Filters are made of a variety of materials, including fiberglass, polyester, cotton, and paper. The type of material used affects how effectively the filter can clean the air. Paper is the most common material used for factory production cars. It is a very compacted wood pulp that is joined together to make a strong material, which is then folded into an accordion shape to give more surface area and is joined to a rectangle of foam.
It is cheap and efficient, but dirt will eventually clog in the folds of the material, which will restrict air flow. This means it will need to be replaced every one to two years or between 10,000 and 20,000 miles. Cotton air filters are the first port of call for many people who change their standard filter. They feature layers of cotton gauze sandwiched between an aluminum mesh, which provides a less dense material for air to penetrate than paper.
This should theoretically be less restrictive, allowing more air to enter and increase power. However, any bump in the start is likely to be small; a possible change in induction noise will be the only noticeable change in the driving experience. Cotton air filters can last the life of the car, although they need to be cleaned and re-greased once they are sufficiently dirty. Foam air filters are even less restrictive, using multiple layers of foam with different densities to stop contaminants, plus a wire mesh to help maintain the filter's shape.
The downside is that there are fewer restrictions, which means it won't be as effective a filter. Metal filters are made of stainless steel mesh layers and do not need to be greased. With larger gaps between filter material, a metal filter will be less restrictive than cotton and foam designs. However, once again, with fewer restrictions comes less filtration.
This design will naturally let more dirt through, although the particles are not likely to be large enough to cause problems. The engine or cabin air filter that comes with your car is most likely a paper filter. Since the filter needs to be changed every 12,000 to 30,000 miles, it's made to be as affordable as possible. Woven wood pulp provides good airflow while reducing the amount of dust and debris that can enter the engine and wrinkle construction sites.
Automatic paper filters are relatively inexpensive and are made to be disposed of after each use. Finally, you can find a foam filter or filter wrap in the automotive filter replacement section of your local parts store. This is the least popular type of filter, as foam does not offer the same trapping capacity as paper and can restrict airflow. Foam is also the least environmentally friendly type of element. Air filter material or media is the filter component used in air filters.
The type of air filter material used depends on the application. There are many different types of air filter materials that can be selected; each designed to capture different types of recirculated particles. Charcoal air filters are commonly used in air purifiers, range hoods (along with aluminum screens), bathroom fans, and microwaves. Fiberglass air filters provide better airflow in HVAC units and are suitable for capturing only large particles.
Dust holding capacity is the average weight of dust that an air cleaner can hold when loaded with synthetic dust incrementally under specified test conditions. The first and simplest engine air filters were made of paper, and some still are, but you can also get filters made of premium cotton, synthetic foam, and cotton soaked in oils that trap even more contaminants. Air filters are found in many homes, offices, retail spaces, laboratories, clinics, and hospitals. Therefore, they are commonly used in conjunction with HEPA and electrostatic air filters to improve air quality. Activated carbon air filters are effective in removing gaseous pollutants, fumes, vapors and odors present in the air. Air compressor filters or air filters are installed on condensed overhead lines which are used to remove water, solid particles, oil and other contaminants in a multi-stage filtration process.
Early cars did not have air filters in the engine; automotive pioneers quickly discovered that debris entered the engines damaging performance and shortening life.
