Two winners have been chosen in this year's City of Dreams Pavilion Competition, with one constructed from air-filled materials and the other with an inverted pyramid that is a comment on environmental instability.

The City of Dreams Pavilion Competition is run by FIGMENT, the Emerging New York Architects Committee of the American Institute of Architects New York Chapter and the Structural Engineers Association of New York.

It is based on the concept of a future in which there are strains on our economic and natural resources and aims to promote sustainable architecture and design.

This year's winners – The Pneuma by Ying Qi Chen and Ryan Somerville and Repose Pavilion by Parsa Khalili – were chosen by the jury "for creatively engaging with the competition’s prompt to reconsider the architectural profession’s relationship to material waste and sustainability."

The Pneuma is based on the principle that construction hinges on two factors: weight-to-volume ratio and scalability. Instead of traditional rigid materials, it uses components like recycled exercise balls, cradle-to-cradle fabric and rented scaffolding to create elements including canopies and seats.

Repose Pavilion employs "an architecture of perceived instability" to challenge viewers to consider where architecture and society will go next in a world that is increasingly environmentally unstable.

An inverted pyramid balancing on top of another pyramid gives a sense of imbalance, commenting on "society’s shift from a stable ecology to an unstable one, from solidity to fragmentation, from stasis to imbalance, from the natural to the manmade."

The Pneuma will be assembled on Roosevelt Island in New York City's East River and will be open to the public for a month from 6 June.