Financial Times, 15 Dec 15:
Calvin Quek claims that levels of PM 2.5 in China are 15% lower this November than last year and that this can be attributed to government action on air pollution (Chinese authorities are responding to air pollution problem Letters Dec 11). Clearly levels of small particulates are subject to weather conditions which I suspect is a more likely explanation for the short-term fluctuation that he has documented. In any event 17% of deaths in China are now attributable to air pollution, which makes it the biggest cause of mortality apart from smoking.
If one considers Bejing, levels of PM 2.5 peak in the early morning, an anomalous observation explained by the fact that this is when diesel-powered lorries make deliveries to the city centre. Although these lorries carry certificates that they are compliant with government regulations, most of them carry no pollution control devices of any sort, so NOx and particulates are vented straight into the night sky. Traffic police are not allowed to ban such vehicles if they are making “essential deliveries” which all claim to do.
The factories that supply these untrapped vehicles claim that they are only for export to Africa. Government legislation that allows both drivers and manufacturers to be prosecuted have been on the statute books for more than a decade, but so far there has not been a single prosecution.
So I am perplexed how Mr Quek concludes that air quality in China is improving as a result of government action. My concern is that China’s decision to close factories during a recent smog alert was a cosmetic exercise cynically timed to coincide with the Paris summit on climate change.Now that is behind them, I suspect that China will go straight back to “business as usual”. I would love to be proven wrong.
Dr Robin Russell-Jones