Roadside checks will stop lorries, buses, taxis or cars suspected of breaking the law. Examiners from the Vehicle Inspectorate will work with police in the checks.
If a vehicle's exhaust emissions are unlawful, the owner will have to take the vehicle off the road straight away - after being allowed to take it home or to a garage; in other cases, the owner will have 10 days to have the fault put right.
Launching the crackdown, near the Rotunda in Birmingham city centre, Mr Watts said: 'We are absolutely determined to make sure we are doing everything possible to force polluting vehicles off the road. That's why we have given the go-ahead for these roadside checks.