A team of researchers has found a way to detect trace gases down to concentrations at the parts-per-quadrillion level using a new variation on the photoacoustic effect, a technique that measures the sound generated when light interacts with molecules. “In many ways, the photoacoustic effect is already the most practical method available for detecting pollutants Read more about New photoacoustic technique detects gases at parts-per-quadrillion level[…]