Abstract: The study investigated seasonal variation of particulate pollutant concentrations in parts of Port Harcourt Metropolis, Rivers State, Nigeria. The study adopted descriptive research design which involved the description of particulate pollutant concentrations in the study area. The study assessed PM2.5, PM10 and PM1.0 as well as meteorological parameters in eight (8) locations (Rumuola, Rukpokwu, Elioparanwo, Mgbuoshimini, Rumuokurushi, Oroworukwo, Trans-Amadi and Port Harcourt Township) for both the wet and dry seasons. It was reported that, PM2.5 during the wet season in all location was above WHO permissible limit. Also, the concentrations of PM2.5 and PM10 in the dry season for all the locations were above WHO permissible limit of air quality guidelines. It was recommended that, legislation measure should be put in place to curb this menace, alternative sources of fuel should also be adopted.

Keywords: Atmosphere, Environment, Particulate Matter, Pollutant Concentrations, Port Harcourt, Rivers State.

| DOI: 10.17148/IARJSET.2025.12203