Natural Resources Defense Council

About: Natural Resources Defense Council is a nonprofit organization based out in New York, New York, United States. It is known for research contribution in the topics: Public health & Climate change. The organization has 177 authors who have published 292 publications receiving 11799 citations. The organization is also known as: NRDC.

Toxicity testing in the 21st century: a vision and a strategy

Abstract: With the release of the landmark report Toxicity Testing in the 21st Century: A Vision and a Strategy, the U.S. National Academy of Sciences, in 2007, precipitated a major change in the way toxicity testing is conducted. It envisions increased efficiency in toxicity testing and decreased animal usage by transitioning from current expensive and lengthy in vivo testing with qualitative endpoints to in vitro toxicity pathway assays on human cells or cell lines using robotic high-throughput screening with mechanistic quantitative parameters. Risk assessment in the exposed human population would focus on avoiding significant perturbations in these toxicity pathways. Computational systems biology models would be implemented to determine the dose-response models of perturbations of pathway function. Extrapolation of in vitro results to in vivo human blood and tissue concentrations would be based on pharmacokinetic models for the given exposure condition. This practice would enhance human relevance of test results, and would cover several test agents, compared to traditional toxicological testing strategies. As all the tools that are necessary to implement the vision are currently available or in an advanced stage of development, the key prerequisites to achieving this paradigm shift are a commitment to change in the scientific community, which could be facilitated by a broad discussion of the vision, and obtaining necessary resources to enhance current knowledge of pathway perturbations and pathway assays in humans and to implement computational systems biology models. Implementation of these strategies would result in a new toxicity testing paradigm firmly based on human biology.

Relative contributions of greenhouse gas emissions to global warming

Abstract: IN the past few years, many workers have noted that the combined effect on climate of increases in the concentrations of a large number of trace gases could rival or even exceed that of the increasing concentration of carbon dioxide1–3. These trace gases, principally methane, nitrous oxide and chlorofluorocarbons, are present at concentrations that are two to six orders of magnitude lower than that of carbon dioxide, but are important because, per molecule, they absorb infrared radiation much more strongly than carbon dioxide. Indeed a recent study4 shows that trace gases are responsible for 43% of the increase in radiative forcing from 1980 to 1990 (Fig. 1). An index to compare the contribution of various 'greenhouse' gas emissions to global warming is needed to develop cost-effective strategies for limiting this warming. Estimates of relative contributions to additional greenhouse forcing during particular periods do not fully take into account differences in atmospheric residence times among the important greenhouse gases. Here we extend recent work on halocarbons5,6 by proposing an index of global warming potential for methane, carbon monoxide, nitrous oxide and CFCs relative to that of carbon dioxide. We find, for example, that methane has, per mole, a global warming potential 3.7 times that of carbon dioxide. On this basis, carbon dioxide emissions account for 80% of the contribution to global warming of current greenhouse gas emissions, as compared with 57% of the increase in radiative forcing for the 1980s.

The 2006 California Heat Wave: Impacts on Hospitalizations and Emergency Department Visits

Abstract: Deaths from heat waves in the United States and Europe have been described in a number of studies (Basu and Samet 2002; Donoghue et al 2003; Hajat et al 2006; Kinney et al 2008; Medina-Ramon et al 2006; Naughton et al 2002; Semenza et al 1996; Vandentorren et al 2004), but there have been relatively few studies of heat-related morbidity (Kovats et al 2004; Mastrangelo et al 2006; Nitschke et al 2007; Semenza et al 1999) Increased mortality during heat waves has been attributed mainly to cardiovascular illness (13–90%) and diseases of the cerebrovascular (6–52%) and respiratory systems (up to 14%) (Kilbourne 1999), especially among the elderly (Kovats and Ebi 2006) Heat stress can rapidly become life threatening, especially among those with limited access to immediate medical attention (Mastrangelo et al 2006) People with severe heat stroke symptoms have little time to seek treatment in emergency departments (EDs) or hospitals (Kovats and Ebi 2006; Kovats et al 2004; Naughton et al 2002; Semenza et al 1996) Previous studies have reported different patterns of morbidity in contrast to mortality patterns during heat waves Hospital admissions during heat waves have been reported to increase among both older and younger adults, especially among adults living in institutions or engaging in outdoor activities involving exertion (Johnson et al 2005; Kovats and Ebi 2006) Most admissions were for heat-related conditions, including heat exhaustion and heat stroke, dehydration and electrolyte disorders, and acute renal failure (Kovats and Ebi 2006; Mastrangelo et al 2006; Semenza 1999; Semenza et al 1999) Some increases in admissions for neurologic conditions and mental illnesses (Kovats and Ebi 2006) and ambulance transport for violence-related causes (Nitschke et al 2007) have been reported A study of emergency hospital admissions in London (Kovats et al 2004) failed to find statistically significant increases in total emergency hospital admissions during extreme heat, although increases were found for respiratory and renal illnesses in children 0–4 years of age and for respiratory illness in people ≥ 75 years of age In other studies, hospitalizations for cardiovascular diseases have decreased slightly (3%) during heat waves (Mastrangelo et al 2006) The relationship between heat and morbidity in any specific area may be affected by local population demographics, economic well-being, underlying disease risk, the presence of vulnerable subpopulations, weather variability, physiologic acclimatization, and locally available adaptations (Kinney et al 2008) During mid- to late July 2006, an extreme heat wave affected much of the state of California, breaking daily maximum temperature records at seven sites and exceeding minimum temperature records at 11 meteorologic stations, especially from 16 through 26 July Both the intensity and duration of the heat wave were exceptional, and records for most consecutive days reaching ≥ 100°F were broken in the Central Valley region (Kozlowski and Edwards 2007) The statewide mean temperature for July 2006 was 4°F above the long-term climatologic average, with some stations in central and southern California recording the warmest July on record (Edwards 2006) County coroners and medical examiners reported at least 140 deaths from extreme heat recorded between 15 July and 1 August 2006 (California Department of Health Services 2007) This event offered a unique opportunity to study heat-related morbidity patterns in a large US study area (> 163,000 square miles) and population (37 million California residents) Better understanding of the patterns of morbidity during heat waves is an important tool for public health practitioners, because more intense, more frequent, and longer duration heat waves are projected for the coming decades (Meehl and Tebaldi 2004) The health impacts of climate change are gaining considerable attention (Frumkin et al 2008), with increases in heat wave–related illness and death among the most likely related challenges to public health (Confalonieri et al 2007; Jackson and Naumoff Shields 2008; Kovats and Hajat 2008) The 2006 heat wave may thus represent a sentinel event of a major public health challenge associated with climate change To evaluate the effects of extreme heat on morbidity during the 2006 heat wave, the California Department of Public Health and the Natural Resources Defense Council investigated hospitalizations and ED visits for certain illnesses to discern regional patterns by diagnosis, age, and race/ethnicity One of the goals of the present study was to learn which illnesses are exacerbated by heat waves in California and lead people to seek medical attention, thus providing opportunities for early intervention and public education to prevent heat-related illness and death

Location efficiency: neighborhood and socio-economic characteristics determine auto ownership and use - studies in chicago, los angeles and san francisco

Abstract: Auto ownership and mileage per car are shown to vary in a systematic and predictable fashion in response to neighborhood urban design and socio-economic characteristics in the Chicago, Los Angeles, and San Francisco regions. In all three cases, average auto ownership is primarily a function of the neighborhood's residential density, average per capita income, average family size and the availability of public transit. Similarly, the average annual distance driven per car is a strong function of density, income, household size and public transit, and a weaker function of the pedestrian and bicycle friendliness of the community. The similarity of these relationships among the three metro areas, despite their differences in geography and age, suggests that similar relationships may be consistent throughout the United States or worldwide. The application of the results to other metro areas is discussed. The dependence of driving on the policy-related variables of residential density, transit access, and pedestrian and bicycle-friendliness may provide policy makers with additional tools for reducing the costs and environmental impacts of transportation.