War and Urban-Industrial Air Pollution in the UK and the US
The Second World War stimulated an increase in industrial output and pollutant emissions. This often reduced improvements that had come about through smoke control policies in the interwar years. There were issues of patriotism and camouflage that could be invoked to relax regulations. Nevertheless, many clean air groups continued to advocate strongly for cleaner air and fuel economy. A shift from solid to liquid fuels and the industrial use of organic solvents and volatile feedstocks saw the appearance of secondary air pollution problems, the product of chemical reactions in a sun-lit atmosphere.