Fireworks are fun but can reduce visibility

Scientists at the University of Birmingham have discovered that there is a sharp reduction in visibility caused by fireworks and bonfires on Guy Fawkes' night. They found that visibility was further decreased when the relative humidity was high. Using data taken over 13 years between 2000 and 2012 from 34 meteorological stations throughout the UK the scientists noted an average 25% reduction in visibility caused by atmospheric particulate matter from fireworks and bonfires. If the conditions are unfavourable then the visibility reduction can be much more severe; for example, visibility reductions of 64% were seen in Nottingham. Fireworks celebrations usually involve both bonfires and ground and air detonating fireworks. The particulate matter that is scattered after detonation is hygroscopic - its water content is dependent on the local 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.