Fig. 2: Concentration characteristics of VOCs in the PRD urban agglomeration.

a–e Concentration profiles of the main compounds of different types of VOCs in GZ, DG, SZ, and HZ. f Regional concentrations of VOCs across the PRD urban agglomeration.

a–e Concentration profiles of the main compounds of different types of VOCs in GZ, DG, SZ, and HZ. f Regional concentrations of VOCs across the PRD urban agglomeration.