An urban canyon is an artefact of an urban

Urban area

An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...

 environment similar to a natural canyon

Canyon

A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...

. It is manifested by street

Street

A street is a paved public thoroughfare in a built environment. It is a public parcel of land adjoining buildings in an urban context, on which people may freely assemble, interact, and move about. A street can be as simple as a level patch of dirt, but is more often paved with a hard, durable...

s cutting through dense blocks of structures, especially skyscraper

Skyscraper

A skyscraper is a tall, continuously habitable building of many stories, often designed for office and commercial use. There is no official definition or height above which a building may be classified as a skyscraper...

s, which causes a canyon effect. Examples of urban canyon include the Magnificent Mile

Magnificent Mile

The Magnificent Mile, sometimes referred to as The Mag Mile, is a neighborhood in Chicago, Illinois, that runs along a portion of Michigan Avenue extending from the Chicago River to Oak Street in the Near North Side community area. The district is located adjacent to downtown; it is also one block...

 in Chicago, the Canyon of Heroes in Manhattan, and Hong Kong's Kowloon

Kowloon

Kowloon is an urban area in Hong Kong comprising the Kowloon Peninsula and New Kowloon. It is bordered by the Lei Yue Mun strait in the east, Mei Foo Sun Chuen and Stonecutter's Island in the west, Tate's Cairn and Lion Rock in the north, and Victoria Harbour in the south. It had a population of...

 and Central

Central, Hong Kong

Central is the central business district of Hong Kong. It is located in Central and Western District, on the north shore of Hong Kong Island, across Victoria Harbour from Tsim Sha Tsui, the southernmost point of Kowloon Peninsula...

 districts.
Urban canyons have an impact on various local conditions:

• radio reception
  Radio
  Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
  
  , particularly reception of GPS signals.
• wind speed
  Wind speed
  Wind speed, or wind velocity, is a fundamental atmospheric rate.Wind speed affects weather forecasting, aircraft and maritime operations, construction projects, growth and metabolism rate of many plant species, and countless other implications....
  
  , as moving air is channeled and accelerated
• temperature
  Temperature
  Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
  
  , which can be elevated 5-10 degrees F (2-4 degrees C) and contributes to the urban heat island
  Urban heat island
  An urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas. The phenomenon was first investigated and described by Luke Howard in the 1810s, although he was not the one to name the phenomenon. The temperature difference usually is larger at night...
  
   effect
• air quality
  Air Quality Index
  Air quality is defined as a measure of the condition of air relative to the requirements of one or more biotic species or to any human need or purpose. Air quality indices are numbers used by government agencies to characterize the quality of the air at a given location...
  
  , where locally stagnant air concentrates pollutants near ground level