The randomness of firecracker-burning site and the overlapping impact of multi-sources makes the source apportionment of PM2.5 during the firecracker burning events more difficult. To investigate the influences of the downwind distance to the firecracker-burning site on the temporospatial distribution of PM2.5 and public health risk, PM2.5 were sampled at three sites adjacent to a fixed firecracker-burning route accompanied with annual pilgrimage activity during the Lantern Festival in Taitung, Taiwan, which had a low background PM2.5 concentration. The metallic elements, water-soluble ions, carbonaceous contents were analyzed. The potential sources were identified using positive matrix factorization. Finally, the health risks were assessed by calculating the hazard quotient and incremental lifetime carcinogenic risk, respectively. The results showed that the average concentration of PM2.5 on the event days increased by approximately five-fold compared to the non-event days. The increase of chemical components varied significantly from the distance to the burning site. The concentrations of K, Fe, Al, Mg, K+, Cl– and OC rose by 6–14 times at one site close to a site with intensive firecracker burning, while increased by 2–6 times at one site far away from the firecracker burning sites. The PM2.5 increment on the event days was mostly attributed to firecracker burning, kitchen fumes, and mobile sources. The health risk assessment results showed that the hazard index differed between the sampling sites. Furthermore, the cancer risk of one site close to the firecracker burning site was over the threshold, while that far away from the site was below the threshold.