Greater St. Louis
Greater St. Louis is a bi-state metropolitan area that surrounds and includes the independent city of St. Louis, it includes parts of both the U. S. states of Illinois. The city core is on the Mississippi Riverfront on the border with Illinois in the geographic center of the metro area; the Mississippi River bisects the metro area in half geographically between Missouri. St. Louis is the second largest in Illinois. St. Louis County is independent of the City of St. Louis and their two populations are tabulated separately; the St. Louis, MO-IL metropolitan statistical area —and the focus of this page—includes the City of St. Louis; the larger St. Louis–St. Charles–Farmington, MO–IL combined statistical area includes all of the aforementioned MSA, plus the Farmington, MO micropolitan statistical area, which includes all of St. Francois County and the Centralia, IL micropolitan statistical area, which includes Marion County, Illinois; as of 2017 data, the MSA is the 21st-largest in the country that year with a population of 2,807,338.
Due to nearly zero growth in St. Louis paired with rapid growth in the Sun Belt and Florida, the St. Louis MSA fell out of the Top 20 Largest MSAs in the United States in 2017 for the first time since 1840; as of 2018, Greater St. Louis is home to the headquarters of ten of Missouri's eleven Fortune 500 companies, six Fortune 1,000 companies, two of the top 30 Largest Private Companies in America, as ranked by Forbes; the area received the All-America City Award in 2008. The history of St. Louis, Missouri began with the settlement of the St. Louis area by Native American mound builders who lived as part of the Mississippian culture from the 9th century to the 15th century, followed by other migrating tribal groups. Starting in the late 17th century, French explorers arrived. Spain took over in 1763 and a trading company established the settlement of St. Louis in February 1764; the city became part of the U. S. through the Louisiana Purchase in 1803. The American Civil War saw St. Louis had a small skirmish on its outskirts, but was held under Union control.
After the war, the city expanded industrial activity. Franklin County MO: Berger, New Haven, Pacific, St. Clair, Union, Washington Jefferson County MO: Arnold, Byrnes Mill, Crystal City, De Soto, Herculaneum, Imperial, Pevely Lincoln County MO: Elsberry, Moscow Mills, Old Monroe, Winfield St. Francois County MO: Bonne Terre, Farmington, Park Hills St. Charles County MO: Cottleville, Dardenne Prairie, Foristell, Lake St. Louis, New Melle, O'Fallon, St. Charles, St. Peters, Weldon Spring, West Alton St. Louis: City of St. Louis St. Louis County MO: Affton, Bel-Nor, Bel-Ridge, Bella Villa, Bellefontaine Neighbors, Berkeley, Beverly Hills, Black Jack, Breckenridge Hills, Bridgeton, Calverton Park, Charlack, Clarkson Valley, Cool Valley, Country Club Hills, Country Life Acres, Creve Coeur, Crystal Lake Park, Des Peres, Ellisville, Fenton, Flordell Hills, Frontenac, Glen Echo Park, Grantwood Village, Green Park, Hanley Hills, Hillsdale, Kinloch, Jennings, Lakeshire, Maplewood, Maryland Heights, Moline Acres, Northwoods, Norwood Court, Olivette, Pacific, Pasadena Hills, Pasadena Park, Pine Lawn, Richmond Heights, Rock Hill, St. Ann, St. John, Spanish Lake, Sunset Hills, Sycamore Hills, Town & Country, Twin Oaks, University City, Uplands Park, Valley Park, Velda City, Velda Village Hills, Vinita Park, Warson Woods, Webster Groves, Westwood, Wilbur Park, Winchester, Woodson Terrace Warren County MO: Foristell, Truesdale, Wright City Bond County IL: Greenville, Sorento Calhoun County IL: Brussels, Kampsville Clinton County IL: Aviston, Breese, Centralia, New Baden, Trenton Jersey County IL: Grafton, Jerseyville Macoupin County IL: Benld, Bunker Hill, Gillespie, Mt. Olive, Virden Madison County IL: Alhambra, Bethalto, East Alton, Godfrey, Glen Carbon, Granite City, Hartford, Livingston, Marine, New Douglas, Pontoon Beach, South Roxana, St. Jacob, Venice, Wood River, Worden Monroe County IL: Columbia, Valmeyer, Waterloo St. Clair County IL: Alorton, Brooklyn, Caseyville, Dupo, East Carondelet, East St. Louis, Fairmont City, Fairview Heights, Freeburg, Marissa, Millstadt, New Athens, O'Fallon, Shiloh, Smithton, St. Libory, Washington ParkAs noted above, the Greater St. Louis area includes two cities named O'Fallon and two cities named Troy.
The nearby Hannibal–Quincy micropolitan areas are technically not located within the metropolitan, but are regionally associated due to their proximity and accessibility to Gr
A city council, town council, town board, or board of aldermen is the legislative body that governs a city, municipality, or local government area. Because of the differences in legislation between the states, the exact definition of a City Council varies. However, it is only those local government areas which have been granted city status that are entitled to refer to themselves as cities; the official title is "Corporation of the City of ______" or similar. Some of the urban areas of Australia are governed by a single entity, while others may be controlled by a multitude of much smaller city councils; some significant urban areas can be under the jurisdiction of otherwise rural local governments. Periodic re-alignments of boundaries attempt to rationalize these situations and adjust the deployment of assets and resources; the 2001 Local Government Act restyled the five county boroughs of Dublin, Galway and Limerick as city councils, with the same status in law as county councils. The 2014 Local Government Act Merged Limerick City and Limerick County Council together and Waterford City and Waterford County Council together abolishing Waterford and Limerick City council, While Limerick and Waterford maintain City Status.
The city councils and city halls in Malaysia are as follows. Alor Setar City Council Ipoh City Council Iskandar Puteri City Council Johor Bahru City Council Kota Kinabalu City Hall Kuala Lumpur City Hall Kuala Terengganu City Council Kuching North City Hall Kuching South City Council Melaka City Council Miri City Council Penang Island City Council Petaling Jaya City Council Shah Alam City Council Local councils in New Zealand do vary in structure, but are overseen by the government department Local Government New Zealand. For many decades until the local government reforms of 1989, a borough with more than 20,000 people could be proclaimed a city; the boundaries of councils tended to follow the edge of the built-up area, so little distinction was made between the urban area and the local government area. New Zealand's local government structural arrangements were reformed by the Local Government Commission in 1989 when 700 councils and special purpose bodies were amalgamated to create 87 new local authorities.
As a result, the term "city" began to take on two meanings. The word "city" came to be used in a less formal sense to describe major urban areas independent of local body boundaries; this informal usage is jealously guarded. Gisborne, for example, adamantly described itself as the first city in the world to see the new millennium. Gisborne is administered by a district council, but its status as a city is not disputed. Under the current law the minimum population for a new city is 50,000. In the Republic of China, a city council represents a provincial city. Members of the councils are elected through local elections for provincial cities which are held every 4–5 years. Councils for the provincial cities in Taiwan are Chiayi City Council, Hsinchu City Council, Keelung City Council. In the UK, not all cities have city councils, the status and functions of city councils vary. A city council may be: The council of a metropolitan district, granted city status; the council of a non-metropolitan district, granted city status.
Some of these councils are some share functions with county councils. A parish council, granted city status; these councils have limited functions. The council of a London borough, granted city status, or the City of London Corporation. A city council may be: One of the three councils of principal areas that have been granted city status. One of the three community councils, with limited functions, that have been granted city status. A city council is the council of one of four council areas designated a City by the Local Government etc. Act 1994; the three cities which are not council areas have no city council. Belfast City Council is now the only city council. Since the local government reforms of 2015 the other four cities form parts of wider districts and do not have their own councils. City councils and town boards consist of several elected aldermen or councillors. In the United States, members of city councils are called council member, council man, council woman, councilman, or councilwoman, while in Canada they are called councillor.
In some cities, the mayor is a voting member of the council. In larger cities the council may elect other executive positions as well, such as a council president and speaker; the council functions as a parliamentary or congressional style legislative body, proposing bills, holding votes, passing laws to help govern the city. The role of the mayor in the council varies depending on whether or not the city uses council–manager government or mayor–council government, by the nature of the statutory authority given to it by state law, city charter, or municipal ordinance. There is a mayor pro tem councilmember. In cities where the council elects the mayor for one year at a time, the mayor pro tem is in line to become the mayor in the next year. In cities where the mayor is elected by the city's voters, the mayor pro tem serves as acting mayor in the absence of the mayor; this position is known as vice mayor. In some cities a different name for the municipal legislature is used. In San
St. Louis is an independent city and major inland port in the U. S. state of Missouri. It is situated along the western bank of the Mississippi River, which marks Missouri's border with Illinois; the Missouri River merges with the Mississippi River just north of the city. These two rivers combined form the fourth longest river system in the world; the city had an estimated 2017 population of 308,626 and is the cultural and economic center of the St. Louis metropolitan area, the largest metropolitan area in Missouri, the second-largest in Illinois, the 22nd-largest in the United States. Before European settlement, the area was a regional center of Native American Mississippian culture; the city of St. Louis was founded in 1764 by French fur traders Pierre Laclède and Auguste Chouteau, named after Louis IX of France. In 1764, following France's defeat in the Seven Years' War, the area was ceded to Spain and retroceded back to France in 1800. In 1803, the United States acquired the territory as part of the Louisiana Purchase.
During the 19th century, St. Louis became a major port on the Mississippi River, it separated from St. Louis County in 1877, becoming an independent city and limiting its own political boundaries. In 1904, it hosted the Summer Olympics; the economy of metropolitan St. Louis relies on service, trade, transportation of goods, tourism, its metro area is home to major corporations, including Anheuser-Busch, Express Scripts, Boeing Defense, Energizer, Enterprise, Peabody Energy, Post Holdings, Edward Jones, Go Jet and Sigma-Aldrich. Nine of the ten Fortune 500 companies based in Missouri are located within the St. Louis metropolitan area; this city has become known for its growing medical and research presence due to institutions such as Washington University in St. Louis and Barnes-Jewish Hospital. St. Louis has two professional sports teams: the St. Louis Cardinals of Major League Baseball and the St. Louis Blues of the National Hockey League. One of the city's iconic sights is the 630-foot tall Gateway Arch in the downtown area.
The area that would become St. Louis was a center of the Native American Mississippian culture, which built numerous temple and residential earthwork mounds on both sides of the Mississippi River, their major regional center was at Cahokia Mounds, active from 900 to 1500. Due to numerous major earthworks within St. Louis boundaries, the city was nicknamed as the "Mound City"; these mounds were demolished during the city's development. Historic Native American tribes in the area included the Siouan-speaking Osage people, whose territory extended west, the Illiniwek. European exploration of the area was first recorded in 1673, when French explorers Louis Jolliet and Jacques Marquette traveled through the Mississippi River valley. Five years La Salle claimed the region for France as part of La Louisiane; the earliest European settlements in the area were built in Illinois Country on the east side of the Mississippi River during the 1690s and early 1700s at Cahokia and Fort de Chartres. Migrants from the French villages on the opposite side of the Mississippi River founded Ste.
Genevieve in the 1730s. In early 1764, after France lost the 7 Years' War, Pierre Laclède and his stepson Auguste Chouteau founded what was to become the city of St. Louis; the early French families built the city's economy on the fur trade with the Osage, as well as with more distant tribes along the Missouri River. The Chouteau brothers gained a monopoly from Spain on the fur trade with Santa Fe. French colonists used African slaves as domestic workers in the city. France, alarmed that Britain would demand French possessions west of the Mississippi and the Missouri River basin after the losing New France to them in 1759–60, transferred these to Spain as part of the Viceroyalty of New Spain; these areas remained in Spanish possession until 1803. In 1780 during the American Revolutionary War, St. Louis was attacked by British forces Native American allies, in the Battle of St. Louis; the founding of St. Louis began in 1763. Pierre Laclede led an expedition to set up a fur-trading post farther up the Mississippi River.
Before Laclede had been a successful merchant. For this reason, he and his trading partner Gilbert Antoine de St. Maxent were offered monopolies for six years of the fur trading in that area. Although they were only granted rights to set-up a trading post and other members of his expedition set up a settlement; some historians believe that Laclede's determination to create this settlement was the result of his affair with a married woman Marie-Thérèse Bourgeois Chouteau in New Orleans. Laclede on his initial expedition was accompanied by Auguste Chouteau; some historians still debate. The reason for this lingering question is that all the documentation of the founding was loaned and subsequently destroyed in a fire. For the first few years of St. Louis's existence, the city was not recognized by any of the governments. Although thought to be under the control of the Spanish government, no one asserted any authority over the settlement, thus St. Louis had no local government; this led Laclede to assume a position of civil control, all problems were disposed i
A city is a large human settlement. Cities have extensive systems for housing, sanitation, land use, communication, their density facilitates interaction between people, government organizations and businesses, sometimes benefiting different parties in the process. City-dwellers have been a small proportion of humanity overall, but following two centuries of unprecedented and rapid urbanization half of the world population now lives in cities, which has had profound consequences for global sustainability. Present-day cities form the core of larger metropolitan areas and urban areas—creating numerous commuters traveling towards city centers for employment and edification. However, in a world of intensifying globalization, all cities are in different degree connected globally beyond these regions; the most populated city proper is Chongqing while the most populous metropolitan areas are the Greater Tokyo Area, the Shanghai area, Jabodetabek. The cities of Faiyum and Varanasi are among those laying claim to longest continual inhabitation.
A city is distinguished from other human settlements by its great size, but by its functions and its special symbolic status, which may be conferred by a central authority. The term can refer either to the physical streets and buildings of the city or to the collection of people who dwell there, can be used in a general sense to mean urban rather than rural territory. A variety of definitions, invoking population, population density, number of dwellings, economic function, infrastructure, are used in national censuses to classify populations as urban. Common population definitions for a city range between 1,500 and 50,000 people, with most U. S. states using a minimum between 5,000 inhabitants. However, some jurisdictions set no such minimums. In the United Kingdom, city status is awarded by the government and remains permanently, resulting in some small cities, such as Wells and St Davids. According to the "functional definition" a city is not distinguished by size alone, but by the role it plays within a larger political context.
Cities serve as administrative, commercial and cultural hubs for their larger surrounding areas. Examples of settlements called city which may not meet any of the traditional criteria to be named such include Broad Top City and City Dulas, Anglesey, a hamlet; the presence of a literate elite is sometimes included in the definition. A typical city has professional administrators and some form of taxation to support the government workers; the governments may be based on heredity, military power, work projects such as canal building, food distribution, land ownership, commerce, finance, or a combination of these. Societies that live in cities are called civilizations; the word city and the related civilization come, via Old French, from the Latin root civitas meaning citizenship or community member and coming to correspond with urbs, meaning city in a more physical sense. The Roman civitas was linked with the Greek "polis"—another common root appearing in English words such as metropolis. Urban geography deals both with their internal structure.
Town siting has varied through history according to natural, technological and military contexts. Access to water has long been a major factor in city placement and growth, despite exceptions enabled by the advent of rail transport in the nineteenth century, through the present most of the world's urban population lives near the coast or on a river. Urban areas as a rule cannot produce their own food and therefore must develop some relationship with a hinterland which sustains them. Only in special cases such as mining towns which play a vital role in long-distance trade, are cities disconnected from the countryside which feeds them. Thus, centrality within a productive region influences siting, as economic forces would in theory favor the creation of market places in optimal mutually reachable locations; the vast majority of cities have a central area containing buildings with special economic and religious significance. Archaeologists refer to this area by the Greek term temenos; these spaces reflect and amplify the city's centrality and importance to its wider sphere of influence.
Today cities have downtown, sometimes coincident with a central business district. Cities have public spaces where anyone can go; these include owned spaces open to the public as well as forms of public land such as public domain and the commons. Western philosophy since the time of the Greek agora has considered physical public space as the substrate of the symbolic public sphere. Public art adorns public spaces. Parks and other natural sites within cities provide residents with relief from the hardness and regularity of typical built environments. Urban structure follows one or more basic patterns: geomorphic, concentric and curvilinear. Physical environment constrains the form in which a city is built. If located on a mountainside, urban structure may rely on winding roads, it may be adapted to its means of subsistence. And it may be set up for optimal defense given the surrounding landscape. Beyond these "geomorphi
A ZIP Code is a postal code used by the United States Postal Service in a system it introduced in 1963. The term ZIP is an acronym for Zone Improvement Plan; the basic format consists of five digits. An extended ZIP+4 code was introduced in 1983 which includes the five digits of the ZIP Code, followed by a hyphen and four additional digits that reference a more specific location; the term ZIP Code was registered as a servicemark by the U. S. Postal Service, but its registration has since expired; the early history and context of postal codes began with postal district/zone numbers. The United States Post Office Department implemented postal zones for numerous large cities in 1943. For example: The "16" was the number of the postal zone in the specific city. By the early 1960s, a more organized system was needed, non-mandatory five-digit ZIP Codes were introduced nationwide on July 1, 1963; the USPOD issued its Publication 59: Abbreviations for Use with ZIP Code on October 1, 1963, with the list of two-letter state abbreviations which are written with both letters capitalized.
An earlier list in June had proposed capitalized abbreviations ranging from two to five letters. According to Publication 59, the two-letter standard was "based on a maximum 23-position line, because this has been found to be the most universally acceptable line capacity basis for major addressing systems", which would be exceeded by a long city name combined with a multi-letter state abbreviation, such as "Sacramento, Calif." along with the ZIP Code. The abbreviations have remained unchanged, with the exception of Nebraska, changed from NB to NE in 1969 at the request of the Canadian postal administration, to avoid confusion with the Canadian province of New Brunswick. Robert Moon is considered the father of the ZIP Code; the post office only credits Moon with the first three digits of the ZIP Code, which describe the sectional center facility or "sec center." An SCF is a central mail processing facility with those three digits. The fourth and fifth digits, which give a more precise locale within the SCF, were proposed by Henry Bentley Hahn Sr.
The SCF sorts mail to all post offices with those first three digits in their ZIP Codes. The mail is sorted according to the final two digits of the ZIP Code and sent to the corresponding post offices in the early morning. Sectional centers do not deliver mail and are not open to the public, most of their employees work the night shift. Mail picked up at post offices is sent to their own SCF in the afternoon, where the mail is sorted overnight. In the case of large cities, the last two digits coincide with the older postal zone number thus: In 1967, these became mandatory for second- and third-class bulk mailers, the system was soon adopted generally; the United States Post Office used a cartoon character, which it called Mr. ZIP, to promote the use of the ZIP Code, he was depicted with a legend such as "USE ZIP CODE" in the selvage of panes of postage stamps or on the covers of booklet panes of stamps. In 1971 Elmira Star-Gazette reporter Dick Baumbach found out the White House was not using a ZIP Code on its envelopes.
Herb Klein, special assistant to President Nixon, responded by saying the next printing of envelopes would include the ZIP Code. In 1983, the U. S. Postal Service introduced an expanded ZIP Code system that it called ZIP+4 called "plus-four codes", "add-on codes", or "add-ons". A ZIP+4 Code uses the basic five-digit code plus four additional digits to identify a geographic segment within the five-digit delivery area, such as a city block, a group of apartments, an individual high-volume receiver of mail, a post office box, or any other unit that could use an extra identifier to aid in efficient mail sorting and delivery. However, initial attempts to promote universal use of the new format met with public resistance and today the plus-four code is not required. In general, mail is read by a multiline optical character reader that instantly determines the correct ZIP+4 Code from the address—along with the more specific delivery point—and sprays an Intelligent Mail barcode on the face of the mail piece that corresponds to 11 digits—nine for the ZIP+4 Code and two for the delivery point.
For Post Office Boxes, the general rule is. The add-on code is one of the following: the last four digits of the box number, zero plus the last three digits of the box number, or, if the box number consists of fewer than four digits, enough zeros are attached to the front of the box number to produce a four-digit number. However, there is no uniform rule, so the ZIP+4 Code must be looked up individually for each box; the ZIP Code is translated into an Intelligent Mail barcode, printed on the mailpiece to make it easier for automated machines to sort. A barcode can be printed by the sender, it is better to let the post office put one on. In general, the post office uses OCR technology, though in some cases a human might have to read and enter the address. Customers who send bulk mail can get a discount on postage if they have printed the barcode themselves and have presorted the mai
Race and ethnicity in the United States Census
Race and ethnicity in the United States Census, defined by the federal Office of Management and Budget and the United States Census Bureau, are self-identification data items in which residents choose the race or races with which they most identify, indicate whether or not they are of Hispanic or Latino origin. The racial categories represent a social-political construct for the race or races that respondents consider themselves to be and, "generally reflect a social definition of race recognized in this country." OMB defines the concept of race as outlined for the US Census as not "scientific or anthropological" and takes into account "social and cultural characteristics as well as ancestry", using "appropriate scientific methodologies" that are not "primarily biological or genetic in reference." The race categories include both national-origin groups. Race and ethnicity are considered separate and distinct identities, with Hispanic or Latino origin asked as a separate question. Thus, in addition to their race or races, all respondents are categorized by membership in one of two ethnic categories, which are "Hispanic or Latino" and "Not Hispanic or Latino".
However, the practice of separating "race" and "ethnicity" as different categories has been criticized both by the American Anthropological Association and members of US Commission on Civil Rights. In 1997, OMB issued a Federal Register notice regarding revisions to the standards for the classification of federal data on race and ethnicity. OMB developed race and ethnic standards in order to provide "consistent data on race and ethnicity throughout the Federal Government; the development of the data standards stem in large measure from new responsibilities to enforce civil rights laws." Among the changes, OMB issued the instruction to "mark one or more races" after noting evidence of increasing numbers of interracial children and wanting to capture the diversity in a measurable way and having received requests by people who wanted to be able to acknowledge their or their children's full ancestry rather than identifying with only one group. Prior to this decision, the Census and other government data collections asked people to report only one race.
The OMB states, "many federal programs are put into effect based on the race data obtained from the decennial census. Race data are critical for the basic research behind many policy decisions. States require these data to meet legislative redistricting requirements; the data are needed to monitor compliance with the Voting Rights Act by local jurisdictions". "Data on ethnic groups are important for putting into effect a number of federal statutes. Data on Ethnic Groups are needed by local governments to run programs and meet legislative requirements." The 1790 United States Census was the first census in the history of the United States. The population of the United States was recorded as 3,929,214 as of Census Day, August 2, 1790, as mandated by Article I, Section 2 of the United States Constitution and applicable laws."The law required that every household be visited, that completed census schedules be posted in'two of the most public places within, there to remain for the inspection of all concerned...' and that'the aggregate amount of each description of persons' for every district be transmitted to the president."
This law along with U. S. marshals were responsible for governing the census. One third of the original census data has been lost or destroyed since documentation; the data was lost in 1790–1830 time period and included data from: Connecticut, Maryland, New Hampshire, New York, North Carolina, Rhode Island, South Carolina, Delaware, New Jersey, Virginia. Census data included the name of the head of the family and categorized inhabitants as follows: free white males at least 16 years of age, free white males under 16 years of age, free white females, all other free persons, slaves. Thomas Jefferson the Secretary of State, directed marshals to collect data from all thirteen states, from the Southwest Territory; the census was not conducted in Vermont until 1791, after that state's admission to the Union as the 14th state on March 4 of that year. There was some doubt surrounding the numbers, President George Washington and Thomas Jefferson maintained the population was undercounted; the potential reasons Washington and Jefferson may have thought this could be refusal to participate, poor public transportation and roads, spread out population, restraints of current technology.
No microdata from the 1790 population census is available, but aggregate data for small areas and their compatible cartographic boundary files, can be downloaded from the National Historical Geographic Information System. In 1800 and 1810, the age question regarding free white males was more detailed; the 1820
Relative humidity is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature. Relative humidity depends on the pressure of the system of interest; the same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is that of dewpoint; the relative humidity of an air–water mixture is defined as the ratio of the partial pressure of water vapor in the mixture to the equilibrium vapor pressure of water over a flat surface of pure water at a given temperature: ϕ = p H 2 O p H 2 O ∗. Relative humidity is expressed as a percentage. At 100 % relative humidity, the air is at its dewpoint. Climate control refers to the control of temperature and relative humidity in buildings and other enclosed spaces for the purpose of providing for human comfort and safety, of meeting environmental requirements of machines, sensitive materials and technical processes. Along with air temperature, mean radiant temperature, air speed, metabolic rate, clothing level, relative humidity plays a role in human thermal comfort.
According to ASHRAE Standard 55-2017: Thermal Environmental Conditions for Human Occupancy, indoor thermal comfort can be achieved through the PMV method with relative humidities ranging from 0% to 100%, depending on the levels of the other factors contributing to thermal comfort. However, the recommended range of indoor relative humidity in air conditioned buildings is 30-60%. In general, higher temperatures will require lower relative humidities to achieve thermal comfort compared to lower temperatures, with all other factors held constant. For example, with clothing level = 1, Metabolic rate = 1.1, air speed 0.1 m/s, a change in air temperature and mean radiant temperature from 20 degrees C to 24 degrees C would lower the maximum acceptable relative humidity from 100% to 65% to maintain thermal comfort conditions. The CBE Thermal Comfort Tool can be used to demonstrate the effect of relative humidity for specific thermal comfort conditions and it can be used to demonstrate compliance with ASHRAE Standard 55-2017.
When using the adaptive model to predict thermal comfort indoors, relative humidity is not taken into account. Although relative humidity is an important factor for thermal comfort, humans are more sensitive to variations in temperature than they are to changes in relative humidity. Relative humidity has a small effect on thermal comfort outdoors when air temperatures are low, a more pronounced effect at moderate air temperatures, a much stronger influence at higher air temperatures. In cold climates, the outdoor temperature causes lower capacity for water vapor to flow about, thus although it may be snowing and the relative humidity outdoors is high, once that air comes into a building and heats up, its new relative humidity is low, making the air dry, which can cause discomfort. Dry cracked. Low humidity causes tissue lining nasal passages to dry and become more susceptible to penetration of Rhinovirus cold viruses. Low humidity is a common cause of nosebleeds; the use of a humidifier in homes bedrooms, can help with these symptoms.
Indoor relative humidities should be kept above 30% to reduce the likelihood of the occupant's nasal passages drying out. Humans can be comfortable within a wide range of humidities depending on the temperature—from 30% to 70%—but ideally between 50% and 60%. Low humidity can create discomfort, respiratory problems, aggravate allergies in some individuals. In the winter, it is advisable to maintain relative humidity above. Low relative humidities may cause eye irritation. For climate control in buildings using HVAC systems, the key is to maintain the relative humidity at a comfortable range—low enough to be comfortable but high enough to avoid problems associated with dry air; when the temperature is high and the relative humidity is low, evaporation of water is rapid. Wooden furniture can shrink; when the temperature is low and the relative humidity is high, evaporation of water is slow. When relative humidity approaches 100 percent, condensation can occur on surfaces, leading to problems with mold, corrosion and other moisture-related deterioration.
Condensation can pose a safety risk as it can promote the growth of mold and wood rot as well as freezing emergency exits shut. Certain production and technical processes and treatments in factories, laboratories and other facilities require specific relative humidity levels to be maintained using humidifiers and associated control systems; the basic principles for buildings, above apply to vehicles. In addition, there may be safety considerations. For instance, high humidity inside a vehicle can lead to problems of condensation, such