Temporal Variability of Particulate Matter in Urban Area of Port Harcourt, Nigeria

Particulate matter pollution poses serious health concern to public health in Nigeria especially at elevated concentration. Its size is very vital in determination of its long stay in the atmosphere as well as its deposition in human respiratory system. This study analyzes the temporal variation of particulate matter (PM10 and PM2.5) concentrations and its ratio in urban area of Port Harcourt. The study was carried out in Woji, area of Port Harcourt, Nigeria, from May to December 2018 using Aerocet 531 particulate monitor while meteorological variables were monitored via Misol wireless weather station mounted 10 m above the ground level. The highest particle pollution occurred in the month of December with an average daily PM2.5 concentration of 58.8 μgm-3 and PM10 concentration of 164.5 μgm-3, which exceeds WHO and USEPA daily threshold. These particle pollution exceedances recorded the dry season month of December was due to high atmospheric stability with dry dusty north east trade wind associated with harmattan. Also, Particulate matter concentration are usually lower during the weekends than weekdays with high PM level occurring at night from 8:00 PM to 9:00 AM in the morning with the peak at 8.00 AM. This shows that the weekdays experienced elevated PM level than weekend as a result of high industrial, commercial and traffic activities emitting particles within the weekdays. Also the average PM2.5/PM10 ratio for wet and dry season was 0.3 respectively. This shows that the town is town is predominated by coarse particle.