In this study, the learning of science outside the classroom is believe to be an added value to science learning as well as it offers students to interact with the environment. This study presents data obtained from two days' workshop on Lichen as Biological Indicator for Air Quality. The aim of the workshop is for the students to gain an understanding on various aspects on Lichens and its role as a biological indicator. Students are exposed to the following concepts and skills in the workshop: characteristics of algae, the concept of Lichen, causes of polluted air, the concept of quadrant, how to measure the frequency of Lichen, types of Lichen, determining the air quality index, factors determining the quality of air, the role of Lichen, the function of Lichen as a biological indicator and determining the level of air pollution. Four schools participated in the two day workshop whereby two schools were located in rural and urban areas respectively. A total of 125 students were given a pre-test on the concept of Lichen before the workshop followed by brief lecture sessions, hands-on and field work activities, presentation by students. At the end of the workshop, students were given a post-test. Overall, from the pre and post-test results, there is a significant difference in terms of students' performance from all the four schools, in knowledge and skills relating to Lichen and its role as a biological indicator in determining the quality of air.