Runners in this year’s London Marathon escaped breathing badly polluted air as westerly winds cleared springtime smog just before the race start. Images of spring include blossom and fresh green growth, but it is often our most polluted time of year, and air pollution frequently reaches the top level on the UK government’s 10-point scale.
In spring 2014 Paris instigated odd/even number plate bans and David Cameron memorably tweeted that he was cancelling his run due to air pollution. That year, spring particle pollution caused an estimated 600 early deaths across England and Wales.
Springtime particle pollution happens when factory emissions and traffic exhaust mix in the air with ammonia from farms. Fertiliser for seedlings, slurry spread on fields and animals let out from their winter housing together cause more ammonia in spring than at any other time of year.
This April, particle pollution has mainly been less than level 7 on the government’s scale. The cold March weather has delayed farm schedules. In mid-April potatoes were not yet in the ground and wheat and barley sowing was weeks later than normal. This may delay the seasonal ammonia release and extend our spring particle pollution into May.
