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29.04.2024

Not all filters are same – how do you find the right one?

Filters, particularly cabin air filters, have become increasingly important over the last couple of years. This is not only due to the steadily rising number of people with respiratory diseases and allergies but also to the increase in air pollution. Finding the right cabin air filter is no easy task. Having the right materials, the right fit and, last but not least, the appropriate filtering of fine dust and bacteria is key. In this article, we give you some useful tips and tricks on what to look out for when picking a filter.

Different types of filters

Nowadays, the range of different types of filters extends from particle filters to special activated carbon filters. So what are the differences?

Standard particle filters are designed to filter air pollutants in various states and sizes of <5 micrometres. These include pollen, road dust, wear off from brakes, tyres or clutches as well as soot or dust.

In addition to its normal filter function, an activated carbon filter can also bind gases such as ozone, nitrogen or sulphur dioxide. The wide surface area of the activated carbon is what makes this possible.

But not all coal is the same

Did you know that the surface structure of activated carbon depends on its origin?

Coconut fibre, for example, has a rather broad surface structure compared to stone, lignite and charcoal. This is particularly advantageous as it allows a longer contact time with the coal while a higher amount of iodine in mg/g coal, also known as the CTC value, can be absorbed.

💡 A longer contact time also ensures that more organic compounds can be absorbed, allowing the filter to work more effectively.

The right materials make all the difference

However, even the highest quality raw materials are of limited use if the manufacturing process is not carried out properly – since even a small bypass will result in a large proportion of the filter performance being lost. An elastic fleece makes for the ideal material in this case, as it not only ensures that the filter can adjust optimally to the space provided for it in the vehicle, but also that the filter performance remains consistent over time.

Development of filter media

In addition to particle filters and standard activated carbon filters, there are others that filter not only pollen, fine dust and gases, but also nitrogen oxides (NOx). The unique aspect of this is that NOx is not only filtered, but also bound as a chemical salt compound which is not released even when disposed of. This is made possible by an additional layer of specially impregnated activated carbon.

Filter development has progressed rapidly over the past couple of years and will continue to do so in the future. The first HEPA filters, which filter viruses as well as fine dust and bacteria, are already on the market – and the trend is growing.