There is no side-stream vapor, only the exhaled vapor from users, which contains a fraction of the compounds inhaled by the vaper
These tests can help identify whether your rhinitis symptoms have an allergic component
Some flavourings, especially those containing diacetyl, have been linked to lung diseases like "popcorn lung" when inhaled, though the presence of diacetyl in vapes has yet to cause this particular issue that was established when flavouring popcorn in popcorn factories (hence 'popcorn lung')

Previous studies have shown that mouse M1-type macrophages are pro-inflammatory, whereas M2-type macrophages are anti-inflammatory, release IL-10, and exhibit significant phagocytic activity ( Macrophages can secrete elastolytic enzymes, including MMP-2, MMP-9, and MMP-12 ( Monocytes from COPD patients exhibit a stronger chemotactic response to CXCL1 than monocytes from smokers and non-smokers ( It has been shown that in healthy individuals and smokers, corticosteroids inhibit the release of CXCL8, TNF- and MMP-9 from macrophages, thereby alleviating the inflammatory response, but in patients with COPD, where the inflammatory response is mainly mediated by cytokines, chemokines and proteases, corticosteroid use is ineffective ( Both alveolar-derived macrophages and monocyte-derived macrophages in patients with COPD exhibit reduced phagocytic uptake of bacteria, which may be the result of long-term colonization of the lower airways by bacteria such as Haemophilus influenzae or Streptococcus pneumoniae ( 3.3 Neutrophils Increased sputum and BALF neutrophilia is a typical feature of COPD, and this neutrophil-induced inflammation can caused by regular exposure to cigarette smoke, infectious agent and oxidative stress ( Neutrophils secrete several serine proteases including neutrophil elastase (NE), cathepsin G, proteinase-3, MMPs and myeloperoxidase (MPO) which may contribute to the alveolar damage ( It has been suggested that the size and extent of the neutrophil traffic may be related to the pathological changes that occur in individuals with COPD in case of emphysema ( The above findings have implications for the precise treatment of COPD
