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"The project is directed by the Tainan Municipal Environmental Protection Bureau (EPB), from May 5, 2017 to May 4, 2018, to do environmental monitoring of hazardous air pollutants (HAPs) in the ambient atmosphere. The analytical items include volatile organic compounds (VOCs), aldehydes and ketones, polycyclic aromatic hydrocarbon compounds (PAHs), acid-base gases, dioxin and heavy metals, and monitoring of PM2.5 emissions from stationary sources. The purpose of this project is to collect the concentration information of HAPs in Tainan City, and to establish PM2.5 emission fingerprint database and its emission coefficient according to the pipeline sampling results. This project uses the test data to propose specific control targets, recommended control strategies and expected improvement benefits for air quality improvement in Tainan City.
The results of the four seasons monitoring of HAPs are shown as the following. The VOCs in the air, the highest concentration measured in the first season (March 2017) of methanol, measured separately in Xinying elementary school (XYES) and Zhongshan middle school (ZSMS), 22.4 ppb and 28.2 ppb, the test value is much lower than the olfactory threshold (3300 ppb). The aldehyde and ketone compounds in the air measured the highest concentration in the second season (November 2017) of formaldehyde (0.0291 ppm) in ZSMS. The test value was slightly higher than the olfactory threshold (2.70×10-2 ppm). The PAHs in the air measured the highest concentration (3.2×10-4 mg/m3) of Naphthalene in the fourth quarter (February 2018) at the ZSMS. The test value is lower than the olfactory threshold (5.2 mg/m3). The acid-base gas in the air measured the highest concentration of ammonia (0.077 ppm) in the fourth quarter (May 2018) in XYES. The test value is still lower than the olfactory threshold (1.5 ppm).
The monitoring of ambient Dioxin showed the highest concentration occurred in the third quarter (February 2018), and the lowest in the first season (August 2017), and the displayed concentration may vary with the season. The concentration of PCDD/Fs in the atmosphere in summer is lower than that in winter, which is the same with the research results in literatures. The measured highest concentration of 0.083 pg I-TEQ/m3 occurred in the third quarter (February, 2018) at Xinshi elementary school. All the test values were all within the monitoring range of the national air quality monitoring station 0.001~0.255 pg I-TEQ/m3). The PCDD/Fs of each monitoring site accounted for a high proportion of PCDFs. The literature pointed out that if PCDD/Fs is generated by PAHs, PCDFs are dominant, and 2,3,4,7,8-pentachlorofuran (2,3,4,7,8-PeCDF) is the main characteristic species, which the sources were sintering plant, electric arc furnace and aluminum secondary smelting, etc., The ratio of PCDDs to PCDFs (PCDDs/PCDFs) of each station was less than 1, indicating that the Dioxin species mainly derived from the De Novo mechanism.
The results of heavy metal monitoring in the air showed that the elements are mainly aluminum (Al), barium (Ba), manganese (Mn), cobalt (Co) and other common crust elements. The concentration of heavy metal in PM2.5 showed no obvious seasonal change. Among them, the iron (Fe) concentration of 180 ng/m3 measured by Jianan University of Pharmacy in the first season (November 2017) was the highest. The highest concentration of heavy metal in PM10 was 980 ng/m3 aluminum (Al), measured at Longtian elementary school in the first season (November 2017). The results of other measurement of heavy metals of PM were far below the regulatory standards established by the domestic, world health organization (WHO) and the European Union.
The monitoring of the PM2.5 (FPM + CPM) in the discharge pipe found the concentration of four pipes were more than 20,000 μg/Nm3, which the industrial manufactory processes were Qu..." |