Instructions: Choose One Answer from Each Pair of Selections

Q50: Pollution is most severe in urban areas

Q51: Which condition typically contributes to major air

Q52: Particles with diameters less than one micrometer

Q53: Describe how the use of a tall

Q54: Which toxic gas is an important component

Q56: Carbon monoxide (CO) has a strong pungent

Q57: Erosion of many limestone buildings, fountains, and

Q58: Air pollutants are _ airborne substances.<br>A) exclusively

Q59: Instructions: Choose one answer from each pair

Q60: Polar stratospheric clouds play a role in