine (8-OHdG)	Detect the concentration of 8-hydroxydeoxyguanosine (8-OHdG) in urine sample of groups of intervention and control. 8-OHdG is a biomarker for DNA oxidative damage.	Baseline and after the completion of intervention period (4 months anticipated)
Changes of persistent response (PR)	Examine persistent response (PR) as the index to test the focus ability of children. The test is performed by the Wisconsin Card Sorting Test (WCST) through a computer, and the index reflects the ability of cognitive transfer. The normal value is less than or equal to 27.	Baseline and after the completion of intervention period (4 months anticipated)
Differences in metabolite levels detected in metabolomics between groups of intervention and control.	Mass spectrometry-based serum metabolomics is non-targeted. The study is to explore the differential metabolites in blood/urine/exhaled breath condensate (EBC) samples of the groups of intervention and control.	Baseline and after the completion of intervention period (4 months anticipated)

Collaborators and Investigators

• Sponsor: Fudan University

Study record dates

Study Major Dates

• Study Start (Actual): September 22, 2021
• Primary Completion (Actual): June 30, 2022
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: August 11, 2021
• First Submitted That Met QC Criteria: August 19, 2021
• First Posted (Actual): August 23, 2021

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 25, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: Air pollution; Particulate matter; Air Purifiers; Cardiopulmonary system
• Other Study ID Numbers: FDUEH-7

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
• product manufactured in and exported from the U.S.: No