Evaluation of Air Pollution Tolerance Index of Certain Trees Growing in Two Areas in Brack Al-Shatti, Libya

Abstract

Air pollution is considered one of the significant environmental issues, and its effects extend beyond humans to other living organisms, including plants. Air pollutants impact the activity and growth of plants by affecting several chemical and physical properties, such as the tolerance index. Therefore, this study aimed to investigate the Air Pollution Tolerance Index (APTI) of several tree species at two locations in the municipality of Brack Al-Shatii, namely the university site and the project site, which included palm, tamarisk, olive, and acacia trees. Four properties were assessed: pH, relative water content, total chlorophyll concentration, and ascorbic acid concentration. The results showed that the average pH value of the leaf extracts from the studied trees was 5.853±0.245, while the average relative water content in the study area was 76.813±13.734%. The results also indicated that the average chlorophyll concentration in the trees in the study area was 0.422±0.0957 mg/L, while the average ascorbic acid concentration in the study area was 39.915±20.962 mg/L. The findings revealed that the most tolerant tree species at both sites was the palm tree, with an APTI value of 31.55 at the university site, which increased to 64.12 at the project site. In contrast, the red river gum tree was sensitive to air pollutants, with an APTI value of 16.49 at the first site and 15.84 at the second site. Meanwhile, the olive tree exhibited moderate tolerance to air pollutants, with an APTI value of 17.03 at the first site and 15.63 at the second site.