The present work determines the temporal and size distribution of polycyclic aromatic hydrocarbons (PAHs) concentrations in tropical urban air in Kuala Lumpur, Malaysia. Particulate matter (PM) fractions were assessed using a nanosampler in accordance with the seasonal cycle in Malaysia. The 16 USEPA priority PAHs were analyzed by gas chromatography mass spectrometry (GC–MS). The health risks were quantitatively determined the exposure risk of two selected population groups based on incremental lifetime cancer risks (ILCRs). Results indicate that ∑16PAH concentration was highest during the southwest (SW) monsoon (15.8 ng m−3). The high molecular weights of PAHs dominated 65% to 85% of the total PAH. Approximately 71.7% to 80.7% of indeno(1,2,3-cd)pyrene, dibenzo(a,h)anthracene, and benzo(g,h,i)perylene were concentrated as fine particles (PM0.1–0.5, PM0.5–1.0, and PM1.0–2.5), and unimodally during the SW monsoon. Principal component analysis (PCA) and positive matrix factorization (PMF) determined that the PAH have originated mainly from vehicles and engines emission with 24.7% and 23.7%, respectively. The total percentage of benzo(a)pyrene equivalent (BaPeq) concentration in the PM<0.1 was found to contribute to more than 50% of the potential health risk. The health risk assessment further showed that the estimated ILCRs due to PM BaPeq exposure is negligible.