Assessing the Applicability of Photocatalytic-Concrete Blocks in Reducing the Concentration of Ambient NO₂ of Chandigarh, India, Using Box–Behnken Response Surface Design Technique: A Holistic Sustainable Development Approach

Table 1

Three levels of the process parameters used during the optimization process.

S. no.	Process parameters	Symbolic representation	Units	Coded values
				−1 (low)	0 (medium)	+1 (high)
1	Concentration of TiO2	X1	g	1	3	5
2	UV-A irradiance	X2	mW/cm^2	1	3	5
3	Relative humidity	X3	%	10	40	70