IPA: /ˈsʌlfərəsli/
KK: /ˈsʌlfərəsli/
In a manner that relates to or resembles sulfur, often associated with a strong, unpleasant smell or atmosphere.
The air was sulfurously thick, making it hard to breathe.
Sulfurously → It is formed from "sulfur" (from Latin *sulfur*, meaning the element sulfur) and the suffix "-ous" (meaning full of or characterized by). The word "sulfurously" means characterized by or full of sulfur, often referring to a strong, pungent smell associated with sulfur compounds.
Think of the element 'sulfur' which is known for its strong smell, and remember that 'sulfurously' describes something that is full of that sulfur scent.