Air Purifier in London Deep Shelter
Here we see an A.R.P. attendant using an air purifier to clean the air in one of the five of London's eight deep air raid shelters that were put into use during the V-1 offensive of 1944-45. Each could shelter 8,000 people. They were built as long tunnels in the hope that they could later be converted into part of new Underground train lines, although in the end that didn't happen.