This work assessed the ambient air particulate matter (PM) concentrations in three sites in Orlu urban in the dry and wet seasons using Aerocet-531 particulate monitor. The particulate matter size monitored were Total Suspended particulate(TSP),Particulate matter less than ten micro meter(PM10) in diameter and particulate matter less than two and half micrometer( PM2,5).The result showed dry season mean concentrations of 105.94±23.96, 68.31±9.72, 29.06±10.57μgm-3 for TSP PM10 and PM2.5 respectively in site 1; 122.00±22.09, 83.31±17.29, 30.25±18.87μgm-3 for site 2 and 92.13±18.16, 59.44±15.74, 22.19±3.63 μg.m-3 for site 3. Results generally show that site 2 PM concentration > site 1 > site 3. The highest PM concentration was recorded in January while the least was in the month of September. Student t-test statistics showed that in the dry season only PM2.5 in sites 1 and 2 were significant p<0.5 while PM10 in sites 2 and 3 were significant in the wet season. The coarse particulate pollutants levels in the three sites were within the WHO guideline limit for ambient air whereas the fine particulates (PM10, PM2.5) in the dry season exceeded the WHO guideline limit for 8 hours averaging period.