FEV1	Forced Expiratory Volume in 1 s
FEV1/FVC	The ratio of FEV1 to Forced Vital Capacity
FEF25–75%	Forced Expiratory Flow between 25% and 75% of vital capacity
FEFmax	Maximal Forced Expiratory Flow
PEF	Peak Expiratory Flow
VOCs	Volatile Organic Compounds
EBC	Exhaled Breath Condensate
GC-MS	Gas Chromatography–Mass Spectrometry
LC-MS	Liquid Chromatography–Mass Spectrometry
IL	Interleukin
TNF-α	Tumor Necrosis Factor-alpha
IFN-γ	Interferon-gamma
FeNO	Fractional exhaled Nitric Oxide
TSLP	Thymic Stromal Lymphopoietin
GINA	Global Initiative for Asthma
NICE	National Institute for Health and Care Excellence
NMR	Nuclear Magnetic Resonance
PLS-DA	Partial Least-Squares Discriminant Analysis
SERS	Surface-Enhanced Raman Scattering
DNA	Deoxyribonucleic
RNA	Ribonucleic Acid