Dirt is any matter considered unclean, especially when in contact with a person's clothes, skin, or possessions. In such cases, they are said to become dirty. Common types of dirt include: * Debris: scattered pieces of waste or remains *

Dust Dust is made of particle size, fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian processes, aeolian process), Types of volcan ...

: a general powder of organic or mineral matter * Filth: foul matter such as

excrement Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...

* Grime: a black, ingrained dust such as soot *

Soil Soil, also commonly referred to as earth, is a mixture of organic matter, minerals, gases, water, and organisms that together support the life of plants and soil organisms. Some scientific definitions distinguish dirt from ''soil'' by re ...

: the mix of

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

, and

humus In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Lati ...

which lies on top of bedrock. The term 'soil' may be used to refer to unwanted substances or dirt that are deposited onto surfaces such as clothing.

Etymology

The word ''dirt'' first appears in

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman Conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English pe ...

and was probably borrowed from the

Old Norse Old Norse, also referred to as Old Nordic or Old Scandinavian, was a stage of development of North Germanic languages, North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants ...

, meaning .

Exhibitions and studies

A season of artworks and exhibits on the theme of dirt was sponsored by the

Wellcome Trust The Wellcome Trust is a charitable foundation focused on health research based in London, United Kingdom. It was established in 1936 with legacies from the pharmaceutical magnate Henry Wellcome (founder of Burroughs Wellcome, one of the predec ...

in 2011. The centrepiece was an exhibition at the Wellcome Collection showing pictures and histories of notable dirt such as the great dust heaps at Euston and King's Cross in the 19th century and the Fresh Kills landfill which was once the world's largest landfill.

Cleaning

When things are dirty, they are usually cleaned with solutions like hard surface cleaner and other chemical solutions; much domestic activity is for this purpose—washing, sweeping, and so forth. In a commercial setting, a dirty appearance gives a bad impression. An example of such a place is a restaurant. The dirt in such cases may be classified as temporary, permanent, and deliberate. Temporary dirt is streaks and detritus that may be removed by ordinary daily cleaning. Permanent dirt is ingrained stains or physical damage to an object, which requires major renovation to remove. Deliberate dirt is that which results from design decisions such as decor in dirty orange or grunge styling.

Disposal

As cities developed, arrangements were made for the disposal of trash through the use of waste management services. In the United Kingdom, the Public Health Act 1875 required households to place their refuse into a container that could be moved so that it could be carted away. This was the first legal creation of the

dustbin A waste container, also known as a dustbin, rubbish bin, trash can, garbage can, wastepaper basket, and wastebasket, among other names, is a type of container intended to store waste that is usually made out of metal or plastic. The words "r ...

Health

Modern society is now thought to be more hygienic. Lack of contact with

microorganism A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen ...

s in dirt when growing up is hypothesised to be the cause of the epidemic of

allergies Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...

such as

asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...

. The human

immune system The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic ...

requires activation and exercise in order to function properly and exposure to dirt may achieve this. For example, the presence of

staphylococcus ''Staphylococcus'', from Ancient Greek σταφυλή (''staphulḗ''), meaning "bunch of grapes", and (''kókkos''), meaning "kernel" or " Kermes", is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillale ...

bacteria on the surface of the skin regulates the

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

which results from injury. Even when no visible dirt is present, contamination by microorganisms, especially

pathogen In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...

s, can still cause an object or location to be considered dirty. For example,

computer keyboard A computer keyboard is a built-in or peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or Push-button, keys to act as Mechanical keyboard, mechanical levers or Electronic switching system, electro ...

s are especially dirty as they contain on average 70 times more

microbe A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

s than a lavatory seat. People and animals may eat dirt. This is thought to be caused by mineral deficiency and so the condition is commonly seen in pregnant women.

Neurosis

People may become obsessed by dirt and engage in fantasies and compulsive behaviour about it, such as making and consuming mud pies and pastries. The source of such thinking may be genetic, as the emotion of

disgust Disgust (, from Latin , ) is an emotional response of rejection or revulsion to something potentially contagious or something considered offensive, distasteful or unpleasant. In ''The Expression of the Emotions in Man and Animals'', Charles D ...

is common and the location for this activity in the brain has been proposed.

References

External links

*
Dirt season at the Wellcome Collection
{{Authority control Hygiene Waste