Hong Kong has recently demonstrated its ability to use smart city sensors to monitor air quality and identify vehicles that are particularly troublesome for pollution. What challenges does air quality control present, how did Hong Kong achieve its ability to reduce emissions, and what does this mean for the future of monitoring technologies?

What challenges does air quality control present?

As the world population continues to grow and the dependency on automotive increases, cities are under increasing pressure to improve their air quality. Polluted air is well known to be a major contributor to early deaths and many respiratory diseases, and the high density of people living in cities magnifies this effect.

In the past (pre-1900’s), most air pollution in cities came from industrial sites that were commonly placed next to or inside the city itself. However, the invention of the automobile, along with better public transport, allowed these industrial sites to be located much further away from the city, which helped eliminate industrial pollution from cities. But the introduction of automobiles just replaced one kind of air pollution with another, and the 1900s saw cities worldwide struggle with air quality.

Fast forward to modern times, and many technological developments and regulations have helped reduce the impact of air pollution. For example, modern cars use catalytic converters, which help to reduce levels of carbon monoxide and nitrous compounds from car exhaust, while the banning of coal and wood chimneys has reduced the amount of soot being formed from fireplaces.

But there are still challenges faced with controlling air quality, and one of these is identifying vehicles that produce above normal levels of pollution. While vehicles can be emissions tested during service, this requires a vehicle to be serviced, and the emission readings may not even be accurate (such as the VW scandal). Thus, a vehicle that produces large amounts of pollutants can drive through a city, but how can the vehicle be identified even if environmental sensors detect this?

Hong Kong demonstrates the first smart city air quality control solution that works

Smart city technologies have started to grow in popularity, but those that monitor air pollution can generally do very little except for informing city planners where traffic is a problem. However, Hong Kong recently demonstrated a new system that monitors air quality and can even identify vehicles that are causing trouble.

The system utilises infrared and ultraviolet beams installed on highway ramps, and these beams are then detected by spectrometer sensors. This allows for gases such as nitrogen oxides and carbon monoxide to be measured in real-time. A combined camera system can then image the vehicle that was found to be producing too much pollution. A message is then sent to the vehicle owner informing them to get

their vehicle checked. Furthermore, the vehicle is banned from driving on roads until this check is done.

The program (which has been running since 2014) has managed to remove over 16,000 high emission vehicles, with 96% of these vehicles being repaired and put back to use, proving that emission reduction does not need to be expensive. It was also determined that the decrease in emissions due to the new technology has been between 25% to 28%.

What does this mean for future monitoring systems?

While smart city sensors have been deployed before, this is the first time such sensors are being used to enforce rules and policies. Thus, the data gathered by the sensors has an immediate effect on the environment instead of a gradual effect that takes decades to implement.

However, it is concerning that smart city technologies can identify and track individuals while recording data regarding them. In the case of the Hong Kong system, only vehicles are being tracked, and only to monitor their emissions levels. But a more sophisticated system may be able to detect socially bad habits of individuals in crowds and then use facial recognition to identify the individual and keep a record of what they are doing. This is something that China already does, and such bad habits contribute to a poor social credit score which, if too low, prevents the use of transport services and access to facilities.