There is rapidly growing interest in the use of market-based (MB) instruments in environmental policy. The papers in this session discuss three relatively new areas for such policies: groundwater contamination, nonpoint source surface-water pollution and carbon sequestration. The papers point out the potential for MB policies in these areas, but significant challenges remain. This comment highl...

The knowledge of the contribution bd(d) to the artificial sky luminance in a given point of the sky of a site produced by the sources beyond a given distance d from it is important to understand the behaviour of light pollution in diffusely urbanized areas and to estimate which fraction of the artificial luminance would be regulated by norms or laws limiting the light wasted upward within prote...

Soil erosion associated with non-point source pollution is viewed as a process of land degradation in many terrestrial environments. Careful monitoring and assessment of land use variations with different temporal and spatial scales would reveal a fluctuating interface, punctuated by changes in rainfall and runoff, movement of people, perturbation from environmental disasters, and shifts in agr...

Nitrogen oxides (NO x = NO + NO2) are a primary component of air pollution-a leading cause of premature death in humans and biodiversity declines worldwide. Although regulatory policies in California have successfully limited transportation sources of NO x pollution, several of the United States' worst-air quality districts remain in rural regions of the state. Site-based findings suggest that ...