Air Filtration for Heart Disease

(SAPIA Trial)

Overseen By Junfeng Zhang, PhD

Age: 65+

Sex: Any

Trial Phase: Academic

Sponsor: University of Southern California

Disqualifiers: Dementia, Alzheimer's, Active cancer, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 6

112 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests whether using a HEPA air filter (High-Efficiency Particulate Air filter) at home can slow the progression of heart disease in individuals with a history of ischemic heart disease. The study will compare two groups: one using real HEPA filters and another using a placebo filter to determine any differences. Individuals with stable ischemic heart disease living in Los Angeles County may qualify for this trial. As an unphased study, this trial offers a unique opportunity to contribute to research that could enhance heart health for many.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It is best to discuss this with the trial coordinators or your doctor.

What prior data suggests that HEPA filtration is safe for adults with ischemic heart disease?

Research shows that HEPA air filters are generally safe for home use. Studies have found that these filters effectively reduce indoor air pollution, particularly tiny particles known as PM2.5, which can harm heart health. One study discovered that using HEPA filters at home led to a noticeable decrease in systolic blood pressure (the top number in a blood pressure reading) for people with high blood pressure. This suggests that HEPA filters not only improve air quality but may also benefit heart health.

These studies have not reported significant negative effects from using HEPA filters, indicating that users generally do not experience serious side effects. Based on this information, HEPA filters appear to be a safe choice for those considering participation in a clinical trial focused on heart health and air quality. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about using HEPA filtration for heart disease because it offers a non-invasive way to potentially improve heart health. Unlike medications or surgical procedures, HEPA filters work by removing tiny particulate matter (PM2.5) from indoor air, which may reduce inflammation and stress on the heart. This approach targets environmental factors contributing to heart disease, offering a unique angle compared to traditional treatments like medications or lifestyle changes. If successful, this could lead to a simple yet effective method to support cardiovascular health by improving the air quality in people's homes.

What evidence suggests that HEPA filtration is effective for heart disease?

Research has shown that HEPA filters can benefit heart health by lowering blood pressure. Studies have found that using HEPA filters significantly reduces systolic blood pressure, the top number in a blood pressure reading. For example, one study noted a 2.8 mm Hg drop in systolic blood pressure with HEPA filters, while a sham filter caused a slight increase. In this trial, participants will experience both HEPA and sham filtration to assess their effects on heart health. This suggests that HEPA filters might help lower heart disease risks. Another study pointed out that these filters can reduce exposure to harmful particles, especially in homes near highways, further supporting their heart health benefits. ^{6 7 8 9 10}

Who Is on the Research Team?

Zhanghua Chen, PhD

Principal Investigator

University of Southern California

Junfeng Zhang, PhD

Principal Investigator

Duke University

Are You a Good Fit for This Trial?

Adults aged 65-84 living in Los Angeles County with a history of ischemic heart disease, clinically stable for the past 6 months, and weighing at least 110 pounds can join. Smokers or those with certain health conditions like active cancer treatments or degenerative diseases are excluded.

Inclusion Criteria

I am between 65 and 84 years old.

Live in the Los Angeles County

You haven't smoked for at least 1 year.

Exclusion Criteria

Your home cannot accommodate air purifiers and air pollution monitors.

I have a degenerative nervous system condition like dementia or Alzheimer's.

Your home already has HEPA filters.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

HEPA Filtration Intervention

Participants receive true HEPA filtration to reduce indoor PM2.5 levels

9 months

3 visits (in-person) before, middle, and after intervention

Wash-out Period

Participants undergo a wash-out period between interventions

3 months

Sham Filtration Intervention

Participants receive sham filtration with HEPA filter removed

9 months

3 visits (in-person) before, middle, and after intervention

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• HEPA filtration
• Sham filtration

Trial Overview The trial is testing if using HEPA air filters in homes can slow down the worsening of atherothrombosis (blood clotting in hardened arteries) compared to sham (fake) filters by reducing fine particle pollution indoors.

How Is the Trial Designed?

Group I: Sham first and HEPA Experimental Treatment 2 Interventions

This group of participants will be assigned to the intervention of sham filtration with HEPA filter removed at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to the HEPA filtration for 9 months.

Group II: HEPA first and sham Experimental Treatment 2 Interventions

This group of participants will be assigned to the intervention of HEPA filtration with the capacity to reduce indoor PM2.5 levels at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to sham filters (air purifier has the same appearance but HEPA filter is removed) for 9 months.

Who Is Running the Clinical Trial?

University of Southern California

Lead Sponsor

Trials

956

Recruited

1,609,000+

Duke University

Collaborator

Trials

2,495

Recruited

5,912,000+

National Institute of Environmental Health Sciences (NIEHS)

Collaborator

Trials

294

Recruited

1,233,000+

Published Research Related to This Trial

Electret filters (EE) initially remove particles more effectively than high-efficiency filters (HE) in the 0.3-3.5 μm size range, but their efficiency decreases significantly over time, dropping to 60% after processing 25 × 10⁴ m³/m² of air.

Portable air cleaners (PAC) with a combination of pre-filters and high-efficiency filters (PR&HE) achieved the highest single-pass efficiency for PM1.0 at 88.6%, indicating that filter combinations can enhance particle removal but may also reduce airflow rates.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room. Ma, H., Shen, H., Shui, T., et al.[2018]

The use of HEPA air filters significantly reduced indoor concentrations of traffic-related airborne particles, which are linked to asthma issues in children.

Children with poorly controlled asthma showed notable improvements in asthma control and quality of life after using HEPA filtration, indicating its potential as an effective intervention for managing asthma symptoms.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

HEPA filtration improves asthma control in children exposed to traffic-related airborne particles. James, C., Bernstein, DI., Cox, J., et al.[2021]

The RAPIDS study demonstrated that high-efficiency particulate arrestance (HEPA) filters significantly reduce indoor PM2.5 concentrations by 60% and personal PM2.5 exposures by 53% among senior citizens in Detroit, indicating their effectiveness in improving air quality and potentially cardiovascular health.

Low-efficiency (HEPA-type) filters also provided benefits, reducing indoor PM2.5 concentrations by 52% and personal exposures by 31%, suggesting that even less efficient filters can contribute to lowering harmful air pollution levels indoors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Reduction of personal PM2.5 exposure via indoor air filtration systems in Detroit: an intervention study. Maestas, MM., Brook, RD., Ziemba, RA., et al.[2021]

HEPA filters demonstrate exceptional filtration efficiency, achieving over 99.97% removal of particles as small as 0.3 micrometers, which is crucial for maintaining air quality.

In tests with bacterial aerosols, three types of HEPA filters achieved 100% bacterial filtration efficiency, while other filters like NBS-95 and NBS-85 also performed well, showing over 99% efficiency.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficiency of bacterial filtration in various commercial air filters for hospital air conditioning. Furuhashi, M.[2006]

Air filtration is an effective environmental control measure for patients with allergic respiratory diseases, with options including whole house systems, portable air cleaners, and specialized sleep zone filters.

High-efficiency particulate air (HEPA) filters in various forms have been shown to provide significant benefits in reducing allergens and improving respiratory health, whether used alone or in combination with other control measures.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effectiveness of air filters and air cleaners in allergic respiratory diseases: a review of the recent literature. Sublett, JL.[2022]

Citations

1. jacc.org jacc.org/doi/10.1016/j.jacc.2025.06.037

Effect of HEPA Filtration Air Purifiers on Blood Pressure A greater percentage of larger reductions in brachial systolic blood pressure was observed among participants who had elevated SBP at the start ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8453120/

A randomized crossover trial of HEPA air filtration to reduce ... This study has the potential to shed light on the value of using portable air filtration in homes close to highways to reduce exposure to TRAP and whether doing ...

3. news-medical.net news-medical.net/news/20250813/HEPA-filtration-reduces-blood-pressure-for-highway-residents.aspx

HEPA filtration reduces blood pressure for highway residents New research reveals that a simple home air purifier could be a powerful tool for cutting high blood pressure and protecting heart health ...

4. endocrinologyadvisor.com endocrinologyadvisor.com/news/use-of-hepa-filters-tied-to-reduced-systolic-bp/

Use of HEPA Filters Tied to Reduced Systolic BP A significant 2.8-mm Hg mean decrease in SBP was seen after HEPA filtration compared with a 0.2-mm Hg increase after sham filtration among ...

5. clinicaltrials.gov clinicaltrials.gov/study/NCT04279249

Home Air Filtration for Traffic-Related Air Pollution Specific Aim 1: To test the effect of HEPA filtration on markers of cardiovascular risk for adults who live near urban highways. 207 participants will be ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/40767818/

Effect of HEPA Filtration Air Purifiers on Blood Pressure Conclusions: The use of in-home HEPA air purifiers resulted in clinically important reductions in SBP for people with elevated SBP in ...

7. acc.org acc.org/About-ACC/Press-Releases/2025/08/06/15/32/Air-Purifiers-May-Reduce-Heart-Risks-for-People-Exposed-to-Traffic-Pollution

Air Purifiers May Reduce Heart Risks for People Exposed ... Researchers found that participants with elevated SBP (>120 mmHg) experienced an average 2.8 mmHg reduction in SBP after one month of HEPA ...

8. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7749091/

and Household-Level Interventions to Reduce Air Pollution ... There is now substantial evidence that HEPA filter air purifiers reduce indoor PM2.5 concentrations and improve subclinical health indicators.

9. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0269749119325060

Different cardiorespiratory effects of indoor air pollution ... The mechanic filters, such as high-efficiency particulate air (HEPA) filtration purifiers, could lower indoor pollution and have cardiorespiratory benefits in ...

10. today.uconn.edu today.uconn.edu/2025/08/air-purifiers-may-reduce-heart-risks-for-people-exposed-to-traffic-pollution/

Air Purifiers May Reduce Heart Risks for People Exposed to ... UConn School of Medicine study finds in-home HEPA air filters significantly lowered systolic blood pressure in adults with elevated readings.