On june16th, the Environmental Protection Department (EPD) of Hong Kong published the 2013 Emission Inventory for Hong Kong (one would have expected the 2014 one…). According to this report, Hong Kong's total emissions in 2013 were 31 280 tonnes of SO2, 113 220 tonnes of NOx, 29 420 tonnes of VOC and some tonnes of other dirty gazes (details can be found there). It is advocated that compared to 2012, the levels of the six major pollutants in 2013 were between 1 and 11 per cent lower, mainly due to a reduction in emissions from vessels and motor vehicles.But are HK emissions important for HK air pollution? Depending on who you speak with (people who own a car, people from the government, MTR users etc…) the answer does vary. In fact the usual suspect for HK air pollution is mainland China. And the usual answer when you do not have conflict of interest nor any particular information is 50% is coming from HK emissions and 50% is coming from mainland China.
At the School of Energy and Environment, Dr. Nicky Lam and Glory Kwok Lee Kan who is a PhD student have carefully addressed the subject, and are developing a new statistical model to predict the air quality in Hong Kong as well as the source of this pollution. Interestingly, the PM10 mainly come from mainland China (80% in January!). But it is not always true: from May to September included, more than 50% of PM10 are generated by Hong Kong. These are not the most heavily polluted months but it is also true for February and March. Last but not least, HK has to be taken responsible for most NO2 and SO2 generation.And now guess what Hong Kong is doing? Quietly waiting for mainland China to do the job in emission reduction. But with this information about air pollution sources, HK SAR authorities have now to seriously consider doing something too. Which means ultimately understand that pollution is an externality generated by economic activity and is an issue that, by definition, cannot be spontaneously addressed by the market.