Clean-Air Technology

A programme to measure the efficiency of techniques to reduce particulate emissions in road sweeping machines

The measurements showed that using lower emission road sweepers can reduce emissions of particulate matter (PM10) in the sweeping process by over 90%. The sweepers also collected over 80% of the test dust and can thus be considered to do their job very efficiently. 

 

Summary

Many municipalities suffer from a high level of fine particulate air pollution. The use of efficient low-emission road sweeping vehicles in inner-city areas could make an effective contribution towards alleviating the problem.

As there is very little data available on the extent to which particulate emissions are reduced in sweeping machines fitted with low-emission filter units or with filter units using other technical dust suppression systems, the project aimed to facilitate comparisons with conventional sweepers using the data collected. 

A variety of low-dust sweeping machines were tested whose main difference lay in their separation systems (exhaust air purification systems such as particulate air filters), their suction systems (wet/dry) and their brush storage (open/closed). These machines were then compared with a reference sweeper not fitted with a dust filtering system.

In order to identify particulate emissions related to the sweeping process (brushes, exhaust air, without emissions generated by the engine and while driving), a measuring method with reproducible test conditions was developed and applied.

Using this measuring method, two sweeping scenarios (kerbstone and road sweeping) were tested on areas of differing widths. A further test was carried out when driving the machines without any sweeping action.

The test focused particularly on identifying the amount of particulate matter (PM10) reduced by using lower-emission sweeping machines, and on assessing their cleaning performance (sweeping efficiency).

 

Findings

Separating efficiency: It was possible to reduce the particles emitted in the exhaust air of the lower-emission dry-sweeping machines by between 99.7% and 99.99% in stationary operation.

Measurement of local emissions in the direct vicinity of the sweeping machine showed clearly that the amount of dust generated by sweeping can be reduced far more effectively by enclosing the side brushes instead of fitting a water spray nozzle unit (wet separation).

Sweepers using filter separators and those based on wet suction generated the lowest area-related particulate emissions. 

Both the lower-emission sweepers with filter separators and the ones fitted with a wet suction system showed reductions in PM10 emissions of over 90% compared to the reference sweeper. 

At the same time, the lower-emission dry-suction sweepers swept up the test dust with an efficiency of 78% to 91%. The wet-suction sweeper had the highest sweeping efficiency at around 94%.

Fugitive emissions (brushes, rollers etc.) were responsible for the majority of overall particulate emissions from low-dust sweepers.

Project Participants

Implementing Institutions

DMT GmbH & Co. KG

More Project Information

Project title: Messprogramm zur Ermittlung des möglichen Beitrags emissionsgeminderter Feinstaubkehrmaschinen an der Einhaltung anspruchsvoller Immissionsgrenzwerte für Staubpartikel

Project number: 20224

Project period: 2010 - 2010

Project region: Germany (North Rhine-Westphalia)

Project contact:

Frau Fischer

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+49 (340) 2103 3067

+49 (340) 2104 3067

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Source: Environmental library of the Federal Environment Agency (UBA)