Vehicle emissions are a significant source of air pollution in the urban environment worldwide. Vehicles that run on petrol and diesel emit harmful chemicals (carbon monoxide, nitrogen oxides and hydrocarbons). In particular, many older cars that are still on the roads are heavy emitters.
But in Hong Kong a sensor-based project is ready to change urban air quality.
A generalized control
Cars exhaust fumes contain poisonous gasses that cause lung cancer, heart failure, asthma and other diseases.
To identify the worst-offending vehicles, Hong Kong installed sensors on highway ramps. These sensors use infrared and ultraviolet beams to detect roadside emissions in tailpipe exhausts of passing vehicles.
An effective intervention
The combination with cameras allows them to capture the license plates of the most polluting means of transportation, so their owners can be notified.
Lastly, the owners are required to repair their vehicle and pass an emission test, before their vehicles are allowed back on the road.
A real implementing enforcement programme
This operation is therefore not aimed at monitoring, but it is a real implementing enforcement programme.
Since the research began in September 2014, more than 16.000 high emitting vehicles were identified by remote sensing. Among them, 96% have been fixed and passed the compulsory emissions test.
An immediate change
The program led to a significant and continuing reduction in the level of harmful chemicals and to a rapid improvement of air quality in Hong Kong.
The key is targeting the small portion of high emitters for vehicle emission control. This operation reduces the repair cost and time, compared to passive sampling or periodic inspection.
Given the results, we do not understand why this low-cost technology is not adopted by a growing number of nations to offer their citizens a quick and far-sighted solution to clean the air.
Sources: newscientist.com, eandt.theiet.org
