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Aerobiological Engineering is a website about healthy indoor environments, how to design them, how to remediate them, and how to build them. Information and links are provided here to assist engineers, biologists, scientists, researchers, and laypersons in making educated decisions about solving indoor aerobiological problems and controlling airborne diseases.

Circle City


Designing a Sustainable Human Environment with Zero Energy Consumption and Aerobiologically Green Buildings

By Wladyslaw Jan Kowalski, PE, PhD


Circle City is a city planning concept in which efficient mass transportation completely eliminates the need for cars and most roads. Housing is arranged separately from most business and industrial facilities but with convenient access to a variety of safe and efficient transportation options. The template for Circle City consists of a transportation circle or oval inside of which is single unit housing, and outside of which is shopping, agriculture, business, and industry, in roughly that order. Traffic on the circular loop is one way, and it may consist of a sunken road for cars, a light rail system, covered walkways and bicycle paths, all linked to open paths to individual homes. The shape of the loop need not be a circle – it could conform to the natural landscape around a valley, for example. The length of the loop is proportional to the number of residents with a 20 kilometer radius being sufficient for about 200,000 residents. Expansion to a large outer loop can accommodate further expansion.




Circle City is self-sufficient for energy and food. Land is allotted outside the main loop such that agriculture is prioritized to provide the essential food requirements for the full population. Land is allotted inside the loop to residences and in the center to parks, recreation, athletics, and stadiums. In the immediate vicinity of the loop and in the loop are the shops and the apartments, and the main businesses. Just outside the loop are the industries, all strategically placed to minimize commutes and maximize access and efficiency. The subground loop consists of tunnels for services – hot water, electricity, communications, etc., as well as transport.

The light rail system runs clockwise one way and would be visible and accessible from all parts of the city. The train could brake on the uphills and accelerate downhill, much like a roller coaster, if the terrain was hilly. Quiet operation is more important to quality service than speed, and such a system would have such low overall energy consumption.

A sunken and partly covered road for cars can be provided, but the cars would be limited to driving this road only. They would be parked along the sides of the road and anyone would take whatever model was available. Car maintenance is be part of corporate utility maintenance. No head-on collisions, no injured pedestrians, no hidden costs to the city, no insurance needed, no car theft possible, minimal pollution and gas consumption.

A combination of above ground walkways and bicycle paths and all-weather or covered trails are an essential part of efficient mass transportation in Circle City. Every bicycle provided free of charge eliminates energy consumption and improves human health in Circle City. The loop will include solidly built extra-wide, partly covered paths suitable for walking, jogging, bicycling, roller blading, etc. More lightly covered, narrower paths will lead to the loop from each domicile or business.



Residential Housing

Housing extends inside the Circle City loop about 2-4 kilometers, and could be roughly and naturally arranged in a honeycomb or hexagonal matrix or other aesthetic pattern. Single-unit housing is assigned in terms of availability and income and is a life-long entitlement by contract. Apartments should be located close to and outside or on the loop.

Inside the single unit housing loop is a massive park in which nature can left largely undisturbed but lanscaped for lasting and free use. Some entertainment facilities like open air theaters and bandstands could exist within this area, but commercial-type nightlife must be limited to the Mall inside the Loop. The central park would be off-limits to vehicles except for emergency access. The park presents a shortcut for intercity commuters. As corporate property, the park can be videocammed everywhere with live images accessible via network connections in homes and apartments.


Planning and Construction

City planning is essential to the development of economic housing. The city must be designed for people as a priority instead of business and traffic. This is a city for living in. Traffic occurs only in the Loop and the associated Mall. Commuting alternatives include – 1) Walking or biking distance access to all essential services, and 2) Convenient, clean, and quiet, mass transportation. The Circle City concept constrains traffic to the single Loop, and arranges housing and facilities to minimize the time and energy spent traveling and commuting. Circle City is a bikers paradise and a daily pleasure for commuters.

Construction begins with a circular, oval, or naturally shaped single loop road. Initially it may be a normal road for cars and trucks, but as construction progresses the road must be transformed into a fully or partly subground closed loop road for car traffic with a light rail system, and a massive enclosed Mall with interior foot and bicycle traffic.

Light Rail


The power and energy systems in Circle City can be dealt with by designing the entire city to be energy-efficient from the ground up. All utilities will follow central plant and cogen plant design concepts. All hot water, cold water, electricity, and other utilities are supplied by the subground Loop tunnels. Homes will have radiant underfloor heating, and no in-home heating or cooling equipment is necessary. Cost-effective solar energy and energy-recovery systems will be used where appropriate. Cooling will be provided by the cold water system and efficient air distribution. Wind energy and solar energy should be the focal points of electrical self-sufficiency and it is entirely possible that these may provide all of the city’s electrical needs. The city is extremely energy efficient overall by design.

Building construction will be primarily concrete, steel, brick, glass, stone, rammed earth, and other such inflammable and sturdy materials. The use of wood will be minimized and no fire hazards will be created by excessive use of wood. Construction must be millennial, that is, it must be built to last a millennium or more. Millenial Architecture forms the basis for all infrastructure, home construction, and corporate business construction. Circle City is built to last and to be inherited by future generations. Heavy stone, concrete, and earth construction would be necessary to make all homes impervious to tornadoes, hurricanes, floods, earthquakes, etc. None of this is beyond current construction technology – it’s a matter of will. Heavy construction at the housing level translates in heavier construction at the multistory and industrial levels. Since all businesses would operate more or less in steady state conditions, that is, with constant supply and demand from a steadily growing population, the job and business markets would have extreme stability and the energy systems can be sized with reliability and planned with predictablity.



Healthy Housing

New housing needs to be constructed that will provide spacious, comfortable, energy-efficiency units that can withstand tornadoes and storm damage for one hundred years or more. The continuous construction of new homes provides full employment, economic prosperity, and market stability. High-quality housing reduces health and social problems to a minimum and eliminates many unnecessary costs. Homes need to be disease-free to eliminate the problem of epidemics in Circle City. Once proper housing has been provided for every resident (i.e. when a critical mass of construction has been acheived), the level of effort in the housing direction will be reduced to providing only for new residents. The excess labor that develops after critical mass housing is reached can then be devoted to other problems like disease, or expended on further public projects.



Farming forms the only reliable basis for any society, industrial or otherwise, since the laborers, who produce the wealth, must be well-fed. The land outside the loop, and outside the industrial areas, is an open area devoted permanently to agriculture with no traversing roads, limited fencing, and farm housing. Farms can be a mixture of corporate farms (for essentials) and private farms (for specialties and non-essentials). In this geometry a fleet of corporate tractors circle the farmland loop and take care of all the plowing and planting in an efficient manner. All organic sewage is recycled in the farmland and piping must be so arranged to deliver sewage outwards from the Loop. Since as little as two roads might be all that is needed into and out of Circle City, these can be subground, with the roofs covered over with topsoil for farming. Products can be efficiently delivered to food processing factories near the Loop, and main distribution outlets and shops in the Mall. After critical mass construction is reached, construction of greenhouses will become an ongoing enterprise in order to increase yields in proportion to poulation growth.

The Circle City Corporation

In the ideal model, Circle City functions as a profitless corporation once it has reached steady-state growth (beyond critical mass construction). The corporate model is not necessarily the only way to build and run Circle City, but it is one convenient option for which the business and legal apparatus, and precedents already exist – the city could be incorporated and employ all residents via contracts. The purpose of the Corporation is to supply the demand for essentials and thereby provide full employment by directing continuous construction. The Corporation balances the dynamic equations of the economy – the equations of supply and demand in a continually growing environment — and preserves them in a steady state condition. The demand for essentials is universal – everyone requires the essentials. In Circle City the supply equals the demand by design and neither can be manipulated. Individual enterprise supplies the demand, if any, for nonessentials. It is only by balancing the equations of economy that growth can be sustained. This means that all laborers employed by the corporation are also provided with essentials by the corporation, including lifelong housing and health care. Each resident is under a contract to the corporation. Non-corporate residents participate on a credit basis. Since every resident will have a corporate credit card, no cash is required in Circle City.

Alternatives to the corporate structure include Tribal Cooperatives, Religious Cooperatives, privately funded and directed programs, and even government-funded or government-run programs, but in the limit these organizations will of necessity become the same as the corporation, if and only if they succeed.

Phases of Construction

There are basically three major phases in the building of Circle City, excluding the planning phase, and these are the Startup and Infrastructure phase, the Pre-Saturation Growth phase, and the Post-Saturation growth Phase. The primary infrastructure is housing, agriculture, utilities, and transportation. Housing must be durable, comfortable, and worthy of human habitation. The principles of Green Building Design must also be fully applied. All housing is integrated with the energy and water systems such that these utilities are provided in the most energy-efficient manner possible.

The agricultural systems need to grow in concert with the inner city facilities. Sufficient food must be provided so that the workers will have no lack of nutrition or good meals. Since Circle City is self-sufficient, there will be very little traffic that needs to enter.

The Starup Phase can be difficult, but as long as food and housing are continuously provided, construction will proceed on a daily basis, and Continuous Growth can be acheived.

Stadiums and Public Facilities

All facilities are public in Circle City and access is not restricted except as safety requires. Inside the central Loop several sports and performance stadiums will be located. Access will be a simple pleasure, with walkways, bikeways, etc. leading from the Loop where mass transport trains bring those from further away. No traffic, no hazards, no restrictions or discomforts of any sort will be presented to residents and stadium fans.



The health of all residents is a priority in Circle City. It starts with food, housing, and education. Housing must not only be green by design, but must be aerobiologically healthy. There are a variety of ways to achieve aerobiologically clean indoor environments and the best of technology should be applied to ensure that the houses and buildings in Circle City prevent the spread of infectious disease rather than promote it as they do in our existing cities.