Your 2018 RAM diesel engine uses a special system to help clean the exhaust emissions. Diesel exhaust fluid (DEF) is injected into the diesel exhaust system to help remove nitrous oxides (NOx) and particulate matter (PM). The DEF tank holds the DEF fluid much as a fuel tank holds fuel for diesels.
Read more about the dangers of diesel exhaust fumes – https://ehlinelaw.com/blog/many-dangers-diesel-exhaust-fumes
