Climate Change In The Casco Bay Watershed: Past, Present, And Future

This report describes how the climate of Casco Bay watershed in Maine has changed over the past century and how the future climate of the region is likely to be affected by human emissions of heat-trapping greenhouse gases that are warming the planet. Overall, the region has been getting warmer and wetter over the last century, and these trends have increased over the last four decades. To generate future projections for Portland, Farmington, and Lewiston, simulated temperature and precipitation from four climate models were fitted to local, long-term weather observations. Unknowns regarding fossil fuel consumption were accounted for by using two future scenarios. The scenarios describe climate in terms of temperature and precipitation for three future periods: the near-term, 2010-2039, mid-century, 2040-2069, and end-of-century, 2070-2099. All changes are relative to a historical baseline, 1970-1999. Some future changes are inevitable, so smart choices must be made to ensure our society and our environment will be able to adapt to coming change. But with prompt action, many of the most extreme consequences of climate change could be avoided or their worst impacts reduced

Projecting policy – relevant metrics for high summertime ozone pollution events over the 1 Eastern United States due to climate and emission changes during the 21st century

Over the eastern United States (EUS), nitrogen oxides (NOx) emission controls have led to improved air quality over the past two decades, but concerns have been raised that climate warming may offset some of these gains. Here we analyze the effect of changing emissions and climate, in isolation and combination, on EUS summertime surface ozone (O3) over the recent past and the 21st century in an ensemble of simulations performed with the Geophysical Fluid Dynamics Laboratory CM3 chemistry-climate model. The simulated summertime EUS O3 is biased high but captures the structure of observed changes in regional O3 distributions following NOx emission reductions. We introduce a statistical bias correction, which allows derivation of policy-relevant statistics by assuming a stationary mean state bias in the model, but accurate simulation of changes at each quantile of the distribution. We contrast two different 21st century scenarios: (i) representative concentration pathway (RCP) 4.5 and (ii) simulations with well-mixed greenhouse gases (WMGG) following RCP4.5 but with emissions of air pollutants and precursors held fixed at 2005 levels (RCP4.5_WMGG). We find under RCP4.5 no exceedance of maximum daily 8 hour average ozone above 75 ppb by mid-21st century, reflecting the U.S. NOx emissions reductions projected in RCP4.5, while more than half of the EUS exceeds this level by the end of the 21st century under RCP4.5_WMGG. Further, we find a simple relationship between the changes in estimated 1 year return levels and regional NOx emission changes, implying that our results can be generalized to estimate changes in the frequency of EUS pollution events under different regional NOx emission scenarios

Effect of regional precursor emission controls on long-range ozone transport – Part 1: Short-term changes in ozone air quality

Observations and models demonstrate that ozone and its precursors can be transported between continents and across oceans. We model the influences of 10% reductions in anthropogenic nitrogen oxide (NOx) emissions from each of nine world regions on surface ozone air quality in that region and all other regions. In doing so, we quantify the relative importance of long-range transport between all source-receptor pairs, for direct short-term ozone changes. We find that for population-weighted concentrations during the three-month "ozone-season", the strongest inter-regional influences are from Europe to the Former Soviet Union, East Asia to Southeast Asia, and Europe to Africa. The largest influences per unit of NOx reduced, however, are seen for source regions in the tropics and Southern Hemisphere, which we attribute mainly to greater sensitivity to changes in NOx in the lower troposphere, and secondarily to increased vertical convection to the free troposphere in tropical regions, allowing pollutants to be transported further. Results show, for example, that NOx reductions in North America are ~20% as effective per unit NOx in reducing ozone in Europe during summer, as NOx reductions from Europe itself. Reducing anthropogenic emissions of non-methane volatile organic compounds (NMVOCs) and carbon monoxide (CO) by 10% in selected regions, can have as large an impact on long-range ozone transport as NOx reductions, depending on the source region. We find that for many source-receptor pairs, the season of greatest long-range influence does not coincide with the season when ozone is highest in the receptor region. Reducing NOx emissions in most source regions causes a larger decrease in export of ozone from the source region than in ozone production outside of the source region

Assessment of knowledge and intake of artificial sweeteners among type II diabetic individuals and perspectives of registered dieticians in India

Background: The beneficial effects of artificial sweeteners (AS) on the prevention of non-communicable diseases have been noticed with various ambiguity outcomes. The knowledge of AS among consumers and healthcare providers can facilitate in making informed decisions about its usage. Therefore, this study, aimed to assess the knowledge, attitude and practice and usage of AS among type II diabetic patients and the conception of registered dieticians on usage of AS, as a sugar substitute. Study design: The study was a cross-sectional, descriptive study. Methods: The data on AS consumption, discomforts, and health consequences of chronic consumption from type-II diabetics (n = 51) and the opinion of dieticians (n = 53) on AS recommendations were gathered using a pretested questionnaire online through email via docs.google.com. The association or correlation between AS consumption, discomforts, and awareness was analysed by chi-square and Spearman correlation tests. Results: The results indicated that study subjects consumed AS in the form of tabletop sweeteners (86.3%), sweets (35.3%), and beverages (31.4%). Saccharin (29.5%), sucralose (27.3%), and aspartame (27.3%) were the major tabletop sweeteners consumed. 77% of subjects consumed AS from 1-3 years, while others from 4-5 years. 59% of participants consumed AS without consultation, and only 5.9% expressed discomfort after consumption. However, a significant association was noticed between discomfort and beverage consumption. 58.8% were unaware of the health consequences, and KAP analysis showed that knowledge was negatively associated with practice and attitude was positively associated with it. The survey among dieticians revealed that 73.6% were not recommending AS, mainly due to less reliable information, particularly regarding safety issues, and ambiguity on the use of AS in dietetic practice. While others consumed AS over natural sugars in glycemic control, weight management, and lifestyle factors. Conclusion: Majority of diabetic patients did not know the side effects of chronic AS consumption, while dieticians had divergent views on AS due to insufficient research regarding the safety and side effects of chronic AS consumption. Therefore, more precise studies are required to understand the consequences of chronic consumption of AS on health benefits

Effect of regional precursor emission controls on long-range ozone transport – Part 2: Steady-state changes in ozone air quality and impacts on human mortality

Large-scale changes in ozone precursor emissions affect ozone directly in the short term, and also affect methane, which in turn causes long-term changes in ozone that affect surface ozone air quality. Here we assess the effects of changes in ozone precursor emissions on the long-term change in surface ozone via methane, as a function of the emission region, by modeling 10% reductions in anthropogenic nitrogen oxide (NOx) emissions from each of nine world regions. Reductions in NOx emissions from all world regions increase methane and long-term surface ozone. While this long-term increase is small compared to the intra-regional short-term ozone decrease, it is comparable to or larger than the short-term inter-continental ozone decrease for some source-receptor pairs. The increase in methane and long-term surface ozone per ton of NOx reduced is greatest in tropical and Southern Hemisphere regions, exceeding that from temperate Northern Hemisphere regions by roughly a factor of ten. We also assess changes in premature ozone-related human mortality associated with regional precursor reductions and long-range transport, showing that for 10% regional NOx reductions, the strongest inter-regional influence is for emissions from Europe affecting mortalities in Africa. Reductions of NOx in North America, Europe, the Former Soviet Union, and Australia are shown to reduce more mortalities outside of the source regions than within. Among world regions, NOx reductions in India cause the greatest number of avoided mortalities per ton, mainly in India itself. Finally, by increasing global methane, NOx reductions in one hemisphere tend to cause long-term increases in ozone concentration and mortalities in the opposite hemisphere. Reducing emissions of methane, and to a lesser extent carbon monoxide and non-methane volatile organic compounds, alongside NOx reductions would avoid this disbenefit

Beneficial role of antioxidants during liver transplantation

Background & Objectives: Initial graft dysfunction, an event mainly due to the unavoidable ischemia-reperfusion (I/R) injury of the transplanted organ, is one of the most important early post-operative problems in liver transplantation. It is well known that antioxidants significantly improves early allograft function and both graft and patient survival. Thus, the present study was carried out to evaluate the exact role of antioxidants during liver transplantation. Method: We assessed serum lipid peroxide (as oxidant), serum superoxide dismutase (SOD) and serum vitamin E (as antioxidant) in 30 patients undergoing liver transplantation and equal numbers of healthy subjects. Results: We found that the concentration of serum lipid peroxide (MDA) was significantly increased and antioxidants were significantly decreased in all stages of liver transplant patients as compared with healthy controls (P<0.001). On reperfusion there was pronounced consumption of antioxidants and highly elevated levels of serum lipid peroxide was seen than in those of pre-reperfusion and post-reperfusion stages (P<0.0001) of liver transplantations. Conclusion: Antioxidants can be used in liver transplantation patients to effectively reduce the severity of reperfusion injury and to improve short-term allograft function and patient survival

Sensitivity of tropospheric oxidants to biomass burning emissions: implications for radiative forcing

Biomass burning is one of the largest sources of trace gases and aerosols to the atmosphere and has profound influence on tropospheric oxidants and radiative forcing. Using a fully coupled chemistry-climate model (GFDL AM3), we find that co-emission of trace gases and aerosol from present-day biomass burning increases the global tropospheric ozone burden by 5.1% and decreases global mean OH by 6.3%. Gas and aerosol emissions combine to increase CH4 lifetime nonlinearly. Heterogeneous processes are shown to contribute partly to the observed lower ΔO3/ΔCO ratios in northern high latitudes versus tropical regions. The radiative forcing from biomass burning is shown to vary nonlinearly with biomass burning strength. At present-day emission levels, biomass burning produces a net radiative forcing of −0.19 W/m2 (−0.29 from short-lived species, mostly aerosol direct and indirect effects, +0.10 from CH4- and CH4-induced changes in O3 and stratospheric H2O) but increases emissions to over 5 times present levels would result in a positive net forcing