| 英文摘要 |
Ammonia is the only basic gas in the atmosphere. It is the primary neutralizing species of acidic substances in the atmosphere. Sulfuric acid and nitric acid are mainly neutralized with ammonia to form ammonium sulfate and ammonium nitrate which is turn into fine suspended particles. In order to investigate the degree of ammonia impact of PM2.5, our project focus on emissions of ammonia gas, on-site measurement of ammonia control efficiency, analysis of ammonia utilization rate of PM2.5 and the effect of ammonia reduction on the concentration of PM2.5.
Our project use AP-42 emmission factor to estimate emissions of ammonia gas in Taiwan in 2016 to 2018. It is estimated that the ammonia emissions are about 186,000 (metric tons per year) in the past three years. The most emission source is animal husbandry emissions, followed by waste water discharge and biological source discharge.
The ammonia control efficiency of the scrubber is mainly >99% by measurement of industrial process, and the ammonia component in the scrubber is ammonia sulfate, which can be reused by gas stripping ; The ammonai emission factor of pigs is 1.73 kg/animal-year by on-site measurement of farm .
The major chemical compositions for water soluble species in fine particles in 2018 are sulfate, ranging from 20% to 38%, followed by ammonium and nitrate, ranging 9%～13% and 6%～15%, respectively. It is necessary to pay more attention to control nitrogen oxides in southern Taiwan according to the analysis of ammonia utilization rate of PM2.5.
The results of CMAQ simulation for year 2016 with TEDS10 compliance with model evaluation guidelines. The effects for10%, 20% and 50% ammonia reduction on secondary PM2.5 simulated by CMAQ and the results show that the average concentration reductions of PM2.5, SO42-, NO3-and NH4+ are 1.7%, 0.25%, 0.98% and 0.42% for 10% , those of PM2.5, SO42-, NO3-and NH4+ are 3.6%, 0.5%, 2.1% and 0.9% for 20% and those of PM2.5, SO42-, NO3-and NH4+ were 10.9%, 1.5%, 6.3% and 2.7% for 50%. That is, the reduction for nitrate is more significant than that of sulfate. Similar results have shown in the measurement results, especially in northern Taiwan.
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