Table 6.

R² of different distribution using different optimized algorithm. The data in bold denotes that it is largest in each line of Table 6, which represents the optimal R² of distribution fitting.

Indexes	Optimized Algorithm	Evaluation Criteria (R2)
		Weibull	Gamma	Lognormal	Log-Logistic	Inverse Gaussian
PM2.5	BBO	0.9918	0.9904	0.9919	0.9980	0.9998
	BBODE	0.9919	0.9937	0.9994	0.9980	0.9998
PM10	BBO	0.9879	0.9634	0.9760	0.9970	0.9991
	BBODE	0.9898	0.9937	0.9989	0.9982	0.9993
O3	BBO	0.9984	0.9979	0.9870	0.9950	0.9963
	BBODE	0.9994	0.9997	0.9968	0.9952	0.9966
SO2	BBO	0.9747	0.9820	0.9944	0.9916	0.9942
	BBODE	0.9838	0.9827	0.9947	0.9918	0.9970
NO2	BBO	0.9971	0.9990	0.9901	0.9970	0.9991
	BBODE	0.9971	0.9993	0.9990	0.9974	0.9991
CO	BBO	0.9774	0.8257	0.9962	0.9894	0.8309
	BBODE	0.9811	0.9899	0.9962	0.9968	0.9963