Answer the following question given this paragraph: 

Figure 12.7 Statues made from carbonate compounds such as limestone and marble typically weather slowly over time due to the actions of water, and thermal expansion and contraction. However, pollutants like sulfur dioxide can accelerate weathering. As the concentration of air pollutants increases, deterioration of limestone occurs more rapidly. (credit: James P Fisher III).


Q: Deterioration of limestone occurs more rapidly as the concentration of what increases?

 Choices:

- ground pollutants

- water pollutants

- ocean pollutants

- air pollutants

A:
air pollutants
