smog

"The store's cash register recorded the total sales for the day. "

"The noisy construction outside the church was a pollution of the peaceful atmosphere, distracting everyone from the service. "

"He enunciated every syllable clearly."

"The mixture of flour and water was carefully stirred to make the dough. "

"Particulates in engine oil can abrade moving parts."

"Check the oil in your car once a month."

"We spent the weekend hiking in the mountains."

"the result of a course of action;  the result of a mathematical operation"

"The fumes from the factory were noxious and made it hard to breathe. "

"My father's truck is a reliable vehicle for transporting the family to the park. "

"Before dinner, I finished my homework. "

"the emission was mostly blood"