A method and device for manufacturing extremely fine particles and porous materials by controlled low temperature drying. An ambient-pressure and ambient-temperature atomizer atomizes a particle precursor solution to create a precursor mist. The precursor mist and dryer gas are fed into a dryer tube through a tangential inlet (swirl generating inlet). The mixed stream forms a helical flow structure within the dryer tube. The swirling mist undergoes drying and particle formation at a relatively low temperature. The flow continues to swirl and drying process continues with repeated passes until the required drying duration is reached. This dryer structure allows for a compact dryer with full control of residence time.