| 英文摘要 |
This project is aimed at the monitoring of PM2.5, heavy metals, and water-soluble anions and cations in Jin-cheng junior high school in Kinmen from November 16, 2018 to January 15, 2019. Through the meteorological factors(wind speed, and wind direction, etc.) and concentration trends are used to assess the possible sources of pollutions. The summary of the results of this project is as follows:
1. Complete continuous monitoring of fine particle(PM2.5) for 53.45 days.
The on-line particle mass concentration analyzer (EBAM), which is affected by humidity, the trend of PM2.5 concentration is consistent with EPA station, but it is easy to have extreme values. After screening RH>80%, the data quality is obviously improved. If there are similar applications in the future, should pay attention to the possible interference of relative humidity. You can refer to this screening principle.
2. Complete continuous monitoring of heavy metals in fine particle for 46.16 days.
The analysis results show that the daily average value of PM10 meets the regulatory standards, and PM2.5 exceeds the standard for 7 days. The concentrations of heavy metal species have relatively high average concentrations of potassium, iron, zinc and calcium in the crust elements, which are 476.3, 169.3, 105.5 and 92.5 ng/m3, respectively. The lead, manganese and titanium are second, 21.7, 13.5 and 12.5 ng/m3 ,respectively. According to the wind and rose diagram of the concentration and wind direction, most of the heavy metal species have a high concentration of wind direction, mainly southwest and northeast. According to the statistical results of wind direction, and the main prevailing wind is the northeast wind. The frequency of occurrence is 33.98% of the effective wind direction. It shows that during the monitoring period, the main prevailing wind direction in the local area is the northeasterly wind, and the total angle from the north-north east wind to the northeast easterly wind (the total wind direction in this range is 68.93%) is also the main wind direction trend.
3. Complete continuous monitoring of anion, cations, and main ion precursor gas in fine particle for 54.70 days.
In terms of average concentration, the gas has higher NH3 concentration of 2.67 ppb, followed by SO2 1.07 ppb and a minimum concentration of HCl 0.16 ppb. The water-soluble cation is higher with NH4+ 2.50 μg/m3 and lower with K+ 0.13 μg/m3. The water-soluble anion is higher with SO42- 6.41 μg/m3 and lower with NO2- 0.39 μg/m3. Among them, the proportion of water-soluble anion and cation in PM2.5 is higher with SO42- 28.40%, followed by NO3- 20.70%. It can be known that the aerosol component in atmosphere occupies a certain proportion in PM2.5.
Since SOR>0.25 and NOR>0.10, it means that SO42- and NO3- are oxidized by local pollutants and may be oxidized by long-range transport pollutants. It also indicates that the oxidation reaction in this area is strong and has more derivative PM2.5. According to the polar plot, most of the metal elements and the dominant anion and cation(SO42-, NH4+, and NO3-) have the same pollution source type as PM2.5, and the high concentration mainly occurs at low wind speeds from the southwestern west.
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