The impact of bark beetle infestations on monoterpene emissions and secondary organic aerosol formation in western North America

Over the last decade, extensive beetle outbreaks in western North America have destroyed over 100 000 km2 of forest throughout British Columbia and the western United States. Beetle infestations impact monoterpene emissions through both decreased emissions as trees are killed (mortality effect) and increased emissions in trees under attack (attack effect). We use 14 yr of beetle-induced tree mortality data together with beetle-induced monoterpene emission data in the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM) to investigate the impact of beetle-induced tree mortality and attack on monoterpene emissions and secondary organic aerosol (SOA) formation in western North America. Regionally, beetle infestations may have a significant impact on monoterpene emissions and SOA concentrations, with up to a 4-fold increase in monoterpene emissions and up to a 40% increase in SOA concentrations in some years (in a scenario where the attack effect is based on observed lodgepole pine response). Responses to beetle attack depend on the extent of previous mortality and the number of trees under attack in a given year, which can vary greatly over space and time. Simulated enhancements peak in 2004 (British Columbia) and 2008 (US). Responses to beetle attack are shown to be substantially larger (up to a 3-fold localized increase in summertime SOA concentrations) in a scenario based on bark-beetle attack in spruce trees. Placed in the context of observations from the IMPROVE network, the changes in SOA concentrations due to beetle attack are in most cases small compared to the large annual and interannual variability in total organic aerosol which is driven by wildfire activity in western North America. This indicates that most beetle-induced SOA changes are not likely detectable in current observation networks; however, these changes may impede efforts to achieve natural visibility conditions in the national parks and wilderness areas of the western United States.National Science Foundation (U.S.) (ATM- 0929282)National Science Foundation (U.S.) (ATM-0939021)National Science Foundation (U.S.) (ATM-0938940)United States. Dept. of Energy. Office of Scienc

Enhanced Trophic Transfer of Chlorpyrifos from Resistant Hyalella azteca to Inland Silversides (Menidia beryllina) and Effects on Acetylcholinesterase Activity and Swimming Performance at Varying Temperatures

This excel workbook contains data from a study of trophic transfer of radiolabeled (C-14) chlorpyrifos from organophosphate-resistant Hyalella azteca to a known predator, the Inland silverside Menidia beryllina. Fish were fed 15 dosed (~ 1 ng/animal) or control H. azteca for 7 days at two temperatures, 18 and 23°C, to simulate changes anticipated under global climate change (GCC). Following feeding, fish were analyzed for critical swimming speed (Ucrit) and brain acetylcholinesterase (AChE) activity. Total chlorpyrifos concentrations, as well as percent parent compound as a a measure of biotransformation, were measured in both H. azteca and M. beryllina

Airborne particles in Swansea, UK : their collection and characterization

Urban air particulate matter (PM) has previously been associated with a variety of adverse health effects. It is now believed that the smallest particles, ultrafine or nanoparticles, are linked to the greatest health effects. The physicochemistry of these particles is likely to provide information regarding their toxicity. Therefore, the aim of this study was to further the understanding of the heterogeneous and changing particle concentrations in urban air, in conjunction with gaining an understanding of the physicochemistry of the particles. A Dekati electrical low-pressure impactor was used to collect the particles and real-time data in a busy traffic corridor in Swansea, Wales, over a period of 10 nonconsecutive weeks. Particle concentrations in the street canyon were analyzed and particle physicochemistries investigated using a variety of techniques. Particle number concentrations were found to vary both diurnally and from day to day in the traffic corridor. Of all particles, the nano to fine size fraction was consistently identified in the highest concentrations (maximum: 140,000 particles cm-3). Particle physicochemistry was found to vary as a function of size, with larger particles exhibiting a greater variety of morphologies (and consequently particle types) and associated metals.Peer reviewe