University of Birmingham study warns of ‘sharp reduction’ in visibility caused by fireworks and bonfires
There is a “sharp reductionâ€? in visibility caused by air pollution from fireworks and bonfires on and around Guy Fawkes night (November 5), University of Birmingham scientists warn – raising concerns over road safety.
Using data taken over 13 years between 2000 and 2012 from 34 meteorological stations throughout the UK, the scientists’ study noted an average 25% reduction in visibility caused by atmospheric particulate matter from fireworks and bonfires.
And, if the conditions are unfavourable – such as when relative humidity is high – then the visibility reduction can be much more severe, with the study finding visibility reductions of 64% in Nottingham.
The visibility reducing effect of the extra particulate matter loading in the atmosphere can also last up to two days after the fireworks event, according to the study, which is published in the November 2015 issue of Royal Meteorological Society’s journal Weather.
The study – ‘Remember, remember the 5th November: gunpowder, particles and smog’ – found that particulate matter which is scattered after detonation of a firework is ‘hygroscopic’, meaning that its water content is dependent on the relative humidity.
As the humidity increases so does the water content of the particulate matter, changing the average size and composition of each particle, which leads to the particle being able to scatter light more effectively and hence reduce visibility.
The authors of the study said their findings raise concerns regarding motorist and pedestrian safety on bonfire night due to the high change of poorer visibility.
Dr Francis Pope, lead author from the University of Birmingham’s School of Geography, Earth and Environmental Sciences, said: “Guy Fawkes’ night, and fireworks in general, are attended and much enjoyed by me and many others. Unfortunately, these events can affect short term air quality and lead to significant reductions in visibility. We hope that our work will lead to improved forecasting of visibility degradation.
“If forecasts suggest that planned displays will coincide with conditions likely to exacerbate poor visibility then organisers and local authorities should be prepared to issue poor visibility warnings in advance. This precautionary measure could prevent unnecessary accidents.â€?
– Royal Meteorological Society article: ‘Remember, remember the 5th November: gunpowder, particles and smog’