Re: Solve this at the source
Yep, that last comment in the article was a complete clanker. It's far easier to inspect one power plant to ensure that its filters are effective and operational than it is on millions of vehicles which may have worn out, modified or non-existent (VW!) mechanisms, every one owned by a voter who might get pissy being informed that diesel exhaust is poisonous.
The UK has had times recently where no power comes from coal generation - it's clearly on the way out.