Two things stand out in WWF Hong Kong chief Eric Bohm's decision to quit the city 31 years after arriving from Canada and settling here. His public campaign against air pollution had become very personal and he blames flaws in our political system for lack of progress.
The 68-year-old former businessman's decision to move to Britain reflects the disappointments over eight years of fighting to improve the quality of our air. But it was prompted by the desire to spare his asthmatic wife from having to breathe it any longer after two bouts of pneumonia within a year, which he says were triggered by bad air and irritation.
The recently introduced ban on engine idling illustrates his frustration with the political system. It should have been one of the unqualified legacies of his eight years with WWF, the city's biggest green group. Instead, under pressure from the transport lobby, the government watered it down with exemptions and concessions to the point where it has become the idling ban you have when you don't have one. Bohm cites this as evidence of the stumbling block to environmental progress posed by a political system that responds to vested interests rather than public opinion, and a civil service that is reluctant to rock the boat.
But he has not lost hope. He says, rightly, that Hong Kong people do care about the environment and trusts that chief executive-elect Leung Chun-ying, neither a tycoon nor a former civil servant, will reflect this by revealing a vision of what the city should be like to look at and live in.
Failing that, there is the prospect that, from 2017, Hong Kong will have a chief executive elected by universal suffrage who will have more reason to take public opinion into account.
If Leung wants the honour of being the city's first elected leader, he should use his first term to show that he takes air quality seriously. In that respect, his environmental advisers are right to acknowledge the need for a show of strong political will - conspicuously absent up to now - and better policy integration between different departments.
If Bohm did not already have a good reason for leaving, the government has just provided him with one - the decision to extend the franchises of three bus companies by 10 years with no more than cosmetic provision for fast-tracking the retirement of old, polluting vehicles. Harmful levels of roadside pollution in built-up areas are mostly attributable to buses and trucks using 'dirty' engines, whether old or merely poorly maintained.
If Leung is to have any credibility on the environment, he needs to revisit issues like idling engines and polluting buses. He could start by making an exception of these buses and subsidising their private owners to fast-track their retirement.