A ir quality implications of coal-ammonia co-firing

H owever, if t he ammonia is p roduced via t he grey/brown m ethod, t otal emissions of carbon dioxide will not change, as the reduced carbon dioxide emissions a t power plants in J apan will be entirely o ffset by increased carbon dioxide emissions o utside of Japan w here the a mmonia i s produced (Stocks e t al., 2022). [...] The p roduction, transport, and combustion of both coal and ammonia have the potential t o affect PM 2 .5 t hrough t he emissions of v arious s pecies. [...] C oal c ontributes to t he formation of P M 2.5 t hrough e missions of P M 2.5 during t he mining of coal, a nd through e missions of P M 2.5 , n itrogen dioxide and sulphur dioxide during t he burning of coal. [...] The increased emissions at Unit 4 of H ekinan Thermal Power S tation w ill likely increase a tmospheric concentrations o f PM 2.5 a s the m agnitude of emission i ncreases are substantial (30-75 %), and as it i ncludes i ncreases in e missions of ammonia, w hich is an e specially s trong precursor o f PM 2.5 ( Gu et a l, 2021). [...] Indeed, the authors of the research p erformed by t he p ower companies conclude that “…evaluation of c ombustion c haracteristics o n an actual scale and e valuation of various coal t ypes and c ombustion conditions assumed for operation a re i nsufficient, and further technical studies are desired in the future prior t o commercialization.