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No. 65: Impact of use of mobile non-road machinery on air pollution in Denmark

Helge Rørdam Olesen, Morten Winther, Marlene Schmidt Plejdrup, Jørgen Brandt, Matthias Ketzel & Thomas Ellermann. 2013. Luftforurening fra mobile ikke-vejgående maskiner i byområder. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 39s. - Videnskabelig rapport fra DCE - Nationalt Center for Miljø og Energi nr. 65. http://dce2.au.dk/Pub/SR65.pdf.



The present report describes the results of a project concerning the impact of use of mobile non-road machinery on air pollution in Denmark, in particular within the cities of Copenhagen and Aarhus. Focus has been on the category of machinery classified as "non-road machinery in industry".

The project has been carried out by DCE – Danish Centre of Environment and Energy at Aarhus University.

What is the contribution to air pollution from mobile non-road machinery in the towns of Copenhagen and Aarhus?

The impact from mobile non-road machinery on air quality in the towns of Copenhagen and Aarhus and their surroundings has been assessed on the basis of available data. On a Danish national level this type of machines (disregarding the sectors of agriculture and forest) are responsible for 6 % of the emission of NOX and 3 % of the emission of fine particles (PM2.5).

The current assessment addresses the general level of pollution – it is not an assessment of the very local effect felt by neighbours to construction works. The baseline for the assessment is data from the national Danish emission inventory from mobile non-road machinery. This inventory is based on statistical data on a national level. A key question is how this emission is spatially distributed over the country.

No dataset exists describing where the mobile non-road machinery is used. When performing an assessment of the spatial distribution of the emissions from the mobile non-road machinery – without having access to detailed data – one must assume that emission from mobile non-road machinery can be distributed geographically according to a certain distribution key. The key which is normally used for this purpose in Denmark is based on land use data, and the key is industrial area. The rationale is that a large amount of activities for mobile non-road machinery are associated with activities in industrial areas.

Emission inventories based on such a distribution key can necessarily not be precise, but must be regarded as estimates entailed with some uncertainty.

In the present report estimates are given for the contribution to emissions from mobile non-road machinery for the towns of Copenhagen and Aarhus, based on several possible distribution keys. The estimates are intended to define a range, within which the contribution from mobile non-road machinery lies. Use of industrial area is considered to provide relatively central estimates of the contribution from mobile non-road machinery to the general pollution level in Copenhagen and Aarhus. In order to illustrate the sensitivity of the estimates the consequences of using other possible distribution keys are computed. For two of the alternative distribution keys (extent of areas with low buildings, respectively population density) this is done not only for emissions, but also for concentrations of several air pollution components. These two alternative distribution keys should be regarded as extremes that illustrate the consequences of use of entirely different criteria than now.

A full calculation resulting in concentration estimates at street level at H.C. Andersens Boulevard shows that the computed contribution to NO2 from mobile non-road machinery for 2010 is 0.4 ?g/m3 according to the normal distribution key (industrial area). This value can be regarded as a relatively central estimate. The value can be compared to a total computed level of 48 ?g/m3 locally at street level, and a (computed) urban background level in the area of 20 ?g/m3. When using an alternative distribution key based on population density the contribution is estimated to be a factor of 4 larger – 1.7 ?g/m3 – while it is considerably lower – 0.1 ?g/m3 – when based on the distribution key on the extent of areas with low buildings.

Effect of possible stricter emission standards for mobile non-road machinery

One may imagine many possible forms of stricter environmental regulations, which might be imposed on mobile non-road machinery. Two simple environmental scenarios have been considered in this study. The consequences in terms of national emissions have been computed for the year of 2011.

Scenario 1 is quite radical: It is assumed that all mobile non-road machinery which does not fulfill the newest emission standards is replaced by machinery that does.

Scenario 2 is not so strict: All mobile non-road machinery which do not fulfill the so-called Stage II emission standards (which are not as strict as the newest) are replaced by machines fulfilling the newest standard.

The most drastic scenario (1) results in emission reductions for the entire industrial fleet of mobile non-road machinery of 22% for NOX and 32% for PM2.5 exhaust.

The less drastic scenario (2) results in emission reductions of 14% for NOX and 24 % for PM2.5 exhaust.

An estimate regarding the consequences for concentrations of NO2 shows that for the most restrictive scenario (1), the reduction in NO2 concentration level amounts to approximately 0.1 ?g/m3 on H.C. Andersens Boulevard, assuming that the usual distribution key is pertinent. Such a reduction would be quite modest. The figure is, however, subject to uncertainty due to the uncertainty concerning choice of distribution key.