Tropospheric ozone assessment report: Global ozone metrics for climate change, human health, and crop/ecosystem research.

Assessment of spatial and temporal variation in the impacts of ozone on human health, vegetation, and climate requires appropriate metrics. A key component of the is the consistent calculation of these metrics at thousands of monitoring sites globally. Investigating temporal trends in these metrics required that the same statistical methods be applied across these ozone monitoring sites.

Post-sedation events in children sedated for dental care.

Moderate oral sedation is used in pediatric dentistry for safe delivery of dental care to children. However, there is a paucity of data on the effects of pediatric dental sedations after discharge of children from the dental office. The purpose of this study was to evaluate and compare the incidence of adverse events occurring with meperidine and hydroxyzine versus midazolam alone 8 and 24 hours after sedation in pediatric dental patients.

Management of avulsed permanent incisors with closed apices and prolonged extraoral dry time.

This article reports the clinical management and outcome of two avulsed permanent incisors that were kept dry for 42 hours. Dental trauma guidelines were followed and clinically successful outcomes were seen until seven months of follow-up. The factors contributing to successful management of this case despite the extreme clinical circumstances were attributed to pulp extirpation prior to replantation, doxycycline soak, fluoride soak, and timely endodontic treatment.

Primary tooth radicular resorption as a consequence of self-corrected ectopic eruption: 2 unusual cases.

Resorption of the distal root of primary second molars is a common consequence of ectopically erupting permanent first molars. Here, we report 2 unusual cases of primary molar root resorption caused by reversible (self-correcting) ectopic eruption of premolar and canine teeth. In both cases, severe pathological resorption of the mesial roots of primary molars was detected on routine dental radiographs, and the affected molars remained asymptomatic until exfoliation.

Spontaneous regression of congenital epulis: a case report and review of the literature.

Introduction: Congenital epulis is a rare lesion found on the alveolar process of a newborn child, diagnosed soon after birth. The lesion has a site predilection for the anterior maxillary alveolar process and a 9:1 sex predilection for females. Once diagnosed the traditional management of the lesion has been surgical excision under general anesthesia.

The use of critical levels for determining plant response to ozone in Europe and in North America.

Critical levels to determine plant response to ozone (O3) have been used in Europe since the 1980s, utilizing the concentration-based AOT40 to relate plant response to ambient O3 exposure. More recently, there has been progress in Europe toward utilizing flux-based critical levels, because plant response is more closely related to O3 uptake than to the amount of O3 in ambient air. Flux-based critical levels are plant species specific; data for parameterization of flux-based critical levels models are lacking for most plant species.

Impacts of air pollution and climate change on forest ecosystems--emerging research needs.

Outcomes from the 22nd meeting for Specialists in Air Pollution Effects on Forest Ecosystems "Forests under Anthropogenic Pressure--Effects of Air Pollution, Climate Change and Urban Development", September 10-16, 2006, Riverside, CA, are summarized. Tropospheric or ground-level ozone (O3) is still the phytotoxic air pollutant of major interest. Challenging issues are how to make O3 standards or critical levels more biologically based and at the same time practical for wide use; quantification of plant detoxification processes in flux modeling; inclusion of multiple environmental stresses in critical load determinations; new concept development for nitrogen saturation; interactions between air pollution, climate, and forest pests; effects of forest fire on air quality; the capacity of forests to sequester carbon under changing climatic conditions and coexposure to elevated levels of air pollutants; enhanced linkage between molecular biology, biochemistry, physiology, and morphological traits.

Air quality at a snowmobile staging area and snow chemistry on and off trail in a Rocky Mountain subalpine forest, Snowy Range, Wyoming.

A study was begun in the winter of 2000-2001 and continued through the winter of 2001-2002 to examine air quality at the Green Rock snowmobile staging area at 2,985 m elevation in the Snowy Range of Wyoming. The study was designed to evaluate the effects of winter recreation snowmobile activity on air quality at this high elevation site by measuring levels of nitrogen oxides (NO( x ), NO), carbon monoxide (CO), ozone (O(3)) and particulate matter (PM(10) mass). Snowmobile numbers were higher weekends than weekdays, but numbers were difficult to quantify with an infrared sensor.

Evaluation of storage and filtration protocols for alpine/subalpine lake water quality samples.

Many government agencies and other organizations sample natural alpine and subalpine surface waters using varying protocols for sample storage and filtration. Simplification of protocols would be beneficial if it could be shown that sample quality is unaffected. In this study, samples collected from low ionic strength waters in alpine and subalpine lake inlets and outlets in the western United States were used to evaluate (1) effects of refrigerated storage time on the chemistry of unfiltered samples, and (2) differences in sample filtration protocols.

Air pollution, precipitation chemistry and forest health in the Retezat Mountains, Southern Carpathians, Romania.

In the Retezat Mountains concentrations of O3, NO2 and SO2 in summer season 2000-2002 were low and below toxicity levels for forest trees. While NH3 concentrations were low in 2000, the 2001 and 2002 concentrations were elevated indicating possibility for increased N deposition to forest stands. More than 90% of the rain events were acidic with pH values <5.

New international long-term ecological research on air pollution effects on the Carpathian Mountain forests, Central Europe.

An international cooperative project on distribution of ozone in the Carpathian Mountains, Central Europe was conducted from 1997 to 1999. Results of that project indicated that in large parts of the Carpathian Mountains, concentrations of ozone were elevated and potentially phytotoxic to forest vegetation. That study led to the establishment of new long-term studies on ecological changes in forests and other ecosystems caused by air pollution in the Retezat Mountains, Southern Carpathians, Romania and in the Tatra Mountains, Western Carpathians on the Polish-Slovak border.

Estimating CO(2) flux from snowpacks at three sites in the Rocky Mountains.

Soil surface CO(2) flux (F(s)) is the dominant respiratory flux in many temperate forest ecosystems. Snowpacks increase this dominance by insulating the soil against the low temperature to which aboveground components are exposed. However, measurement of F(s) in winter may be impeded by snow cover.