This forum is about wrong numbers in science, politics and the media. It respects good science and good English.
Well ... the LACK of data.
Improved data is needed to better understand the personal health impacts of air pollution exposure, according to King’s College London professor
Speaking just before Professor Kelly at the conference was Ricardo-AEA consultant to Defra, Brian Stacey, who said that the greater uncertainties in modelled compared to measured air quality could “cause problems with public understanding” of pollution levels.
Add to this the fact they are very bad at saying what people die from.
A Scripps Howard News Service study of 4.9 million cause-of-death records for 2005 and 2006 from the Centers for Disease Control and Prevention revealed a disturbing conclusion:
Medical experts think about 30 percent of the death diagnoses were either incorrect, fraudulent or just somebody’s wild guess.
That means our knowledge of what’s killing Americans — and more than 2.4 million of us die each year — is not terribly accurate, which greatly complicates the cause of prevention
I made an interesting discovery about public health researchers last month. I've always suspected that at least some of them are activists, a bit like the situation with climate scientists and environmental scientists. However a blog post I noticed on the Royal Society's "In Verba" science policy blog included this candid observation from Richard Horton, editor of "The Lancet" medical journal:
"Should there be a separation between scientists and campaigners? Is such a separation possible? Richard Horton pointed out that for a public health researcher, not being an activist is the exception."
Given the above you can pretty much assume that Frank Kelly, Professor of Environmental Health at King's College, London, is very likely to be an anti-pollution activist. So when he talks about the personal health impacts of air pollution exposure requiring improved data, I wouldn't interpret this as possibly meaning that existing pollution regulations may need to be toned down in the light of more accurate data. His aim will be to make pollution regulations more stringent.