Ted Cushman

In the 17th century a fellow named John Mayow put small animals in jars with candles and studied how long it took them to die of asphyxiation. By doing so, he proved the existence of a special component of air that keeps us alive. What he termed “nitro-aerial spirit” we know now as oxygen. Combustion and breathing both use it up in an enclosed container, so we need some way of replenishing this “spirit.” Knowing what’s necessary to keep us alive is a start, but there’s far more to ventilation and indoor air quality than that.

In the 20th century, ventilation research had advanced to studying humans in confined boxes. Rather than asphyxiating the subjects, however, this time the researchers ran controlled amounts of ventilation air through the boxes. The objective was to find the minimum ventilation rate at which trained smelling judges would deem the odor of the...

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