Many major cities across the globe are introducing ultra-low emission zones or ULEZ. There are different types of ULEZ zones, the most common is a charging zone. In a charging zone there is cost for using your car in the zone if you are in a car that meets specific standards. These standards are extremely strict on diesel cars and not very strict on petrol cars. The idea is a development of a previous scheme known as smokeless zones. Many of these zones are already in cities such as London and Birmingham.
Other zones target specific types of vehicles like trucks to try and minimize certain parts of the road vehicles that are the most damaging to the environment. So rather than charging the type of vehicle simply cannot enter.
The objective of the zones is to try and lower the amount of pollution on the street, and more specifically lower the amount of the most damaging pollution on the street. This will make it more pleasant and have long term health benefits of minimal pollution exposure. The specific pollutant it is fighting is nitrogen dioxide which is mainly emitted from cars. This will not affect things like particle pollution as even electric cars degrade the road and through up particles.
To asses the impact of these zones people will have to look over a large period of time as levels of pollution naturally vary due to temperature, weather and other factors. The hope would be that this would help to encourage electric cars so you would have to pay to get into these zones and the overall air quality would be much cleaner.
These are good ideas to solve an ever more pressing issue but there are other simpler ways in which individual people can help simply by taking the bus instead of the car. Think of the local busy street in the morning you could replace around 65 cars with 1 bus, think how much better that would be.