Air Quality Expert Group, Nitrogen Dioxide in the United Kingdom, 2004, p. 3 ([Internet, 2021-10-29](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwij8fyn2u_zAhWbhP0HHU2gDcIQFnoECBoQAQ&url=https%3A%2F%2Fuk-air.defra.gov.uk%2Flibrary%2Fassets%2Fdocuments%2Freports%2Faqeg%2Fnitrogen_dioxide_in_the_UK-summary.pdf&usg=AOvVaw3D4izXHaw0tIbVJO5yBjUj))