The day-to-day negative effect of contaminating substances on the NOx removal effectiveness of photocatalytic surfaces and their recovery capacity after undergoing cleansing is of real academic and practical interest. This paper analyzes the NOx removal effectiveness of two different types of photocatalytic concrete surface layers incorporating nano-TiO2 particles. Both types of surfaces are examined before and after being subjected to dust accumulation and oil impregnation. The recovery of their NOx removal capacity after undergoing various cleansing processes is also evaluated. The results are compared to those of their respective reference samples. The results show that the high NOx removal capacity of the spray-coated samples is partially maintained even after a high concentration of dust accumulation. However, the water-cleansing process employed is sufficient to recover the lost NOx removal capacity. It is also discovered that the nano-TiO2 particles lose nearly all their photocatalytic capacity after being subjected to oil impregnation, and that the cleansing processes, either by an alkaline detergent or using an n-hexane solvent, fails to recover the initial NOx removal capacity.