As a hiker in Hong Kong, I am very passionate about the environment and the air that we have no choice but to breathe when exploring Hong Kong's wild side.

Air pollution in Hong Kong, to be honest, is pretty bad. Sure, it's not as bad a Beijing or other areas in China, however, when compared to other countries/places in the World, Hong Kong is pretty darn filthy.

General air pollution used to be of the most concern in Hong Kong, however recently the focus has been made on roadside air pollution, with general air pollution coming in at a close 2nd.

Of course roadside air pollution is the major concern, as unfortunately when compared to the greater population of Hong Kong, most people are working during the day in congested areas of the city.

Now, the Government are using pollution monitoring stations which measure something called PM10. PM is one of the major types of air pollution that is harmful to our health. PM stands for Particulate Matter.

The "10" stands for the size of the particulate matter that is being measured. So, PM10 is Particulate Matter up to the size of 10 microns. To most people this means nothing, but for me, having worked closely with Clear The Air (CTA), a local anti air pollution group, PM10 is outdated and an inaccurate measure of how pollution affects our health.

PM10, being of a greater size, tends to settle to the ground after a few hours, and we don't breathe in an awful lot of it due to it's larger size. It is also less harmful to our health.

PM10 is a largely outdated way to measure air pollution. Hong Kong's air pollution monitoring systems are based on a 20+ year old standard. This means that the figures that the Environmental Protection Department (EPD) are giving us are largely inaccurate.

For example today, the Central roadside air pollution reading is 135. This doesn't mean a whole lot to the general population due to the fact that they are quite used to Hong Kong's poor air, and have generally accepted it as the norm.

So what does 135 mean? Well, for starters, based on Hong Kong's outdated system, the air is hazardous and it is recommended that people avoid roadside situations and in general refrain from vigorous outdoor exercise. If this were a Typhoon, it would be a T8; offices would be closed, transport would be shut down, and Hong Kong would be a ghost town. A very polluted one.

In all honesty, I believe that there should be a warning system similar to that of our Typhoon warning system. After all, just as a Typhoon is hazardous to our health and well being, so too is air pollution. If Hong Kong was placed on a T8 right now, don't you think that the Government would be doing more to clear out skies of air pollution? Especially considering that yesterday roadside air pollution was even higher at 145. How many days would be working days at the present time if we had an air pollution warning system that prevented workers from going to work and shut down transportation throughout the city?

However, having said that, the EPD are using measurments that are outdated by over 20 years, introduced in 1987. That is a long time ago. Let me ask you what has changed in the past 23 years? For a start, your baby is now 23 years old, working in the polluted city, and breathing in air that is as old as him/her so to speak.

So if we shouldn't be measuring PM10, then what should we be measuring and reporting on? 

Considered as a standard throughout the World in most developed countries is PM2.5, with some countries going beyond that and measuring PM0.1.

PM2.5 is the most hazardous to our health. Particulate matter up to the size of 2.5 microns is absorbed easiest by our lungs, causing the most damage. Although PM0.1 is absorbed even more than PM2.5, PM2.5 is a more realistic figure to aim for, and certainly a lot more accurate than PM10.

Similarly, in Beijing, PM10 is the standard. Going by that standard, the pollution was so horrific in Beijing last week that almost 700 flights were cancelled.

However, the US embassy in Beijing are monitoring PM2.5 on their rooftop. During this same period, the US embassy recorded a level that was beyond their index. They measured PM2.5 at 522. Needless to say, 522 is beyond bad. Going by the World Health Organization (WHO) standard for PM2.5, this reading is 52.2 times more. OK then...

So what would it be like in Hong Kong? Well, surprisingly enough, the EPD already know what it is like as they have been measuring PM2.5 for some time now. So why is it not a figure that is divulged to the public? We can only guess that the readings are so high, that to divulge that information would cause an outrage among the citizens of Hong Kong. And rightly so. Therefore it is kept hush hush. As are most things that don't meet regulations, such as the environmental impact report that was recently bypassed when approving the Hong Kong Macau bridge, but that is another story.

Now in Beijing there is a green group called Green Beagle, who have their own PM2.5 monitoring device, and who release their information to the public, much to the dislike of Beijing's Government. This has recently put much pressure on Beijing to change it's ways to adopt a stricter standard.

Unfortunately I was not able to find the Green Beagle website, and hence the PM2.5 readings in Beijing, most likely due to the fact that it is probably being blocked by the Great Firewall of China.

In Hong Kong however, we do not have a great firewall, therefore any statistics that would be released, would indeed be public for the World to see. One thing that Clear The Air have found is that embarrassing the Hong Kong Government is the one, most relevant way, to make them act on something of high importance.

The exposure of PM2.5 readings would do just that, and that is why Clear The Air have taken it upon themselves to source out a PM2.5 monitor to publicize Hong Kong's frightening results.