Low-cost light scattering monitors (LCMs) are promising tools as alternatives to research grade, higher-cost instruments to provide real-time, high resolution monitoring of fine airborne particulate matter (PM) thereby supplementing traditional filter-based gravimetric methods. The LCMs must however be calibrated to get correction factors (k_cf) to be comparable to research grade instruments that serve as benchmark instrument for reporting PM mass concentrations. This study aims at evaluating k_cf of five commercially available LCMs, namely YesAir operated in diffusion mode (YAd), YesAir operated by internal pump (YAp), Aeroqual S500 (Aq), NuoFang SDL607 (NF) and Dylos DC1700 (Dy), against a TSI DustTrak Environmental Aerosol Monitor 8540 (DT) benchmark instrument. The evaluation is based on three individual particle sources: burning of candle, cigarette and incense. The obtained k_cf was found to be dependant on both source and the mass concentration of PM_2.5. Depending on the LCM and source, concentration dependency of k_cf values at five concentration ranges (0-5 µg/m³, 5-20 µg/m³, 20-50 µg/m³, 50-100 µg/m³ and 100-1000 µg/m³) shows that k_cf follows one of the five patterns over the concentration range: (1) decrease, (2) constant, (3) constant then decrease, (4) decrease then constant and (5) decrease then increase. On the other hand, correlation expressed as coefficient of correlation (R²) increases when PM concentration increases. The results demonstrated the challenges in calibrating LCMs for their application in real-world PM monitoring campaigns.