In comparison, Ch almost presented a unimodal distribution. NOx also increased the first peak concentration rapidly, similarly to SO2. At a given combustion temperature, Ch had the highest NOx emission peak concentration followed by En, and Sa had the lowest value. NOx emissions increased with increasing combustion temperature. Moreover, increasing temperature accelerated the formation of the second peak for Sa. In the range of 700e900 C, the conversion ratio of nitrogen fluctuated but stabilized on the whole for each algae biomass species, with 9.30e9.10% for En, 34.03e34.98% for Sa and 6.73e5.90% for Ch.