The characteristic study of TSP, PM 2.5∼10 and PM 2.5 in the rural site of central Taiwan

Abstract

The total suspended particle (TSP), PM 2.5∼10 (aerodynamic diameter less than 10 μm) and PM 2.5 concentration (aerodynamic diameter less than 2.5 μm) concentrations were sampled by PS-1 and Universal sampler on the roof (25 m) of the Medical and Engineering Building in the campus of Hungkuang Institute of Technology (HKIT) which is located at a height of 500 m on Da Du Mountain. The results indicated that average TSP, PM 2.5∼10 and PM 2.5 concentrations are 0.42, 0.34 and 0.019 mg/m 3 in the day time, respectively and are 0.32, 0.26 and 0.017 mg/m 3 in the night time, respectively. The ratios of PM 2.5∼10/TSP were from 76% to 85% and from 50% to 91% for day and night period, respectively. It indicated that the major composition in the total suspended particles was PM 2.5∼10 in the rural site. The relationship between TSP and PM 2.5∼10 is TSP=1.16PM 2.5∼10+0.027 and TSP=1.01PM 2.5∼10+0.058 in the day and night time, respectively. The correlation coefficient (R 2) is 0.98 and 0.97 for day and night period, respectively. The relationship between PM 2.5∼10 and PM 2.5 is PM 2.5=0.0005PM 2.5∼10+0.019 and PM 2.5=0.037PM 2.5∼10+0.0076 in the day and night period, respectively. The correlation coefficient (R 2) is 3E-5 and 0.67 for day and night period, respectively. The relationships between TSP, PM 2.5∼10, PM 2.5 particle concentrations and wind speed (R 2) in the day time are 0.71, 0.64, 0.43, respectively and are 0.83, 0.79, 0.57, respectively in the night time. The proposed reasons are that there are more activities caused by people (students) and natural living animals which absorbed some of the particles during the day time. Thus, the correlation coefficients for the night time are better than those of day time. The particle size distributions are both bimodel in the day and night time. The major peaks in the day time appear in the particle diameter between 0.031∼0.056 μm and 3.16∼5.62 μm in the day period and appear between 0.017∼0.031 μm and 1.78∼3.16 μm in the night period. The results indicate that the particle size distribution in the day time tends to be of larger particle size mode than the night time.