Fig. 3From: Electron microscopic and spectroscopic analysis of airborne ultrafine particles: its effects on the cell viabilityX-ray photoelectron spectroscopy analysis comparing the “whole particles” with “large particles”. a–d Chemical composition analyzed by X-ray photoelectron spectroscopy (XPS): black profile, “whole particles”; red profile, “large particles.” Analysis was done to detect: carbon, oxygen, and nitrogen (a); iron, silicon, and aluminum (b); calcium and potassium (c); sodium and magnesium (d). Note that these representative results were taken from the data of five independent XPS analysis with three independent preparations of UFPsBack to article page