The Health Benefits of Indoor Air Filtration Among Children

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

Detailed Description
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From April 2021 to November 2021, researchers conduct a randomized double-blind crossover trial on 110 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 system. Air purifiers are installed in the classroom and bedrooms of the children. Fresh air system are installed in the classroom. A total of 6 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.

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

Conditions
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Protective Effect of Air Purifier on Children's Health

Intervention / Treatment
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* Behavioral: Air Purifiers
* Behavioral: Sham Air Purifiers


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 8 ≤ 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

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 12 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Air purifier<br>Participants in this group receive an intervention of real air purifiers placed in the indoor environment. | Behavioral: Air Purifiers<br>* 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.<br>|
| Sham Comparator: Control<br>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<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of Forced Vital Capacity of Lung Function | The pulmonary function measures are performed by the professional medical staff. Before the pulmonary function test, subjects practice several times by themselves. During the examination, each subject stand and clamp the nose clip, and repeat the test, with the best result as the criterion. | Baseline and at the end of each 60 days intervention period | 
| Changes of FeNO | Use NIOX VERO Sensor to measure fractional exhaled nitric oxide (FeNO) as a biomarker for formaldehyde inhalation exposure. 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 FeCO | 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 Systolic Blood Pressure | Systolic blood pressure for each subject is conducted by the same trained staff using the same instrument. Average levels are calculated by the treatments of intervention or control. | Baseline and at the end of each 60 days intervention period | 
| Changes of LF/HF of HRV | Use Nihon Kohden Electrocardiograph to measure heart rate variability and examine the ratio between low frequency and high frequency (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 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of CRP | 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 | 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 PR | Examine persistent response (PR) as the index to test the focus ability of children. The test is performed by the Wsiconsin card sorting test through computer, and the index reflects the ability of cognitive transfer. The normal value is less than or equal to 27. | Baseline and at the end of each 60 days intervention period |