happens here closely. many other cities in the uk are planning similar emissions zones. birmingham has already introduced one — stephen arnold is head of the city's clean air zone and hejoins me now. i think ithinki i think i am right that you enter your clean air zone i think i am right that you enter your clean airzone in i think i am right that you enter your clean air zone injune. what difference has it made? your clean air zone in june. what difference has it made?- your clean air zone in june. what difference has it made? thank you for invitin: difference has it made? thank you for inviting us _ difference has it made? thank you for inviting us one. _ difference has it made? thank you for inviting us one. it _ difference has it made? thank you for inviting us one. it is _ difference has it made? thank you for inviting us one. it is very - for inviting us one. it is very early days. we are cautiously optimistic so far. we have seen an improvement in the volume of compliant people entering the zone so that means the most polluting vehicles are not coming into the clean air zone, fewer of them, and we get about 100,000 vehicles every single day. there are many more journeys on top of that. we are cautiously optimistic. we think it