Atomic force microscopy for the analysis of environmental particles

In this study, atomic force microscopy (AFM) was evaluated as an alternative to electron microscopy for analysis of nano- to micron-sized environmental particles, such as atmospheric aerosols. The wide range of conditions under which AFM can be conducted allows for “reactive” imaging. For example, collected particles can be imaged under ambient conditions and re-imaged as a function of time in order to evaluate changes. Chemical information about individual particles can be obtained in two ways: (1) by monitoring relative reaction rates when the sample is exposed to a reactive gas, and (2) by determination of the magnitude of interaction forces between the AFM tip and individual particles. The combined advantages of digital, three-dimensional morphological information, no vacuum requirements, virtually no sample preparation, and real-time imaging during reaction, make AFM an excellent technique for analysis of environmental particles.