The characteristic study of TSP, PM2.5∼10 and PM2.5 in the rural site of central Taiwan

The total suspended particle (TSP), PM2.5 similar to 10 (aerodynamic diameter less than 10 mu m) and PM2.5 concentration (aerodynamic diameter less than 2.5 mu m) 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, PM2.5 similar to 10 and PM2.5 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 PM2.5 similar to 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 PM2.5 similar to 10 in the rural site. The relationship between TSP and PM2.5 similar to 10 is TSP = 1.16PM(2.5 similar to 10) + 0.027 and TSP = 1.01PM(2.5 similar to 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 PM2.5 similar to 10 and PM2.5 is PM2.5 = 0.0005PM(2.5 similar to 10) + 0.019 and PM2.5 = 0.037PM(2.5 similar to 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)similar to 10, PM2.5 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 similar to 0.056 mu m and 3.16 similar to 5.62 mu m in the day period and appear between 0.017 similar to 0.031 mu m and 1.78 similar to 3.16 mu m 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. (C) 1999 Elsevier Science B.V. All rights reserved.