| 英文摘要 |
This project is a continuum of two previous air quality monitoring projects conducted at ○○ primary school and ○○ junior high school in 2009. The objectives of this project are to set up two air quality monitoring stations at ○○ primary school and ○○ junior high school for continuously monitoring the air quality of these schools, to provide real-time air pollutants and meteorological data to the regulatory personnel when an odor complaint is filed by teachers and students from these two schools, and to help analyze the root cause of the odor nuisance and the potential source of the odorous pollutants.
The OP-FTIR monitoring station of ○○ Primary School started collecting first infrared spectrum (data) in April 9, 2010 till March 31, 2011. A total of 356-day (8,544 hours) of OP-FTIR monitoring has been operated. A grand total of 102,588 valid spectra out of 110,633 spectra were collected and analyzed. The data collection effectiveness of ○○ Primary School OP-FTIR monitoring station is 92.73%. The OP-FTIR monitoring station of ○○ Junior High School started collecting data from July 1, 2010 till March 31, 2011. A total of 72,938 valid data out of 78,292 spectra were collected and analyzed in a period of 274-day of monitoring. The collection effectiveness of ○○ Junior High School OP-FTIR monitoring station is 93.16%.
Excluding calm wind (wind speed<0.5 m/sec) condition, northerly wind (covering NW, N and NE) prevailed in colder months from October till next March, while the southerly wind predominated during the hot months from April to September. The average wind speed of 0.5~2.0 m/sec covered nearly 80% of the monitoring period. Nevertheless, the wind speed was higher during the typhoon months of August and September.
Thirty-eight anthropogenic pollutants were identified and quantified from 102,588 spectra collected from ○○ Primary School OP-FTIR monitoring station. These air pollutants were ammonia, methanol, ethylene, ethyl acetate, ethanol, butane, 2-methyl pentane, chlorodifluoromethane (R-22), N,N-dimethyl formamide (DMF), cyclohexane, acetylene, propylene, propylene glycol monomethyl ether (PGME), sulfur hexafluoride (SF6), chloroform, carbon tetrachloride, 1,1,1,2-tetrafluoroethane (R-134a), vinyl chloride, vinyl acetate, trifluoromethane, trichlorofluoromethane (R-11), toluene, sulfur dioxide (SO2), n-pentane, methyl methacrylate (MMA), methyl formate, isopropanol, ethylene oxide, dimethyl ether, dichloromethane, bromotrifluoromethane, dichlorodifluoromethane (R-12), acrylonitrile, acetone, 2-butanone, 1,3-butadiene, 1,1-dichloro-1-fluoroethane and 1,1,2,2-tetraflurorethane (R-134b). In addition, methylal and paraformaldehyde were also identified but no quantitative spectrum available. Seven out of 38 pollutants were detected in each month’s monitoring. They are ammonia, methanol, ethylene, ethyl acetate, chlorodifluoromethane, acetylene, and ethanol. Ammonia, methanol, ethyl acetate, and ethylene were the only pollutants with detected frequency higher than 1.0%, which indicates that these compounds were the major anthropogenic air pollutants in the atmosphere of ○○ Primary School.
Fifty anthropogenic air pollutants were detected and analyzed both qualitatively and quantitatively from ○○ Junior High School OP-FTIR monitoring station. They are ammonia, methanol, ethanol, ethyl acetate, SO2, R-22, ethylene, vinyl acetate, acetylene, acetone, 2-butanone, trifluoromethane, R-11, propylene, PGME, isoprene, hydrogen chloride, ethylene oxide, vinyl chloride, SF6, isobutanol, R-12, 2-methyl pentane, 1,3-butadiene, trifluoroethane, toluene, tetrahydrofuran, propane, propylene glycol monomethyl ether acetate (PGMEA), n-butyl acetate, DMF, MMA, methyl Acrylate, isopropyl benzene, isopropanol, gasoline, formaldehyde, ethyl Acrylate, dimethyl ether, dichloromethane, cyclohexane, chloroform, carbon tetrachloride, butane, bromotrifluoromethane, acrylonitrile, acetic acid, 1,1-dichloro-1-fluoroethane, R-134b, and R-134a. Methylal was also identified in ○○ Junior High School OP-FTIR monitoring station. Seven out of 38 pollutants were detected in each month’s monitoring. They are ammonia, methanol, ethyl acetate, ethanol, ethylene, R-22, PGME, R-11, R-12, and SF6. Ammonia, methanol, ethyl acetate, ethylene, acetylene, R-22 and vinyl acetate were the only pollutants with detected frequency higher than 1.0%, which indicates that these compounds were the major anthropogenic air pollutants in the atmosphere of ○○ Junior High School.
During 356 days of monitoring in ○○ Primary School, the concentrations of ammonia, EO, vinyl chloride and acrylonitrile were found to be over their existing ambient standards. There are 3 measurements of ammonia were found to be over its ambient standard of 1000 ppb. High concentration of ammonia is coming from an ammonium hydroxide manufacturer located in northwesterly direction of the school. Ethylene oxide is the contribution of a medical equipment disinfection company located in NNE of the school. Vinyl chloride was detected only in June when the southerly wind prevailed. There were only 4 measurements of concentration higher than 200 ppb of ambient standard. There are two emission sources of vinyl chloride located in Lin-yuan industrial park which is about 6 kilometers down south of school. Acrylonitrile has a ambient standard of 40 ppb. There were only three measurements of acrylonitrile with concentration greater than 40 ppb from two OP-FTIR monitoring stations. The potential source of the handful detected acrylonitrile was possibly contributed from the pressure relief valve of the driving-by tanker trucks carrying acrylonitrile.
Ethyl acetate, MMA and toluene were three odorous pollutants detected in ○○ Primary School. The majority of Ethyl acetate and toluene were coming from a chemical container cleaning company located in northeast direction of school. Part of ethyl acetate was the contribution of the commercial sign company located 100 meters south of the campus during its paint-spray operation. MMA was possibly coming from the pressure relief valve of the driving-by tanker trucks carrying MMA.
Ethyl acetate, toluene, acetic acid, ethyl Acrylate, methyl Acrylate, MMA and n-butyl acetate were found with measured concentrations higher than their odor thresholds in ○○ Junior High School. However, there were only few measurements of these odorous pollutants with detected concentrations greater than their odor thresholds. The commercial sign company next to south boundary of school campus contributed most of ethyl acetate, toluene, and n-butyl acetate during its spraying operation. Acetic acid was also coming from the pressure relief valve of the driving-by tanker trucks carrying acetic acid, a small portion of acetic acid was coming from A company. Methyl acrylate and ethyl acrylate were used as organic solvents in manufacturing herbicide and pesticide. These two odorous pollutants detected in ○○ Junior High School were the residues of herbicide from local farmers.
In order to further verify emission sources of major pollutants (both hazardous and odorous), additional investigation program named source-tracking program using OP-FTIR, CC-FTIR and/or bag-GC/MS was executed. A total of 1100 hours of FTIR monitoring (excluding number of GC/MS samples) at 12 factories and areas within Da-Fa industrial park and its surrounding area. This is 125% more of the investigation time required by the project. The results verified the major emission sources of ethylene oxide, ammonia, ethyl acetate, toluene, ethanol, methanol, and 2-butanone. The upwind/downwind OP-FTIR simultaneous measurement from January 31 to February 9, 2011 conducted in the northwest of two schools. The results indicates that ethylene, vinyl acetate, DMF, and part of 1,3-butadiene were coming from sources located upward of the upwind beam. This concludes that the petrochemical industrial park located 20 kilometers northwesterly of ○○ area is the only emission source of these pollutants.
|