Comparison of land-use regression models between Great Britain and the Netherlands

Land-use regression models have increasingly been applied for air pollution mapping at typically the city level. Though models generally predict spatial variability well, the structure of models differs widely between studies. The observed differences in the models may be due to artefacts of data and methodology or underlying differences in source or dispersion characteristics. If the former, more standardised methods using common data sets could be beneficial. We compared land-use regression models for NO₂ and PM_10, developed with a consistent protocol in Great Britain (GB) and the Netherlands (NL).Models were constructed on the basis of 2001 annual mean concentrations from the national air quality networks. Predictor variables used for modelling related to traffic, population, land use and topography. Four sets of models were developed for each country. First, predictor variables derived from data sets common to both countries were used in a pooled analysis, including an indicator for country and interaction terms between country and the identified predictor variables. Second, the common data sets were used to develop individual baseline models for each country. Third, the country-specific baseline models were applied after calibration in the other country to explore transferability. The fourth model was developed using the best possible predictor variables for each country.A common model for GB and NL explained NO₂ concentrations well (adjusted R² 0.64), with no significant differences in intercept and slopes between the two countries. The country-specific model developed on common variables for NL but not GB improved the prediction.The performance of models based upon common data was only slightly worse than models optimised with local data. Models transferred to the other country performed substantially worse than the country-specific models. In conclusion, care is needed both in transferring models across different study areas, and in developing large inter-regional LUR models.     

Book reviews

Environment Systems and Decisions -     

Endosulfan transport: I. Integrative assessment of airborne and waterborne pathways

To reduce endosulfan (C9H6O3Cl6S; 6,7,8,9,10,10-hexachloro-1,5, 5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide) contamination in rivers and waterways, it is important to know the relative significances of airborne transport pathways (including spray drift, vapor transport, and dust transport) and waterborne transport pathways (including overland and stream runoff). This work uses an integrated modeling approach to assess the absolute and relative contributions of these pathways to riverine endosulfan concentrations. The modeling framework involves two parts: a set of simple models for each transport pathway, and a model for the physical and chemical processes acting on endosulfan in river water. An averaging process is used to calculate the effects of transport pathways at the regional scale. The results show that spray drift, vapor transport, and runoff are all significant pathways. Dust transport is found to be insignificant. Spray drift and vapor transport both contribute low-level but nearly continuous inputs to the riverine endosulfan load during spraying season in a large cotton (Gossypium hirsutum L.)-growing area, whereas runoff provides occasional but higher inputs. These findings are supported by broad agreement between model predictions and observed typical riverine endosulfan concentrations in two rivers.     

Tropical Diversity and Conservation

The superior diversity of the tropics is well known and, for the largest marine and continental areas, there appears to be a positive relationship between area and species diversity (richness). There are certain portions of the tropics, however, in which species diversity has reached unusually high levels. Such areas apparently function as centers of evolutionary origin. In the ocean the largest of the four tropical shelf regions is the Indo-West Pacific, which stretches almost two thirds of the distance around the globe. Within that expanse by far the greatest diversity is found within the relatively small East Indies Triangle. From the Triangle an evolutionary radiation has reached many other parts of the marine world. On land the Neotropical, Ethiopian, and Oriental biogeographic regions demonstrate very high levels of species diversity. Various major groups of animals and plants have originated in these regions and subsequently spread to other parts of the world. There is no accepted scientific agreement on a conservation strategy for these areas. By focusing our attention on centers of origin, we can save the areas containing species that apparently have the greatest evolutionary potential.     

Mineral consumption in the UK, 1945–1980: A statistical analysis

Trends in the UK consumption of 12 metallic and 19 non-metallic minerals are examined for the period 1945–1980. Comparisons are drawn between these trends and developments in per capita GDP, total world consumption and UK mineral processing capacity. Although the consumption of most minerals has shown a tendency to stagnate or decline in recent years, taking the post-war period as a whole the consumption of non-metallics has displayed a faster and more sustained growth than that of metallics; thus their share of the total value of minerals consumed in the UK has increased significantly.