The Met Office and the Department of Health have been doing some partnership stuff around winter meteriological conditions and exascerbations of COPD, but not heard of anything about the volcanic ash and health effects-yet
I suspect low level inversion layers could kick things off in the UK. Anecdotally, low hazy stuff in the UK seems to equate with lots of people asking for blue inhalers. Haven't worked the science out yet
Long term? Probably equates to 1 week's of Manchester 1910 smog.