Assessing the Health Impact of Indoor Air Purification Using Health Data Obtained From Apple Watch Wearers

NCT07477834 | Completed

• 1 other identifier: HRPP-2024-148
• Study Type: interventional
• Target: 42
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to use the Apple Watch health metrics to assess short-term physiological responses in a randomized, double-blind, crossover real-world indoor purification intervention.

Conditions

Air Pollution Exposure; Heart Rate; Resting Heart Rate; HRV; SpO2; Respiratory Rate; Sleep

Keywords

Indoor Air Purification; Apple Watch; Digital Health Research

Outcome Measures

Primary Outcomes (6)

• Heart Rate Changes

  Instantaneous heart rate is measured by the Apple Watch in the background throughout the two interventions. Values are compared between the real and sham filtration to assess the effect of air purification. Unit: number of heartbeats per minute

  During each 2-week intervention (real and sham filtration); 1-week washout period is excluded

• Daily Resting Heart Rate Changes

  Resting heart rate is the daily average heart rate during rest measured by the Apple Watch in the background, reported by the Apple Watch as one single aggregated value per day, throughout the two interventions. Values are compared between the real and sham filtration to assess the effect of air purification. Unit: number of heartbeats per minute

  During each 2-week intervention (real and sham filtration); 1-week washout period is excluded

• Heart Rate Variability Changes

  Heart rate variability, variation in time between consecutive heartbeats, is measured by the Apple Watch in the background throughout the two interventions. The Apple Watch specifically measures the Standard Deviation of NN intervals (SDNN). Values are compared between the real and sham filtration to assess the effect of air purification. Unit: millisecond

  During each 2-week intervention (real and sham filtration); 1-week washout period is excluded

• Oxygen Saturation Changes

  Percentage of blood oxygen saturation is measured by the Apple Watch in the background throughout the two interventions. Values are compared between the real and sham filtration to assess the effect of air purification. Unit: %

  During each 2-week intervention (real and sham filtration); 1-week washout period is excluded

• Sleep Respiratory Rate Changes

  Respiratory rate is measured by the Apple Watch in the background during sleep throughout the two interventions. Values are compared between the real and sham filtration to assess the effect of air purification. Unit: number of breaths per minute

  During each 2-week intervention (real and sham filtration); 1-week washout period is excluded

• Sleep Stages Durations Changes

  Nightly duration of sleep stages (Core, Deep, REM, and Awake) is calculated by summing individual sleep samples and their respective timestamps as measured by the Apple Watch in the background during sleep throughout the interventions. Values are compared between the real and sham filtration to assess the effect of air purification. Unit: hour

  During each 2-week intervention (real and sham filtration); 1-week washout period is excluded

Study Arms (2)

Real filtration first, followed by sham filtration

EXPERIMENTAL

Participants were randomly assigned to begin with either the real filter or sham filter, before switching halfway into the study. This group first received real air filtration for 2 weeks, followed by a 1-week washout period, and then 2 weeks of sham filtration.

Behavioral: Real Filtration; Behavioral: Sham Filtration

Sham filtration first, followed by active filtration

PLACEBO COMPARATOR

Participants were randomly assigned to begin with either the real filter or sham filter, before switching halfway into the study. This group first received sham filtration for 2 weeks, followed by a 1-week washout period, and then 2 weeks of real filtration.

Behavioral: Real Filtration; Behavioral: Sham Filtration

Interventions

Real Filtration BEHAVIORAL

IQAir Atem X purifier with real filter (HyperHEPA) which is designed to remove PM2.5

Real filtration first, followed by sham filtration; Sham filtration first, followed by active filtration

Sham Filtration BEHAVIORAL

IQAir Atem X purifier with sham filter which does not filter any PM2.5. When installed inside the purifiers, the sham filter produced the same appearance and sound as the real one, making the two interventions indistinguishable to participants.

Real filtration first, followed by sham filtration; Sham filtration first, followed by active filtration

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Own an Apple Watch Series 6 or above
• Own an iPhone
• iPhone and Apple Watch updated to the latest software versions (iOS 18 and watchOS 11, as of January 2025) to ensure consistent and latest algorithms for measuring health
• Age range: 18 - 40
• Non-smoker, defined as never smoke in life or have stopped smoking for at least one year before the start of the study

You may not qualify if:

• Own a Apple Watch sold by Apple in the United States on or after January 18, 2024 which does not support SpO2 measurements. These are indicated with part numbers ending in LW/A.
• Own or currently use an air quality monitor that can measure particulate matter
• Own or currently use an air purifier (humidifier or scent diffuser is fine)
• Any known pre-existing conditions: asthma, diabetes, obesity (BMI \> 30), or chronic cardiorespiratory disease
• Taking any medications that might affect the heart and lung function

Sponsors & Collaborators

• New York University Abu Dhabi: lead
• IQAir AG: collaborator
• LUT University: collaborator

Study Sites (1)

New York University Abu Dhabi

Abu Dhabi, United Arab Emirates

Location

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: March 12, 2026
• First Posted: March 17, 2026
• Study Start: February 9, 2025
• Primary Completion: June 22, 2025
• Study Completion: June 22, 2025
• Last Updated: March 17, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

AE (1)