what is the signal words use in the selection?



Chronic air pollution is expensive to the American public, costing us dearly in terms of both money and health. Air pollution causes buildings and automobiles to deteriorate. Our poisoned air damages crops. livestock, roads, and metals and forces huge cleaning bills for everything from dusty draperies to soot-blackened buildings (Griffin, 1972). It is especially in terms of health, however, that pollution hurts. It is estimated that breathing the air of New York City is the equivalent of smoking two packs of cigarettes a day.

​