Aims: This study explores the influence of meteorological parameters such as wind direction, wind speed, rainfall, air temperature and relative humidity on PM2.5 and PM10 concentration. Place and Duration of Study: The study was conducted in Woji, an urban area of Port Harcourt city in Nigeria, between May and December 2019 covering wet and dry season. Methodology: The PM10 and PM2.5 concentrations were monitored for 236 days using photometric laser based particulate monitor while meteorological parameters were collected using Misol weather station mounted 10m above ground at Woji monitoring location. Results: PM concentration for all the months under study were below USEPA 24-hr standard except the month of December with PM2.5 = 58.8 μg/m³ and PM10 = 164.5 μg/m³. The result showed a significant but positively strong correlation between PM2.5 and PM10 (r = 0.97, P < .001). The wind speed significantly influenced PM2.5 and PM10 concentration with a weak negative correlation (r = - 0.22 and -0.23) respectively at P < .001. Also, PM2.5 and PM10 concentration exhibited a weak negative but significant correlation with rainfall (r = - 0.05 and -0.05) and air temperature (r = - 0.12 and -0.14) respectively at P< .001. Relative humidity showed a weak negative but not significant correlation with PM2.5 concentration (r = - 0.01) while PM10 exhibited weak but significant correlation with relative humidity (r = 0.04). Conclusion: The PM concentration exceedances recorded in month of December could be attributed to dry dusty north east trade wind that comes with harmattan as well as high atmospheric stability which is associated with low wind speed. The study revealed that meteorological parameters such as temperature, wind speed and rainfall plays significant role in the reduction of particulate matter loading through air dispersion, atmospheric instability and washout process  while relative humidity increases PM10 concentration.

Particle pollution poses serious public health concern because of its potential to find its route into human lungs thereby causing respiratory diseases and cancer. This paper analyses various aspect of particulate matter including seasonal variation, Particulate matter based AQI, particulate matter exceedances and empirical modelling for seasonal prediction of PM2.5 and PM10 concentration. The study was carried out in Woji, a residential urban area of Port Harcourt, Nigeria, between May and December 2018. The Particulate matter concentrations were monitored with particulate monitor while meteorological variables were also monitored with Misol weather station. The 24-hour average PM10 concentration for dry and wet seasons were 139.6 μg/m³ and 97 μg/m³ respectively. These concentrations are below USEPA 24-hr standard (PM10 = 150 μg/m³) while the 24-hour average PM2.5 concentrations of 46.1μg/m³ for dry season exceeded daily limit (PM2.5 = 35 μg/m³) but was below the limit in wet season with concentration of 29.1 μg/m³. The study area experienced daily PM2.5 and PM10 exceedances of 33.3% and 19.7% respectively for the study period. Also, the PM based AQI were unhealthy to all residents for 13%, unhealthy to the sensitive group for 20%, moderate for 62% and good for 5% of the monitoring period. PM2.5 and PM10 pollution prediction model were developed for dry and wet season with a high correlation coefficient of 0.98 and 0.97 respectively at (P < 0.001).The seasonal variation of PM concentration revealed that PM10 and PM2.5 concentration varied from season to season, with significantly higher concentration in dry season than in wet season. The air quality of Woji Port Harcourt was better in wet season than in dry season due to the scavenging mechanism of rainfall. Also, PM exceedances were higher in dry season than wet season due to high atmospheric stability associated with low wind speed in dry season.

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.