After informed consent, their baseline FMD of brachial artery will be measured as well as lung function. FMD of brachial artery will be measured within 5 mins of use of e-cigarette to reflect the acute effects of e-cigarette on systemic endothelial dysfunction. Bronchoscopy with BAL, blood and urine sampling will be performed. This will enable us to measure the baseline inflammation and markers of cellular injury without inhaled LPS. At 24 hours the subject will return and lung function will be measured and blood sampling will be performed.