“The adverse effects on health of particulate matter (PM) are especially well documented. There is no evidence of a safe level of exposure or a threshold below which no adverse health effects occur.”

From 3 days ago.

“….on the health risks, it’s very very clear – especially for particulates – that there’s no healthy exposure level and also that the EU limits are higher than they should be to protect health adequately, so anything the road causes on top of these is pretty much guaranteed to be harmful to people exposed.”

Still, it might win the LibDems a few votes, so that’s all right then!