<p>A novel method for atmospheric network design is presented, which is based on Information Theory. The method does not require calculation of the posterior uncertainty (or uncertainty reduction) and, therefore, is computationally more efficient than methods that require this. The algorithm is demonstrated in two examples, the first looks at designing a network for monitoring CH<sub>4</sub> sources using observations of the stable carbon isotope ratio in CH<sub>4</sub> (δ<sup>13</sup>C), and the second looks at designing a network for monitoring fossil fuel emissions of CO<sub>2</sub> using observations of the radiocarbon isotope ratio in CO<sub>2</sub> (∆<sup>14</sup>CO<sub>2</sub>).</p>