Frank de Leeuw

Deposition of the most acidifying components in The Netherlands during the period 1980–1986

Abstract Detailed maps of the deposition of acidifying components in The Netherlands are presented. The deposition was estimated from measurements of concentrations in the atmosphere and precipitation. Lack of information on the concentration of ammonia and ammonium in air made it impossible to estimate dry deposition. Therefore, these were estimated by model calculations. The nationwide averaged deposition of total (potential) acid in 1980 was ca . 5800 mol H + ha −1 a −1 . The most important acidifying components are sulphur oxides, nitrogen oxides and ammonia and their reaction products. Sulphur compounds ( SO x ) contributed about 49%, reduced nitrogen species ( NH x ) 23% and oxidized nitrogen species ( NO ty ) 28% to the total deposition. Wet deposition contributes 30% to the total deposition. The spatial distribution of the total deposition shows a gradient over The Netherlands with highest values in the south and lowest in the north. In 1986 the total deposition was estimated to be ca. 4900 mol H + ha −1 a −1 (40% SO x , 32% NO y and 28% NH x . The decrease is mainly the result of the lower SO x deposition. The relative contribution of inland emissions to the deposition in The Netherlands is about 41%. About 30% of the NH, deposition is due to foreign sources; for SO x this is about 80% and for NO y 65%. About 80% of Dutch emissions is deposited outside The Netherlands. The net export of SO x decreased between 1980 and 1985 from 150 kt a −1 to 35 kt a −1 , while the net export of NO y ( ca . 280 kt a −1 ) and NH, ( ca . 155 kt a −1 ) has remained constant over the period 1980–1986.

Spatial Mapping of Ozone and SO2 Trends in Europe

This article investigates the spatial mapping of temporal trends in air quality for all of Europe. Such spatially distributed maps provide information for policy making and for understanding the spatial character of air quality trends. Previous trend studies have concentrated on individual, or groups of, monitoring sites looking at the trends of these. In this study use is made of statistical interpolation methods that combine observed and modelled data in an optimised way. Log-normal residual kriging with multiple linear regression is used to produce annual maps of air quality indicators for ozone (AOT40; Accumulated Dose of Ozone Over a Threshold of 40 ppb) and SO(2) (annual mean) for the period 1996-2005. Trends in these maps are then calculated and their significance and uncertainty are assessed. The methodology is effectively used for mapping SO(2) trends to a significant level in most of Europe. However, trends in AOT40 are less clearly defined since the uncertainty is generally of the same order as, or greater than, the calculated trends. A general north to south gradient in AOT40 trends can be seen, with downward trends in the UK and Scandinavia but upward trends in the Mediterranean region.

Initial assessment of the hazards and risks of new chemicals to man and the environment

Abstract This paper describes the initial hazard and risk assessment process for new substances at the National Institute of Public Health and Environmental Protection (RIVM) in The Netherlands. This assessment pertains to both man and the environment and is performed within the framework of the European Community (EC) Directive 79/831/EEC and the ensuing Dutch Chemical Substances Act. The present paper is restricted to the assessment of the hazards of new substances on the basis of the base set, i.e. tests required at a market or production volume up to 100 tonnes per year or 500 tonnes cumulative. Step by step the essential elements of the hazard assessment process are discussed: organizational aspects, data requirements, the determination of the acceptability of the data received, the scientific evaluation of the test methods and results, the exposure assessment and the comparison of exposure and toxicity data. Requirements for further testing following the initial assessment are also discussed.

Contributions of traffic emissions to mesoscale NOx and O3 concentrations

Abstract The contributions of traffic related emissions to the long-term and short-term mesoscale concentrations of O3 and NOx in The Netherlands are estimated by means of atmospheric transport models. Both an Eulerian grid model with simplified chemistry and a trajectory model with a more complex chemistry are used. The contribution of traffic emissions to the NOx concentrations differs largely from its contribution to the NO2 concentrations as a result of the non-linear NOx chemistry (e.g. the photostationary equilibrium). On a yearly basis the contribution of national traffic emissions to the averaged concentrations in The Netherlands are 30% for NOx and 25% for NO2. During winter episodes these contributions are 12–15% for NOx and 3% for NO2. During a summer episode inland traffic emissions account for 35–55% of NOx and NO2 concentrations. The national traffic emissions have only a minor contribution (4%) to the O3 peak values observed in The Netherlands; European traffic emissions are estimated to be responsible for 26% of the O3 peak values.

Current State of Particulate Air Quality

Abstract To reduce health impacts from airborne particulate matter (PM), the World Health Organization (WHO) has issued guidelines. Multiple jurisdictions such as the European Union (EU) and the United States (US) have promulgated regulations. However, areas remain in nonattainment. Data from the EU, US, and from across south and southeastern Asia are reviewed for their concentrations, trends, and compliance with their regulatory standards. PM concentrations are generally being reduced. In the US, road dust has been substantially reduced as a contributor to coarse particles through the use of extensive street sweeping. However, non-exhaust emissions represent significant fractions of coarse PM. In the EU, many locations are now in compliance with the air quality directive but far from the WHO guidelines. However, other areas still need to reduce ambient concentrations and it is likely that reducing road dust contributions will be needed to achieve acceptable air quality.

Sub-grid Variability and Its Impact on Air Quality Exposure Assessment

Long term exposure estimates over large areas can be made using a combination of air quality models and population density data. However, the grid resolution of such models is often limited to 25–50 km and there may be a significant level of unresolved variability within the grids that will impact on the exposure estimates. In this paper the sub-grid variability is assessed using air quality monitoring (AirBase) and population data, concentrating on the covariance of concentration and population, which is the defining term in estimating sub-grid population exposure. The error that occurs when calculating the urban background exposure is assessed. The assessment shows that the error made in the exposure calculation for all of Europe is small for typical CTM resolutions of 50 km. The error is largest for NO2, where the average European urban background exposure is underestimated by 16%. Particulate matter is also underestimated, but only by 6%. Conversely, estimates of ozone exposure (SOMO35) are overestimated by a factor of 15%.