Satellite remote sensing of air quality has evolved dramatically over the last decade. Global observations are now available for a wide range of species including aerosols, tropospheric O3, tropospheric NO2, CO, HCHO, and SO2. Capabilities for satellite remote sensing of these species in the boundary layer are reviewed for current instruments, along with physical processes affecting their accur...

The paper provides an overview on the use of photoacoustic sensors based on semiconductor laser sources for the detection of trace gases. We review the results obtained using standard, differential and quartz enhanced photoacoustic techniques.

The uptake of trace gases by atmospheric aerosols and cloud droplets plays a critical role in the atmospheric chemistry of both the troposphere and stratosphere. The transfer of gaseous species through the interfacial boundary layer and into the liquid phase involves a number of closely entwined processes, including: gas phase diffusion, mass accommodation, evaporation, Henry's law solubility, ...

Selected ion flow tube mass spectrometry, (SIFT-MS), is a technique for simultaneous real-time quantification of several trace gases in air and exhaled breath. It relies on chemical ionization of the trace gas molecules in air/breath samples introduced into helium carrier gas, using H(3)O(+), NO(+) and O(2)(+) reagent (precursor ions). Reactions between the precursor ions and the trace gas mole...

This paper deals with an absorption spectroscopic method for trace gas measurements called DOAS (Diierential Optical Absorption Spectroscopy) from a statistical point of view. The DOAS technique is an absorption spectrosco-pic technique to measure trace gas concentrations. It is capable of detecting and measuring a number of important trace gases at tropospheric concentration levels by observin...

The determination of trace water in gas samples, such as isobutene, chloromethane (polymeric staple gases) and SF6 by a conventional Karl Fischer coulometer is very difficult, because of the adsorption of trace water on the surface of sample pipe, the gasification of the liquefied samples, and the migration of moisture into the measuring cell from the surroundings. To solve these problems, we i...

findings of this study are (i) PTR-MS evidence for the flow dependency of exhaled acetone; (ii) changing minute ventilation can both increase and decrease the concentrations of selected exhaled trace gases; and (iii) concentrations of certain volatiles were not significantly altered by respiratory manoeuvres in healthy volunteers. These preliminary observations may have important implications r...