Indoor Air Quality and Respiratory Symptoms in Former Smokers

Assessing the Effect of Different Efficiency Indoor Air Filters on Respiratory Symptoms in Former Smokers

The investigators will conduct a randomized, controlled, double-blind, crossover trial to determine whether the presence of a portable high-efficiency indoor air filter in the bedroom reduces respiratory symptoms in former smokers compared with placebo. The primary outcomes will be change in St. George's Respiratory Questionnaire - COPD (SGRQ-C) score associated with using a portable high-efficiency indoor air filter during the study period. Secondary outcomes of COPD exacerbations and hospitalizations, daily step counts, medication changes, spirometry, and cardiovascular outcomes will also be assessed.

Hypothesis/Research Questions:

This study will determine whether the presence of a portable high-efficiency indoor air filter in the bedroom improves respiratory symptoms (based on St. George's Respiratory Questionnaire - COPD - SGRQ-C score) during a period of high air pollution compared with placebo in former smokers with respiratory symptoms.

The primary outcome will be the change in SGRQ-C score associated with using a portable high-efficiency indoor air filter during the study period.

Secondary outcomes will assess the effect of using a portable high-efficiency indoor air filter on healthcare utilization, other symptom scores, COPD exacerbation frequency, medication use, median daily step counts, inflammatory markers, oxygenation, indoor particulate counts and indoor-outdoor particulate count difference, and pulmonary function tests.

Baseline descriptive statistics will report baseline air filter type, duration of use, and particulate weight prior to study enrollment.

Evaluation of change in symptom scores and other secondary outcomes from baseline to study air filter (Visit 1 vs. Visit 2).

Inclusion Criteria:

• history of smoking
• Do not currently smoke and no one currently smokes inside the home
• history of exacerbation or development of respiratory symptoms (e.g.cough, sputum production, chest tightness, exertional dyspnea, etc.) with periods of high outdoor air pollution ("inversions")
• Age 40 or older
• Access to Wi-Fi
• Access to a cell phone, tablet or personal computer

Exclusion Criteria:

• active tobacco use of subject
• active tobacco use in the home
• pre-existing use of a HEPA filter in the subject's bedroom