The terms ultra clean coal refers to coal that has been washed and ground into fine particles before being chemically treated to remove unwanted minerals such as sulphur, ash, silicone, and other substances.  The coal is then briquetted and coated with a coal sealant.  Ultra clean coal aims to reduce carbon dioxide emissions during coal-powered energy production.

Ultraviolet radiation (UV) refers to the useful or potentially harmful radiation that is emitted from the sun.  Artificial light sources such as tanning booths, black lights, curing lamps, halogen lights, fluorescent and incandescent lights, and some types of lasers also produce ultraviolet radiation.  Humans absorb UV through the outer dead layers of the epidermis, and over exposure may cause harmful health effects such as sunburn, cataracts, and skin cancer. 

An unconfined aquifer is an aquifer that is open to receive surface water.  It is not under pressure, and its water table surface is free to fluctuate up and down depending on the recharge or discharge rate.

Underfloor heating is a form of indoor climate control where the floor is heated with an electrical or water based heating element in order to heat a room.  The heating element is embedded into the floor during construction, which provides no visible evidence of a heating system (eg. vents, air-conditioning units, etc). Depending on the size and design of a home, along with insulation properties, underfloor heating may provide a low energy alternative to traditional heating methods.

Underground injection is a land disposal method where liquid waste such as water, brine, wastewater or water mixed with chemicals, are injected into porous rock formations, generally at great depths, to reduce environmental contamination or human exposure to pollutants. 

An underground source of drinking water refers to an aquifer that currently supplies human drinking water or supplies any public water system.  The water has total dissolved solids (TDS) content of 10,000 milligrams per liter or less.

An underground storage tank (UST) refers to a tank that is located at least ten percent underground and is designed to store petroleum or other hazardous substances. Underground storage tanks have the potential to leak and contaminate soil and groundwater, which may also be a source of drinking water for humans.

The United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental framework that was established at the Rio Earth Summit in 1992.  This framework aims to limit the impact on the climate from human induced activities, by stabilising greenhouse gas concentrations in the atmosphere to a level that will not damage the atmosphere and cause dangerous climate change.

Upcycling refers to the process of converting waste products and materials into new items that are of a higher quality, as a way to reduce waste and greenhouse gas emissions, and save natural resources.

An upgradeable product is a product that has the ability to increase product performance, usability or characteristics without needing to be replaced with an entire new product.  Upgradable products save natural resources, waste and greenhouse gas emissions.

Uranium is a radioactive element that is a rich source of concentrated energy.  This heavy metal is naturally found in low concentrations in rock, soil and seawater. Approximately one third of the world’s uranium reserves are located in Australia.  Uranium mining in Australia is a highly debated political issue due to environmental, health and cultural concerns.

Urban air pollution refers to poor air quality in densely populated urban areas, particularly developed countries, arising from a variety of sources including vehicle emissions, fuel quality, construction and industrial processes.  The six major pollutants that specifically adversely affect urban air quality include carbon monoxide, sulphur dioxide, nitrogen dioxide, lead, particles and photochemical oxidants (as ozone). 

Urban heat island refers to the higher temperature of urban areas in comparison to regional areas, due to the abundance of streets, sidewalks, parking lots, and buildings which contain materials that retain heat.

Urban planning refers to the process of managing and directing city growth to include housing, industry, roads, transportation networks and the natural environment to ensure orderly development.  Urban planning involves many disciplines such as architecture, engineering, public consultation, research and analysis, and environmental studies.

The term urban runoff refers to storm water from urban areas and adjacent residential or commercial properties, which transport sediments and pollutants of various kinds into the sewer systems and receiving waters following rain. 

Urban sprawl refers to the process of clearing natural habitats or agricultural areas to expand existing low-density residential suburbs or to made way for buildings, roads and other infrastructure.  New developments that are created as a result of urban sprawl generally have a high car dependency and limited access to public transport.  The environmental impacts of urban sprawl include loss of natural space, farmland, wetlands, ecosystems and native wildlife, increased stormwater runoff, and an increase in the heat island effect.

Urbanisation refers to the physical growth of cities and suburbs by the human populations that live in urban areas.  More than half of the world’s population lives in urban areas and this trend is expected to increase as the global population rises.  A major environmental impact of urbanization is the heat island effect, which is caused as a result of increased urban structures and asphalt.  This also affects soil moisture uptake and stormwater runoff. The growing number of people living in urban areas places increases pressure on current infrastructure, transportation networks, sanitation systems, health care, energy consumption and food sources.

Urea in cosmetics is synthetically made from ammonia and carbon dioxide. Urea is used as a preservative and/or moisturizer in skin care products.

Urea can cause dermatitis and has been shown to release formaldehyde, which is a well known carcinogen. 

The United States Department of Agriculture’s (USDA) Organic logo can be found on products that has been produced or manufactured through approved methods. 

Utilizes Idling Capacity is a sustainability standard that an ekko.world trader might claim. 

Collaborative consumption traders utilise the idling capacity (downtime, spare space) of products or services to share with others.

Based in the Netherlands, UTZ Certified promotes sustainable farming and better opportunities for farmers, their families and our planet.