Fig. 4: ULEZ1 implementation and spillover effects on NO2 and NOx in London.
From: Further improvement in London’s air quality demands more than the Ultra Low Emission Zone policy
Estimated effects are shown for (A) three months and (B) eleven months after ULEZ1 implementation at urban traffic sites, in central, inner and outer London areas for NO2 and NOX indicating the "positive" ULEZ1 effect across central to outer London.
