H. A. Scheeren

TL;DR: The Mediterranean Intensive Oxidant Study, performed in the summer of 2001, uncovered air pollution layers from the surface to an altitude of 15 kilometers, causing air pollution standards to be exceeded throughout the region.

TL;DR: It is shown that agricultural burning and especially biofuel use enhance carbon monoxide concentrations and Fossil fuel combustion and biomass burning cause a high aerosol loading, which gives rise to extensive air quality degradation.

Abstract: We present an analysis of trace gas correlations in the lowermost stratosphere. In-situ aircraft measurements of CO, N(2)O, NO(y) and O(3) Obtained during the STREAM 1997 winter campaign, have been used to investigate the role of cross-tropopause mass exchange on tracer-tracer relations. At altitudes several;kilometers above the local tropopause, undisturbed stratospheric air was found with NO(y)/NO(y)* ratios close to unity, NO(y)/O(3) about 0.003 - 0.006 and CO mixing ratios as low as 20 ppbv (NO(y)* is a proxy for total reactive nitrogen derived from NO(y)-N(2)O relations measured in the stratosphere). Mixing of tropospheric-air into the lowermost stratosphere has been identified by enhanced ratios of NO(y)/NO(y)* and NO(y)/O(3), and from scatter plots of CO versus O(3). The enhanced NO(y)/O(3) ratio in the lowermost stratospheric mixing zone points to a reduced efficiency of O(3) formation from aircraft NO(x) emissions.

TL;DR: In this article, the Proton Transfer Reaction Mass Spectrometer (PTR-MS) was used for airborne measurements of volatile organic compounds (VOC) over the tropical rainforest in Surinam.

TL;DR: Ongoing emissions cast doubt upon recent reports of a strong and unexpected negative trend in OH during the 1990s and a previously calculated higher OH abundance in the Southern Hemisphere compared to the Northern Hemisphere.