The Health Benefits of Indoor Air Filtration Among Children

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.

The forced vital capacity (FVC) is measured using spirometer (Model A1, BreathHome, China). FVC reflects the expiratory resistance of large airways.

The FEV1/FVC ratio is measured using smart spirometer (Model A1, BreathHome, China). FEV1/FVC ratio reflects the status of airway obstruction.

The peak expiratory flow (PEF) is measured using smart spirometer (Model A1, BreathHome, China). PEF reflects airway patency and respiratory muscle strength.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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).

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).

The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the QT correction for rate (QTc interval).

The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the amplitude of the R-wave in lead V5 (RV5).

The trained staff use a 12-lead electrocardiogram (ECG) monitor to measure the participants' the S-wave depth in lead V1 (SV1).

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).

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.

Detect the concentration of C-reactive protein in blood sample to examine the different level of inflammation between the group of intervention and control.

Detect the concentration of 8-hydroxydeoxyguanosine (8-OHdG) in urine sample as a marker of generalized, cellular oxidative stress to DNA.

Collect the exhaled breath condensate and identify the metabolites of exhaled breath condensate using Ultra-high performance liquid chromatography-tandem mass spectrometry.

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.

Orientation can be measured by the Attention Network Test and reflects an individual's selective attention to externally useful information.

Conflict can be measured by the Attention Network Test and reflects an individual's ability to process conflicting information.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

Collect peripheral venous blood, extract the serum, and identify the proteins of serum samples using 4D-label free technology.

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.

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.