Emissions wise no - unless they have multiple reports of the same thing they probably won't do much unless it is very obvious that something inappropriate is going on with the vehicle with regard to emissions - chances are it was a one off due to the engine being cold, etc. etc.
At least around here though the police are very hot on dangerous driving if submitted through the appropriate web-site (Operation Snap) and they've taken action against loads of drivers due to it - they also don't like busy bodies though either and have taken action against some of the uploaders as well in some cases (
https://www.youtube.com/watch?v=msm4CFNqWBU )
I've only ever bothered contacting the police twice and I've seen many cases of bad driving but these 2 were extremely dangerous.
The other incident was extremely late at night on a country road very twisty and some moron blazed past me on a blind corner and I don't drive slow. They then immediately as soon as they were in front of me slammed the brakes so I had to as well even though nothing was in front of them. They then proceeded to swerve all over the place. I basically put the car to a crawl to let them make some space as they were now after overtaking like Schumacher driving like they were asleep at the wheel.
They hit the kerb a few times and I'm thinking either drunk or having a stroke or on drugs so called the police. They mounted the pavement and luckily it was late with no dog walkers or walkers in general about. They could have killed someone.
Again police took reg and never heard anything. They didn't want dashcam footage or a witness statement.
I don't go to the police unless I think they genuinely should be doing something.
Imagine if that person hit a child or crashed into someone else and killed them? Both could have caused serious damage and likley will do one day.