A growing body of evidence has found that mortality rates are positively correlated with social inequalities, air pollution, elevated ambient temperature, availability of medical care and other factors. This study develops a model to predict the mortality rates for different diseases by county across the US. The model is applied to predict changes in mortality caused by changing environmental factors. A total of 3,110 counties in the US, excluding Alaska and Hawaii, were studied. A subset of 519 counties from the 3,110 counties was chosen by using systematic random sampling and these samples were used to validate the model. Step-wise and linear regression analyses were used to estimate the ability of environmental pollutants, socio-economic factors and other factors to explain variations in county-specific mortality rates for cardiovascular diseases, cancers, chronic obstructive pulmonary disease (COPD), all causes combined and lifespan across five population density groups. The estimated models fit adequately for all mortality outcomes for all population density groups and, adequately predicted risks for the 519 validation counties. This study suggests that, at local county levels, average ozone (0.07 ppm) is the most important environmental predictor of mortality. The analysis also illustrates the complex inter-relationships of multiple factors that influence mortality and lifespan, and suggests the need for a better understanding of the pathways through which these factors, mortality, and lifespan are related at the community level.

News U.S. taxpayers are, in effect, subsidizing the Gulf of Mexico's dead zone, an area of coastal waters where dissolvedoxygen concentrations fall to less than 2 parts per million every summer, according to a new paper published in ES&T (pp 5410-5418). These findings don't bode well for the Gulf, as more and more acres of land are planted with corn to meet the growing U.S. demand for alternative fuels.Scientists studying nutrient inputs that feed the Gulf's hypoxic zone have known that certain intensively farmed areas in the upper Midwest leak more nitrogen derived from fertilizers than others. Now, there's a new twist. Farmers in areas with the highest rates of fertilizer runoff tend to receive the biggest payouts in federal crop subsidies, says Mary Booth, lead author of the paper and a former senior scientist with the Environmental Working Group. What's more, they have fewer acres enrolled in conservation programs compared with other parts of the Mississippi River basin (MRB).Modeling the major sources of nitrate in the MRB, Booth and her colleagues found that fertilizer runoff is responsible for 59% of springtime nitrate loading to the Gulf, atmospheric deposition for 17%, animal waste for 13%, and municipal wastewater for 11%.These findings are consistent with earlier analyses but go a step further by homing in on the seasonal aspects of nitrogen flux rather than annual loading, says Richard Alexander, with the U.S. Geological Survey. "Spring flux is what matters most in predicting the formation of the [Gulf's] hypoxia zone," he adds.Booth's team added data from NaNcy R abal ais, louisiaNa uNiveRsities MaRiNe coNsoRtiuM