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A Black Carbon‐Tracer Method for Estimating Cooking Organic Aerosol From Aerosol Mass Spectrometer Measurements

Cooking organic aerosol (COA) constitutes a considerable fraction of organic aerosol (OA) in urban environments, yet it is often challenging to resolve COA in summer through positive matrix factorization of unit mass resolution spectra of OA from aerosol mass spectrometer measurements. Here we developed a black carbon‐tracer method for estimating COA in summer. The estimated COA agreed reasonably well with those from other methods. This method can also be applied to other seasons and megacities without substantial emissions from biomass burning and coal combustion. Globally, much higher COA concentrations in China and India than those in North America and Europe were observed, while the COA contributions were comparable (15.5–20%), highlighting the importance of COA in urban areas. Considering the rapidly increased aerosol mass spectrometer measurements worldwide, this method has significant implications for a better source apportionment of OA and also benefits the health studies associated with cooking exposure.