Nanostructures in gas suspension

Nanostructures in gas suspension grow by clustering of atoms and radicals, by surface condensation, and by agglomeration. We show that photoelectron s pectroscopy may be performed on nanostructures in their natural gaseous env ironment, that is, without application of a vacuum or precipitation onto a substrate. Moreover, the photoelectric yield induced by pulsed lasers deliv ers a fingerprint of the bulk and surface properties and their dynamics. Th e most important application is to the nanostructures formed in combustion of fossil fuels found abundantly in the air in which we live. These nanostr uctures are important to the physics and chemistry of the atmosphere and fu rthermore act as vehicles transporting a number of dangerous compounds deep into the human respiratory tract. We show how such particles may be identi fied according to their source and measured with portable sensors. We also present data taken in several large cities around the globe and quantify th e impact on human health.