Questions & Answers

How does City Air Cleaning work?

Our City Air Cleaning air cleaning system purifies the air in a modular way over several filter stages and thus helps to achieve compliance with the air quality limit values as quickly and permanently as possible.

  • In the first stage coarse impurities and solids are retained.
  • In the second stage the dust load is cleaned by a highly effective electrostatic precipitator. Here, the fine dusts in the air are separated extremely efficiently by an electrostatic fine dust separator. Electrostatic air filters achieve separation rates of 99.9 % and more in large plants.
  • In the third stage, a special process is used to reduce the germ load and viruses.
  • In the fourth stage, the pre-cleaned air is passed through special activated carbon filters, thus reducing residual pollutants and gaseous substances such as nitrogen oxides.

With the help of integrated measurement data acquisition, each individual air purification system can be monitored and optimised at its current location.


Where is City Air Cleaning already in use?

The technological principle of City Air Cleaning is used on a large scale for road tunnel dedusting in various large cities, e.g. Sydney /Australia, Hong Kong or Madrid, where the air in long road tunnels must be cleaned very effectively from the pollution caused by car traffic. Extensive experience has been gained through many years of operation of these patented systems.


How does City Air Cleaning reduce the amount of nitrogen oxides in the air?

In activated carbon filters, nitrogen oxides accumulate on the surface of the carbon. The longer the residence time of the air flowing through the activated carbon, the more nitrogen oxides are bound. In order to achieve a long residence time, the activated carbon filter was equipped with a comparatively large cross-sectional area and depth.


Where is City Air Cleaning installed?

City Air Cleaning is designed for our cities and reduces the air of pollutants at local hotspots and in critical areas. The system is transportable and can be moved easily and quickly to a new installation site if conditions change.

Wherever there is an increased load of nitrogen dioxide and particulate matter and local measures are necessary, City Air Cleaning contributes to improving air quality and enables compliance with limit values. By reducing pollutants, transit bans can be avoided.


How high-maintenance is City Air Cleaning?

The electrostatic dust collector is automatically rinsed, the rinsing water is recycled. The residual dust container must be emptied at longer intervals.

Due to the upstream cleaning stages, the activated carbon is only exposed to a very low level of pollutants and thus has a very long service life compared to conventional processes.

Maintenance consists primarily of regular checks for vandalism.


How does City Air Cleaning clean fine dust from the air?

Dust and aerosols are electrostatically charged in the two-stage electrostatic dust separator and then deposited on special collecting plates. When the collecting plates are full, they are rinsed with water. The water is then cleaned and is available for further rinsing processes.

Electrostatic precipitators do not have a lower limit for the size of dust particles during precipitation. In contrast to conventional filter fabric, which can only filter out dust particles up to a limited minimum grain size, electrostatic dust collectors remove all fine dust.

Furthermore, electrostatic dust collectors are fluidically open systems and have only a very low pressure loss, which means that only low fan power is required to generate the flow, whereas with fabric filters the air resistance increases with increasing contamination.


How much space does City Air Cleaning need?

The electrostatic dust collector is automatically rinsed, the rinsing water is recycled. The residual dust container must be emptied at longer intervals.

Especially for cities we follow a variable and flexible approach. The cleaning system is installed in a space-saving container that only takes up the floor space of a normal car park. It can therefore be set up wherever the area of a car parking lot is available.


How energy intensive is City Air Cleaning?

An intelligent control and measuring system adapts the air purification to the existing pollutant concentration. This means that the system also uses less energy when the pollutant levels are low. Should the pollutant level rise again, City Air Cleaning automatically adapts to the conditions, thus ensuring maximum energy efficiency.

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