This thesis first reports a new method for quantifying phosphorus (P) with various forms in solid fuels. Based on this method, P transformation during pyrolysis was then investigated. In situ volatiles with distinctly-different chemistry during volatile−char interactions could significantly affect char structure, reactivity and particulate matter (PM) emission during combustion of P-containing solid fuels. Water vapors are also found to substantially influence PM emission during combustion of volatiles and char from P-containing solid fuels
