Clinical Trial of Air Cleaners to Improve Indoor Air Quality and COPD Health

Objectives (include all primary and secondary objectives)

Specific Aim #1: To determine whether an air cleaner intervention to improve home air quality will improve respiratory symptoms, quality of life, lung function and reduce risk of exacerbations in former smokers with COPD.

Hypothesis: An intervention using high-efficiency particulate air (HEPA) and carbon filter air cleaners in homes of former smokers with COPD will improve respiratory symptoms, quality of life, and lung function and reduce risk of COPD exacerbations compared with placebo (sham air cleaners).

Specific Aim #2: To determine whether an air cleaner intervention to improve home air quality will be associated with intermediate outcome measures known to be linked with long term outcomes in COPD, including airway and systemic markers of inflammation and oxidative stress, in former smokers with COPD.

Hypothesis 2: An intervention using HEPA and carbon filter air cleaners in homes of formers smokers with COPD will be associated with lower levels of markers of inflammation and oxidative stress known to be associated with adverse outcomes in patients with COPD.

This research is being done to learn whether an air cleaner intervention to improve home air quality (particulate matter (PM) and nitrogen dioxide (NO2) reduction) will improve respiratory symptoms, quality of life, lung function, and reduce risk of exacerbations in former smokers with COPD.

The investigators will place air pollution monitors in the home to measure the air quality over five 1-week periods (at 3 month and 1 week pre-intervention, and 1 week, 3 months and 6 months post-intervention). During each week of monitoring, the investigators will ask that a diary be kept of breathing and how the participants are feeling every day.

Participant will have 5 home visits and 5 clinic visits and monthly telephone calls during this time to see how the participant is feeling. One week after each home visit, the monitoring equipment will be picked up. After the 2nd monitoring period, active or sham air cleaners will be placed in home.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 40 years,
* Physician diagnosis of COPD,
* Global Initiative for Obstructive Lung Disease (GOLD) Stage II-IV disease with Forced Expiratory Volume (FEV1)/ Forced Vital Capacity (FVC) ≤70% and FEV1 (% predicted) \<80%,
* Tobacco exposure ≥ 10 pack-years, and
* Former smoker. We will employ a combination of self-report and a biochemical marker to identify former-smokers. Exhaled CO (eCO) will be used as a marker of smoking status, as it is easy to perform, provides immediate data and is non-invasive. Former-smokers will be those who report no current smoking in the past 1 year AND have exhaled CO levels ≤ 6ppm. This threshold was chosen to maximize the chance of distinguishing true smokers and ex-smokers (\>95%).

Exclusion Criteria:

* Chronic systemic corticosteroids (≥ 3 months continuous use in past 12 months),
* Other chronic lung disease including asthma,
* Living in location other than home (e.g., long term care facility) and
* Home owner or home occupant planning to move or change residence within the study period.