Cardiovascular health and particulate vehicular emissions: a critical evaluation of the evidence

A major public health goal is to determine linkages between specific pollution sources and adverse health outcomes. This paper provides an integrative evaluation of the database examining effects of vehicular emissions, such as black carbon (BC), carbonaceous gasses, and ultrafine PM, on cardiovascular (CV) morbidity and mortality. Less than a decade ago, few epidemiological studies had examined effects of traffic emissions specifically on these health endpoints. In 2002, the first of many studies emerged finding significantly higher risks of CV morbidity and mortality for people living in close proximity to major roadways, vs. those living further away. Abundant epidemiological studies now link exposure to vehicular emissions, characterized in many different ways, with CV health endpoints such as cardiopulmonary and ischemic heart disease and circulatory-disease-associated mortality; incidence of coronary artery disease; acute myocardial infarction; survival after heart failure; emergency CV hospital admissions; and markers of atherosclerosis. We identify numerous in vitro, in vivo, and human panel studies elucidating mechanisms which could explain many of these cardiovascular morbidity and mortality associations. These include: oxidative stress, inflammation, lipoperoxidation and atherosclerosis, change in heart rate variability (HRV), arrhythmias, ST-segment depression, and changes in vascular function (such as brachial arterial caliber and blood pressure). Panel studies with accurate exposure information, examining effects of ambient components of vehicular emissions on susceptible human subjects, appear to confirm these mechanisms. Together, this body of evidence supports biological mechanisms which can explain the various CV epidemiological findings. Based upon these studies, the research base suggests that vehicular emissions are a major environmental cause of cardiovascular mortality and morbidity in the United States. As a means to reduce the public health consequences of such emissions, it may be desirable to promulgate a black carbon (BC) PM2.5 standard under the National Ambient Air Quality Standards, which would apply to both on and off-road diesels. Two specific critical research needs are identified. One is to continue research on health effects of vehicular emissions, gaseous as well as particulate. The second is to utilize identical or nearly identical research designs in studies using accurate exposure metrics to determine whether other major PM pollutant sources and types may also underlie the specific health effects found in this evaluation for vehicular emissions

The effect of giving verbal reasons during or after the solution of practice problems on transfer performance.

The effect of giving verbal reasons during or after the solution of practice problems on transfer performance

The Unusual Weather in 2009 in Illinois Created Major Economic Impacts

Abnormal weather conditions existed in Illinois during every month from March 2009 through November 2009. March–August conditions were exceptionally wet and cool with frequent cloudy skies. The fall months brought a dry September, a cold and wet October, and a warm and dry November. Wet, cool spring conditions delayed planting of major crops and led to flooding along many rivers. Summer temperatures were nearly 3 degrees F below normal, reducing the use of air conditioning but delaying crop maturity. Summer 2009 was rated as the 8th wettest and 11th coldest in Illinois since 1895. A shift to warm and dry weather in September, followed by cool and wet conditions in October sustained flooding and delayed harvesting of Illinois crops. Conditions shifted again in November, becoming warm and relatively dry, so corn and soybean harvesting moved forward rapidly. In early December, most soybeans had been harvested, but 15 percent of the corn crop was still in the fields. The crop harvest in 2009 was rated as the slowest ever in Illinois. The unusual weather during the 2009 crop season led to worries over production, yet near-record-high yields were recorded for corn (174 bu/acre) and soybeans (46 bu/acre). These large yields helped farm incomes, but delays in corn drying and tillage (preparing soil for future planting) increased costs. In addition, high yields across the Corn Belt lowered crop prices, which also decreased farm incomes. Storms in 2009 were more frequent than usual and resulted in extensive property damage in Illinois. Included were four record-setting rainstorms and several hailstorms. Storms in northern Illinois produced large hailstones of 2 inches in diameter, frequent cases of high winds with gusts greater than 60 mph, and 18 tornadoes. More than 400 million dollars in property losses were reported along with 120 million dollars in crop losses from severe storms. Flooding on most rivers occurred various times during March–November 2009. The Illinois River was above flood stage for 89 consecutive days, setting a new record. Heavy rains of 2009 helped bring Lake Michigan’s level up to near average for the first time since 2004. Wet and cloudy conditions affected human behavior, including a reduction in retail shopping. Construction and repair of highways and buildings were delayed, a negative outcome in a struggling economic time across the nation. The unusual weather in 2009 persisted through December, and some of the 2009 weather impacts continued into the following months of 2010. Corn harvesting in northern Illinois continued into January 2010, soil tillage awaited drier conditions in the spring of 2010, and fertilizer applications in the fall of 2009 were delayed until 2010. Flooding on the Illinois River and several of its tributaries also continued into January 2010.published or submitted for publicationis peer reviewe

2004: Comparison of observations with idealized model results for a method to resolve winter lake-effect mesoscale morphology

ABSTRACT Forecasters in the Great Lakes region have for several decades recognized a general relationship of wind speed and overlake fetch to lake-effect snowstorm morphology. A recent study using idealized mesoscale model simulations of lake-effect conditions over circular and elliptical lakes showed the ratio of wind speed to maximum fetch distance (U/L) may be used to effectively predict lake-effect snowstorm morphology. The current investigation provides an assessment of the U/L criteria using observational datasets. Previously published Great Lakes lake-effect snowstorm observational studies were used to identify events of known mesoscale morphology. Hindcasts of nearly 640 lake-effect events were performed using historical observations with U/L as the predictor. Results show that the quantity U/L contains important information on the different mesoscale lake-effect morphologies; however, it provides only a limited benefit when being used to predict mesoscale morphology in real lake-effect situations. The U/L criteria exhibited the greatest probability of detecting lake-effect shoreline band events, often the most intense, but also experienced a relatively large number of false hindcasts. For Lakes Erie and Ontario the false hindcasts and biases were reduced and shoreline band events that occurred under higher wind speed conditions were better identified. In addition, the Great Lakes Environmental Research Laboratory ice cover digital dataset was used in combination with observations from past events to assess the impact of ice cover on the use of U/L as a predictor of lake-effect morphology. Results show that hindcasts using the U/L criteria were slightly improved when the reduction of open-water areas due to lake ice cover was taken into account

F.: Mesoscale boundary layer and heat flux variations over pack ice-covered Lake

ABSTRACT The development of extensive pack ice fields on the Great Lakes significantly influences lake-effect storms and local airmass modification, as well as the regional hydrologic cycle and lake water levels. The evolution of the ice fields and their impacts on the atmospheric boundary layer complicates weather forecasters' ability to accurately predict late-season lake-effect snows. The Great Lakes Ice CoverAtmospheric Flux (GLICAF) experiment was conducted over Lake Erie during February 2004 to investigate the surface-atmosphere exchanges that occur over midlatitude ice-covered lakes. GLICAF observations taken by the University of Wyoming King Air on 26 February 2004 show a strong mesoscale thermal link between the lake surface and the overlying atmospheric boundary layer. Mesoscale atmospheric variations that developed over the lake in turn influenced heat exchanges with the surface. Boundary layer sensible and latent heat fluxes exhibited different relationships to variations in surface pack ice concentration. Turbulent sensible heat fluxes decreased nonlinearly with increases in underlying lake-surface ice concentration such that the largest decreases occurred when ice concentrations were greater than 70%. Latent heat fluxes tended to decrease linearly with increasing ice concentration and had a reduced correlation. Most current operational numerical weather prediction models use simple algorithms to represent the influence of heterogeneous ice cover on heat and moisture fluxes. The GLICAF findings from 26 February 2004 suggest that some currently used and planned approaches in numerical weather prediction models may significantly underestimate sensible heat fluxes in regions of high-concentration ice cover, leading to underpredictions of the local modification of air masses and lake-effect snows

Transitions in boundary layer meso-convective structures: An observational case study

ABSTRACT Boundary layer rolls over Lake Michigan have been observed in wintertime conditions predicted by many past studies to favor nonroll convective structures (such as disorganized convection or cellular convection). This study examines mechanisms that gave rise to transitions between boundary layer rolls and more cellular convective structures observed during a lake-effect snow event over Lake Michigan on 17 December 1983. The purposes of this study are to better understand roll formation in marine boundary layers strongly heated from below and examine the evolution of snowfall rate and mass overturning rate within the boundary layer during periods of convective transition. A method of quantifying the uniformity of convection along the roll axes, based on dual-Doppler radar-derived vertical motions, was developed to quantify changes in boundary layer convective structure. Roll formation was found to occur after (within 1 h) increases in low-level wind speeds and speed shear primarily below about 0.3z i , with little change in directional shear within the convective boundary layer. Roll convective patterns appeared to initiate upstream of the sample region, rather than form locally near the downwind shore of Lake Michigan. These findings suggest that either rolls developed over the upwind half of Lake Michigan or that the convection had a delayed response to changes in the atmospheric surface and wind forcing. Mass overturning rates at midlevels in the boundary layer peaked when rolls were dominant and gradually decreased when cellular convection became more prevalent. Radar-estimated aerial-mean snowfall rates showed little relationship with changes in convective structure. However, when rolls were dominant, the heaviest snow was more concentrated in updraft regions than during more cellular time periods