Vacuum ultra-violet emission by the a′1Σ–u state of N2 and by N((3P)3s(2P)) have been detected in active nitrogen together with the previously reported Lyman-Birge-Hopfield bands. The a′ state is populated and removed by atomic nitrogen in the reaction N(4S°u)+ N2(B3Πg)⇌ N2(a′1Σ–u)+ N(4S°u) and quenching by N2 but not radiation is also significant in removing the a′ state.