Air Pollution People and Plants : An Introduction

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Surface Level Ozone and its Adverse Effects on Crops and Forests: A Need for an Interdisciplinary Understanding

Surface level ozone (O3) is clearly a global scale problem with regard to its adverse effects on crops, forests and native, terrestrial plant ecosystems. Photochemists and meteorologists are continuing to define the chemistry and physics of the prevalence of O3 at the ground level. Similarly, plant scientists in the U.S. and Europe have examined the effects of O3 on crops and tree seedlings or saplings through large-scale studies. Examples include the U.S. National Crop Loss Assessment Network (NCLAN), the U.S. EPA’s (Environmental Protection Agency’s) San Bernardino National Forest Photochemical Oxidant Study, European Open-top Chambers Programme (EOTCP), and several ongoing EU (European Union) projects. In addition, there have been studies on mature tree responses through field measurements and by simulation modeling

Deuterium as a Novel Tracer for Determining Moisture Sources in Building Systems

Many current problems in moisture-related deterioration of housing are found in the building envelope. Components such as interior surfaces, siding, millwork, sheathing, and framing are damaged due to excessive moisture accumulation, which leads to potential biodeterioration (mold and decay). The monetary and health implications of such widespread failures are severely impacting the housing industry. In certain individual cases of wood wetting, the source of liquid water is readily determined: typically, a failure of external sealing allows direct ingress of precipitation into the wall system. There is, however, still a debate on the role of subsequent moisture movement or condensation (from water vapor movement to a cool surface) in wall and roofing system failures. Here we show that deuterium-labeled water introduced into wood through either liquid or vapor phase can be recovered via distillation or mechanical expression. The use of deuterium as a moisture tracer can assist in determining the origin of moisture (particularly through the vapor phase transition), provide insight into current recommended practices for moisture control in buildings, and assess the application of current moisture modeling on existing moisture failures