### device | filter:

Air filter
* Most air filters are disposable, although an electrostatic filter can be cleaned with water
  - have a paper media, though there are also cotton gauze and foam filters
* Some air filters do last longer than others because of their ability to hold more dust.
* are filters
  - part of ventilators
  - very costly , and only purify a small percentage of the air in just a single room
* can also help remove many airborne allergens to keep the home environment clean.
* cause air restrictions.
* is clogged with dust particles.
* remove dirt by trapping particles as air passes through the filter media.
* start out clean and soon are covered with soot and dust.

Biological filter
* Most biological filters are also mechanical filters depending on how they are used.
* contain many bacteria themselves.
* convert toxic ammonia, from fish waste, to non-toxic nitrate.
* help nature eliminate toxins in the water, such as ammonia.

### device | filter:

Carbon filter
* are best at removing bad taste, odor, chlorine, and pesticides
  - for alleviating bad odors or taste from drinking water
  - generally on cold water lines in kitchens or bathrooms to filter drinking water
  - most effective for organic molecules and ineffective for dissolved ions
* are the most common adsorption filter
  - commonly used filter to remove chlorine from the water
* consist of carbon impregnated filter fabric or granulated carbon.
* improve flavor and remove some chemicals.
* remove chlorine, organic chemicals, and tastes and smells
  - the contamination from the air before it is released

Ceramic filter
* are the best way to reduce turbidity in drinking water supplies.
* have a raw pottery appearance.

Charcoal filter
* are able to block the passage of sediment and suspended solids.
* eliminate the UV absorbing gases.
* help control odors.

Clean filter
* are more important for heat pump systems than for conventional systems.
* help maintain clean air and provide a more efficient system.

Coffee filter
* appear to trap cholesterol-raising compounds.
* are filters.

Color filter
* allow the cells to change their RGB basic colors.
* are important for bringing out certain kinds of features and enchanting contrast.

Dichroic filter
* are highly color selective producing brighter, cleaner appearing, saturated color.
* reflect unwanted wavelengths back to the light source.
* remove infrared rays for cool work zone.

Different filter
* are used to select the wavelength of light which the solution absorbs the most.
+ Colorimeter, Different parts, Filters: Laboratory equipment
  * Different filters are used to select the wavelength of light which the solution absorbs the most. This makes the colorimeter more accurate. Solutions are usually placed in glass or plastic cuvettes. The usual wavelengths used are between 400 and 700 nanometers.

Dirty filter
* are a breeding ground for parasites and bacteria.
* cause air conditioners to work harder and use more energy.
* reduce the efficiency of a system and can block air circulation.
* restrict airflow and increase energy use.

Fuel filter
- part of fuel systems
* capture unwanted contaminants from the fuel.
* protect the fuel system of the engine.
* trap dirt before gas reaches the carburetor.

Internet filter
* are software pachages that block users from information available online.
* infringe on our freedom of speech because text and writing are parts of speaking.

Light filter
* are cylindrical sleeves that easily slip over existing fluorescent lamps.
* prevent fading.

Mechanical filter
* can remove only a certain type and size particulates from the air.
* provide protection against particulates such as dusts, mists or metal fumes
  - by trapping particulate matter in the fibrous filter material
* work by physically trapping particulate matter.