On the effect of upwind emission controls on ozone in Sequoia National Park

Ozone (O3) air pollution in Sequoia National Park (SNP) is among the worst of any national park in the US. SNP is located on the western slope of the Sierra Nevada Mountains downwind of the San Joaquin Valley (SJV), which is home to numerous cities ranked in the top 10 most O3-polluted in the US. Here, we investigate the influence of emission controls in the SJV on O3 concentrations in SNP over a 12-year time period (2001–2012). We show that the export of nitrogen oxides (NOx) from the SJV has played a larger role in driving high O3 in SNP than transport of O3. As a result, O3 in SNP has been more responsive to NOx emission reductions than in the upwind SJV city of Visalia, and O3 concentrations have declined faster at a higher-elevation monitoring station in SNP than at a low-elevation site nearer to the SJV. We report O3 trends by various concentration metrics but do so separately for when environmental conditions are conducive to plant O3 uptake and for when high O3 is most common, which are time periods that occur at different times of day and year. We find that precursor emission controls have been less effective at reducing O3 concentrations in SNP in springtime, which is when plant O3 uptake in Sierra Nevada forests has been previously measured to be greatest. We discuss the implications of regulatory focus on high O3 days in SJV cities for O3 concentration trends and ecosystem impacts in SNP.</p

Identifying Social Norms using Coordination Games: Why Does Dictator Game Sharing Vary?

We explore the influence of social norms on behavior. To do so, we introduce a method for identifying norms, based on the property that social norms reflect social consensus regarding the appropriateness of different possible behaviors. We demonstrate that the norms we elicit, along with a simple model combining concern for norm-compliance with utility for money, predict changes in behavior across several variants of the dictator game in which behavior changes substantially following the introduction of minor contextual variations. Our findings indicate that people care not just about monetary payoffs but also care about the social appropriateness of any action they take. Our work also suggests that a social norm is not always a single action that should or should not be taken, but rather a profile of varying degrees of social appropriateness for different available actions