The project is directed by the Tainan Municipal Environmental Protection Bureau (TEPA) to investigate the concentration distribution of fine suspended particles (PM2.5) on the day of adverse air quality events over the years, to analyze the spatial and temporal distribution of PM2.5 concentration and its changing trend, to test the pipeline PM2.5 concentration and composition and then to establish of fingerprint characteristics of the emissions, to simulate the contribution of various types of primary PM2.5 emission sources to the perimeter in the city, and to do the cost-effectiveness analysis, providing TEPA a control strategy of PM2.5 emissions in the Tainan city.
According to the ambient PM2.5 data from the first quarter of 2009 to the third quarter of 2016, the proportion of the total number of high-concentration days (daily average concentration over 35μg/m3) in the four air quality monitoring stations was 26.8% in Tainan Station (TNS), 25.6% in Hsinyin Station (HYS), 24.0% in Shanghua Station (SHS), 23.6% in Annan Station (ANS). The total PM2.5 high-concentration days of the stations were as follows: TNS 1340 days, HYS 1281 days, SHS 1202 days, ANS 1179 days. The data show that there is a difference in PM2.5 concentration in the Tainan city due to its geographical location. The causes of the occurrence of bad air in the stations were compared. It is concluded that on the PM2.5 high-concentration days, particulate pollutants were not dominated by fine particles or coarse particles, which mean the main cause of particulate pollution could be the primary particulate.
During the implementation of the project from October 2015 to September 2016, the occurrence of high-level PM2.5 concentration (hourly concentration over 54μg/m3) days at four monitoring stations in Tainan was 152 days. The number of high-level concentrations (hours) in the four stations were HYS 787 hours, SHS 826 hours，ANS 785 hours, and TNS 690 hours. According to the same pollution source, the time periods were selected and totally 54 reports of pollution source analysis and control strategy have been written.
The frequency analysis chart of the PM2.5/PM10 ratio in the PM10 high concentration days shows that only the HYS is similar to the normal distribution; while in the SHS, the ANS, and the TNS, the contribution of PM2.5 to particulate pollutants is higher than that of PM10.
The Holland (1999) time series method is used to calculate the change trend of PM2.5 in the four air quality monitoring stations in Tainan city. And through the statistical analysis of the test, the PM2.5 concentration of four stations showed a decreasing trend of the annual rate of change -2.7% ~ -4.8%.
Total 30 PM2.5 manual monitoring stations were divided into seven air quality control areas (AQCA), Penghu, Jinmen and Matsu, and the PM2.5 concentration data from the year of 2013 to 2015 have been calculated. Monthly concentration of AQCAs show that, the PM2.5 concentration from December to February nest year are the highest period, and quarterly concentration showed that the highest concentrations are in the first quarter or the fourth quarter. Yearly average concentration showed that the highest value is found in the Yunlin, Chiayi, Tainan AQCA, and the lowest is in Hengchun station. To the date, the three highest PM2.5 concentration have been recorded are Douliou station 33.5 μg /m3, Chiayi Station 32.9 μg/m3, and Jinmen Station 31.6 μg/m3.
The project carried out nine pipeline PM2.5 concentration and composition analysis. The results show that, within filterable particulate matter (FPM) emission, sulfate and sodium ions are the majority to the anions and cations category, and aluminum and iron are majority to the heavy metals category. From the calculation of yearly emission discharge, the total suspended particulate matter (TSP) in the pipeline P006 to the M01 miscellaneous pulp manufacturing process of Taiwan Pulp ＆ Paper Corporation is 73.12 T/year and that of PM2.5 is 44.55 T / year, which both are the highest among the nine pipes. The TSP in the pipeline P509 to the M05 Vegetable Oil Processing Manufacturing Procedure of TTET Union Corporation is 0.11 T/year and that of PM2.5 is 0.07 T / year, which both are the lowest among the nine pipes.
In the spatial distribution of contribution of PM2.5 in Tainan city, the contribution of each point source in the industry is in the range of 0.34 ~ 9.05 μg/m3. The contribution of iron and steel industry is the highest, and the highest value appears in Yongkang area (10.27 μg/m3), which is supposed to be due to the maximum contribution of the steel industry. The contribution of the highest value of the line source in each screening industry ranged from 0.43 ~ 7.08 μg/m3, with the contribution of the diesel truck being the highest and the highest regional value at the junction of the Eastern, North and Yongkang. The contribution of the highest value of area source was 0.056 ~ 21.84 μg/m3, the contribution of pavement was the highest, and the highest regional value was occurred at the junction of the Eastern, North and Yongkang. The areas with high values of area sources are similar to that of line sources. The primary source of PM2.5 in the point source, line source, area source and other sources of pollution, except the first and the second period of agricultural combustion of a rice has its seasonal time period, the discharge of other sources of PM2.5 pollution is no significant seasonal changes within a year.
In this study, the LINGO linear programming is used to simulated the cost related to the reduction of the PM2.5 emission of 26 pollution sources. Six control scenarios will be simulated, i.e., 5%, 10%, 15%, 16%, 17% and 17.7%. The total cost will be 4.18 million NT dollars in the context of a reduction of 5%. The total cost will be 56.57 million NT dollars in the context of a reduction of 10%. The total cost will be 209 million NT dollars in the context of a reduction of 15%. The total cost will be 426 billion NT dollars in the context of a reduction of 16%. The total cost will be 1190 billion NT dollars in the context of a reduction of 17%. However, once the regulatory ratio is raised to 17.7%, the total cost is increased to 78880 billion NT dollars. The reason is that in the 17.7% reduction scenario, the proportion of PM2.5 in various industries has reached or nearly reached the maximum control efficiency of the industry's control measures.
The ambient Dioxin has been tested at the HYS and TNS. The results showed that the concentration of dioxin was no significant change at the HYS and TNS, comparing the results of ambient Dioxin concentration at these two stations in the past. The results of the analysis of ambient heavy metals in the HYS are quite different from those of previous years. The possible reason of the differences could be due that ambient heavy metals were detected in PM10 in the past research by EPA, and thus those were detected in PM2.5 in this project.
The achievements of this project are to show the spatial and temporal distribution of PM2.5 and high pollution potential areas in the city to facilitate the development of appropriate control strategies. The establishment of the city's main pollution sources of TSP and PM2.5 emissions from fingerprint databases, emission factors and emissions. And the results of the project provide the Tainan EPA with the basis for pollution abatement and control strategies by developing the best cost-effectiveness control sequence for the city's indigenous PM2.5 emission sources.
