How do Cabin filters effectively filter harmful substances such as pollen and dust from the air outside the car?

The Cabin Filter is part of the car air conditioning system. It mainly filters the air entering the car and removes harmful substances in it, ensuring that the owner and passengers breathe relatively clean air during driving. Its working principle and effectiveness depend on the material, structure and sealing of the filter element. The following is the principle and method of how the car air filter effectively filters harmful substances (such as pollen, dust, etc.) in the air outside the car:

Filtering principle and material
Car air filters usually use a multi-layer structure and different materials for air filtration. The main filter layers and materials include:
Non-woven fabric (Synthetic Fiber)
This is a commonly used filter element material composed of synthetic fibers with good filtration performance. Through tiny fiber gaps, it can effectively capture larger particles in the air, such as dust, sand, etc.
Activated carbon (Activated Carbon)
Activated carbon is often used in high-end car air filters. In addition to filtering dust and pollen, it can also absorb harmful gases and odors in the air, such as smoke, carbon monoxide, ozone, etc. The surface of activated carbon has a large specific surface area, which can adsorb and lock these harmful substances.
HEPA (High-Efficiency Particulate Air)
HEPA filters are one of the most common high-efficiency air filtration technologies, and are designed to filter out at least 99.97% of particles with a diameter of 0.3 microns or larger. Tiny particles such as pollen, dust mites, bacteria, and viruses can be effectively blocked by HEPA filters, so HEPA filters can provide extremely efficient air purification effects.
Electrostatic Filters
Some high-end car air filters use electrostatic technology to enhance the filtration effect. The electrostatic layer attracts tiny particles in the air and firmly attaches them to the surface of the filter paper, thereby improving the filter's particle capture ability, especially for fine particles such as pollen and dust.
Pollen Filtration
Pollen is an allergy source faced by many people in the spring and autumn seasons, especially in urban environments with heavy air pollution. How the car air filter filters pollen depends mainly on the following aspects:
Filter aperture
The aperture size of the car air filter is the key to whether it can effectively filter pollen. Pollen particles are usually between 10 microns and 100 microns in diameter, and ordinary paper filters can capture these larger particles.
Application of HEPA technology
Car air filters using HEPA filters can filter tiny particles such as pollen in the air more efficiently. HEPA filters can accurately filter pollen in the air and prevent them from entering the car.
Multi-layer filter design

Car air filters are usually designed with a multi-layer filter structure, and each layer filters particles of different sizes. The first few layers usually filter larger particles (such as dust and larger pollen particles), and the subsequent layers use finer filter materials to filter smaller particles such as pollen.
Filtering of dust and pollutants
Dust, sand, smoke, etc. in the air outside the car are common pollutants. These particles are often large, and the car air filter can effectively filter them in the following ways:
Coarser filter structure
For larger particles, such as dust and sand, the car air filter usually uses a coarser filter structure. These larger particles will be directly intercepted on the surface of the filter to prevent them from entering the car.
Multi-layer composite materials
Modern car air filters usually use composite material technology to combine multiple filter layers of different materials to enhance the filtering effect. For example, the front layer uses a coarser filter paper to intercept larger particles, and the back layer uses a finer material to capture tiny particles.
Electrostatic adsorption
Electrostatic technology is also used in car air filters, which can adsorb small particles (such as dust) in the air. This technology can effectively capture fine dust particles in the air and prevent them from entering the car.

The filtering effect of the car air filter depends not only on its initial performance, but also on its long-term use status. In order to maintain effectiveness, the vehicle air filter needs to have the following characteristics:
Good sealing
The vehicle air filter needs good sealing to ensure that the dirty air from the outside does not directly enter the car through the gap of the filter element. A filter with poor sealing may cause some air to enter the car directly without being processed by the filter, reducing the filtering effect.
Durability and long-lasting filtering ability
High-quality air filters can maintain good filtering performance for a long time and are not easy to fail due to long-term use. Usually the service life of the vehicle air filter is 10,000 to 20,000 kilometers, and the specific replacement cycle depends on the use environment and air quality.
Regular replacement
The filtering effect of the vehicle air filter will gradually decrease with the extension of the use time, especially in areas with a lot of dust and serious air pollution, the filter needs to be replaced regularly. Generally speaking, the air filter needs to be replaced every 12,000 to 15,000 kilometers, but if the owner often drives in areas with a lot of pollen and dust, it is recommended to replace it in advance.

The vehicle air filter effectively filters pollen, dust and harmful gases in the air outside the vehicle through fine filter mesh structure, high-efficiency filter materials (such as HEPA, activated carbon, etc.) and electrostatic adsorption, ensuring the health and comfort of the owner and passengers. This also emphasizes the importance of regular inspection and replacement of air filters to maintain the best air quality.