No abstract

[1] During the 2000 Texas Air Quality Study (TexAQS) and 2006 Texas Air Quality Study (TexAQS II) field experiments, aircraft measured ozone concentrations upwind, across, and downwind of the Houston and Dallas urban areas. Background ozone transported into Houston contributed, on average, approximately 50% and 66% of the total ozone on 8-h ozone exceedance days investigated by aircraft flights during TexAQS and TexAQS II, respectively. Analysis of a flight over Dallas on one exceedance day showed that transported ozone constituted 72% of the total ozone concentration. The aircraft measurements show that these two major metropolitan areas can be brought close to exceeding the 1997 8-h National Ambient Air Quality Standard for ozone of 0.08 ppm solely by the ozone contribution of regional transport before additional contribution from local sources. Large local contributions were also observed, particularly in Houston. Transport contributions to Dallas area ozone were quantified using the Comprehensive Air Quality Model with Extensions (CAMx) photochemical grid model and source apportionment methods. Model-predicted ozone concentrations were compared to ozone measurements from the aircraft and the surface monitoring network, and showed agreement on the importance of regional transport and local ozone formation. These results emphasize the benefits of regional control strategies, and suggest that local controls alone may not be sufficient to ensure attainment of the 8-h ozone standard in Houston and Dallas.

International audienceThe CAMx photochemical grid model was used to model ozone (O3) and particulate matter (PM) over a European modeling domain for calendar year 2006 as part of the Air Quality Model Evaluation International Initiative (AQMEII). The CAMx base case utilized input data provided by AQMEII for emissions, meteorology and boundary conditions. Sensitivity of model outputs to input data was investigated by using alternate input data and changing other important modeling assumptions including the schemes to represent photochemistry, dry deposition and vertical mixing. Impacts on model performance were evaluated by comparisons with ambient monitoring data. Base case model performance for January and July 2006 exhibited under-estimation trends for all pollutants both in winter and summer, except for SO2. SO2 generally had little bias although some over-estimation occurred at coastal locations and this was attributed to incorrect vertical distribution of emissions from marine vessels. Performance for NOx and NO2 was better in winter than summer. The tendency to under-predict daytime NOx and O3 in summer may result from insufficient NOx emissions or overstated daytime dilution (e.g., too deep planetary boundary layer) or monitors that are located near sources (e.g., roadside monitors). Winter O3 was biased low and this was attributed to a low bias in the O3 boundary conditions. PM10 was widely under-predicted in both winter and summer. The poor PM10 was influenced by underestimation of coarse PM emissions. Sensitivities of O3 concentrations to precursor emissions are quantified using the decoupled direct method in CAMx. The results suggest that O3 production over the central and southern Europe during summer is mostly NOx-limited but for a more northerly city, London, O3 production can be limited either by NOx or VOC depending upon daily meteorological conditions

This review highlights the key messages from the KDIGO (Kidney Disease: Improving Global Outcomes) clinical practice guidelines for care of kidney transplant recipients, which were written to be global guidelines irrespective of the regulatory, fiscal, cultural, socioeconomic, or geographical environment. The distillation of 3168 randomized control trials, 7543 cohort studies, and 1609 reviews led to recommendations rated by the strength of supporting evidence and the quality of the data from A to D. Despite this, the quality of the evidence is surprisingly low for the majority of decisions that are routinely taken in all transplant units throughout the world, highlighting the needs for properly designed randomized controlled trials. The principle areas covered in the guidelines include immunosuppression, management of acute rejection, monitoring of the patient and graft, chronic allograft injury, kidney bio psy, nonadherence, vaccination, infectious diseases, cardiovascular risk management, malignancy, bone disease, pediatric growth, lifestyle, fertility, and mental health. This review highlights a number of these areas for consideration focusing on the different types of evidence that we use in daily clinical practice.

Following U.S. Tier 3 emissions and fuel sulfur standards for gasoline-fueled passenger cars and light trucks, these vehicles are expected to contribute less than 6% of the summertime mean daily maximum 8-hr ozone and less than 7% and 4% of the winter and summer mean 24-hr PM2.5 in the eastern U.S. in 2030. On days with elevated ozone or PM2.5 at four major urban areas, these vehicles contribute less than 7% of ozone and less than 5% of PM2.5, with sources outside North America and U.S. area source emissions constituting some of the main contributors to ozone and PM2.5, respectively.