At laboratorial scale, experiments are conducted inside artificially acclimatized architectures. Environmental machines like chemical-chambers or wind-tunnels provide a detached and controllable air-space, making effectively possible, albeit at reduced scale, to conceptualize a formal design of the atmosphere. Models are not much an abstraction of the real but artificial constructions that, despite being limited, enable certain elaboration of a given problem in reality. Inside a wind-tunnel, not all variables are totally incorporated, but the ones integrated into the atmospheric model are fully reproducible and can be precisely modulated. Therefore, the ecological indeterminacy is partially assimilated as a controllable, observable and calculable element inside the system. At real scale, being it an accident in a nuclear power plant, a bio-chemical attack, or a scientific experiment, each event is singular. When realized under controllable atmospheric conditions, however, the rehearsal ad infinitum of the event at accelerated rates provides a full range of probabilities against which worst-case scenarios can be identified and levels of security defined. Originally, architectural models started to be introduced inside wind-tunnels to test preventive designs against structural collapses due to overload generated by wind forces. Similar experiments are also used to optimize the design of industrial facilities such as nuclear power plants and chemical factories against potential leakages. More recently, they became operative in mitigation planning against atmospheric violence in urban environments. The techno-scientific procedure employed is based on the formal elaboration of an “accident/attack” in an atmospheric-urban model, allowing scientists and architects to forecast impacts and estimate risk. Digitally measured and calculated, the data generated through the model allows to infer on what would have happened, for example, if a dangerous gas was released at the corner of Merylebone Road with Gloucester Place in central London, on a sunny warm day, with north-winds coming 51 degrees to the right from the north-south axes of the street at 2 meters per second.

A model of London central area being tested in the wind-tunnel of The National Centre for Atmospheric Science (NCAS), UK.