Table 1.

Studies characterizing the size and composition of PM accumulated on leaf surfaces.

Category	Parameters	Method	Reference
Size fractions	PM1, PM2.5, PM10	SEM	[23]
	PM2.5, PM10	Vacuum filtration	[23]
	PM2.5, PM2.5-10, PM10-100	Elution-filtration- weighing	[25]
	PM0.2-3, PM3-10, PM10-100	Elution-filtration- weighing	[26]
	PM1, PM1-2.5, PM2.5-5	Sweep-resuspension- particle size spectrometer	[27]
	Average size	X-ray microscope	[27]
Ion concentrations	Mass fractions of 10 water-soluble ions	IC	[28]
	Concentrations of NO3− and SO42− in wash-off suspensions	IC	[29]
Elemental compositions	Concentrations of 23 elements (Na, Mg, Al, Si, P, etc.)	SEM/EDX	[30]
	Concentrations of 12 elements (Ca, Mg, P, Al, Si, etc.)	SEM/EDX	[31]
	Concentrations of 16 metal elements (Ba, Cd, Cr, Cs, Cu, etc.)	ICP-MS	[32]
	Concentrations of Cr, Cd, Ni, Cu, and Pb	ICP-OES	[33]