This kit enables students to study the effect of a common air pollutant, sulfur dioxide, on plants. Students grow marigold and squash from seed and expose half the one-week old seedlings to a constant, elevated concentration of sulfur dioxide (5 ppm). Over the course of the next several days, students compare the appearance of the exposed plants and the plants growing in clean air. Within hours, students can see damage to the exposed plants and within a few days the exposed plants die. An engaging activity with clear results.