Portable Air Cleaners Could Limit Fine Particulate Exposure During Rehab

July 2, 2020

A new pilot study called CRAFT is examining the potential of portable air cleaners for limiting exposure to fine particulate matter in patients enrolled in cardiac rehabilitation.

A new pilot study is underlining the potential usefulness of in-home portable air cleaners to help reduce exposure to fine particulate matter (PM) for patients undergoing cardiac rehabilitation.

While relatively small in size, results of the Cardiac Rehabilitation Air Filter Trial (CRAFT) study indicate using an in-home portable air cleaner was associated with a reduction in levels of PM2.5 exposure among patients participating in cardiac rehabilitation at Michigan Medicine.




“We show here for the first time that providing cardiac patients with PAC for use in their homes results in approximately a 40 percent reduction in personal-level exposure to PM2.5 air pollution,” said study investigator Robert L. Bard, MS, of Michigan Medicine, in a statement.

With the impact of exposure to air pollutants on cardiovascular health well-established, Bard and a team of colleagues from Michigan Medicine performed the CRAFT study to investigate the efficacy portable air cleaner usage in patients with heart disease living at home. The pilot phase of the trial, which included 20 patients, was designed as a randomized, double-blind, cross-over trial of patients taking part in an outpatient cardiac rehabilitation program. 



Portable air cleaners used in the study were HAP8650B-NU-1 devices from Holmes. The air filters used in the study were true HEPA filters able to remove an estimated 99.97% of airborne particles at 0.3 μm.

Patients included in the study were provided with 2 portable air cleaners and instructed to run both in their home continuously for 5 days—with 1 in their bedroom and the other in their main living space. Four days later, and after a return cardiac rehabilitation visit, patients were given a PM2.5 monitor for the following 24 hours. After a 1-week washout period, patients were crossed over to the opposite treatment arm. 



Of note, the PM2.5 monitor given to patients recorded 10-minute long PM2.5 exposure averages and patients were asked to keep a log of their activities every 30 minutes to explain monitoring results. 



The mean age of the study cohort was 70.8±9.6 years, 95% were white, and 4 were women. Additionally, mean BMI was 29.2±5.4 kg/m2, mean systolic blood pressure was 118±13 mmHg, and mean diastolic blood pressure was 65±10 mmHg. In regard to risk factors, 90% suffered from hyperlipemia, 60% had hypertension, and 35% were diabetic. 



In regard to prior cardiovascular event, 45% of patients suffered a myocardial infarction, 45% had undergone a percutaneous coronary intervention, 5% under coronary artery bypass surgery, and 5% suffered a stroke. Additionally, all 20 were on antihypertensive medications and 19 of 20 were receiving statins. At the end of the trial, 18 patients had completed both arms.




Compared to those in the sham arm, use of in-home portable air cleaners was associated with significantly lowered 24-hour PM2.5 exposures; with rates indicating a reduction of 43.8% (−12.2 μm; 95% CI, −24.2 to −0.2). An additional set of sensitivity analyses, which examined the effect with outlying patients removed, found outliers did not influence the overall results of the trial.

Investigators note the results of the study support the design of future outcomes trials examining the use of portable air cleaners in. a cardiac rehabilitation setting.

This study, “Reduced Fine Particulate Matter Air Pollution Exposures Using In-Home Portable Air Cleaners,” was published in the Journal of Cardiopulmonary Rehabilitation and Prevention.