Beijing Indoor Air Purifier Intervention Study

Beijing Indoor Air Purifier Intervention Study

This study aimed to assess the impact of air filtration on indoor air quality and cardio-pulmonary health in residents living in high outdoor pollution settings in Beijing.

Inclusion Criteria:

• Global Initiative for Chronic Obstructive Lung Disease criteria (mild to moderate, GOLD stage I~II;
• severe to very severe, GOLD stage III~IV) quit smoking for at least 1 year;
• a ratio of pre-bronchodilator forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) equal to or less than 0.70 and an increase of FEV1 with the use of 400μg of albuterol of less than 12% of the pre-bronchodilator one;
• no history of asthma or any other active lung disease.
• Subjects were free from exacerbations for at least 6 weeks.

Exclusion Criteria:

• Patients with heart pacemaker,
• heart failure with bundle-branch block,
• recent myocardial infarction (in the last 12 weeks) and
• anticoagulant therapy