Analysis of Reduction Strategies for Air Pollutants Discharged from Emission Sources and their Impact on the Seoul Metropolitan Area
Abstract
The Korean government enacted the “Special Law for Improving Air Quality of Metropolitan Area” in 2003. According to this plan, Korean government plan to lower the concentrations of PM10 and NOx to 40 μg/m3 and 22 ppb, respectively, by 2014. In this study, we analyze emission reduction strategies to lower their concentration. Emission reduction for the supply of mass energy and regenerative energy are compared with several scenarios. According to the results, 713 t/y of NOx and 165 t/y of PM10 will be reduced by enhancing the number of households supplied by local heating and air conditioning. And also 5 t/y of PM10 and 312 t/y of NOx will be reduced by replacing conventional energy with solar energy by 2014.
Keywords:
Area source, Emission, Reduction, Mass energy, Regenerative energy, NOx, PM101. INTRODUCTION
Korea has kept a high economic growth policy since the 1970’s and joined the OECD group as a result. However, air quality has reached a serious level with the increase in industrial development. The Korean government has tried eagerly to improve the air pollution situation using various environmental policies such as fuel regulations and stronger emission standards. Concentrations of TSP, SO2, and Pb were noticeably reduced in ambient air after the policies were put into effect. However, concentrations of PM10, NOx and O3 were not improved (Konkuk University, 2006). Concentrations of PM10 and NOx (Fig. 1) were 69 μg/m3 and 38 ppb, respectively, in the metropolitan area in 2001. This was equivalent to 1.9-3.6 times the value of OECD countries.
It is estimated that 1,940 persons died in 2000 from PM10-related illnesses in Seoul city. The Korean government enacted the “Special Law for Improving Air Quality of Metropolitan Area” in 2003 and plans to lower the concentrations of PM10 and NOx to 40 μg/m3 and 22 ppb, respectively, by 2014. Emissions from point, area and line sources must be reduced to accomplish this goal (MOE, 2005).
In this study, we discuss reduction strategies of emissions, especially from area sources. We evaluated the impact of these reductions. A proper reduction strategy can be established only on the basis of studies such as this.
2. EMISSION REDUCTION STRATEGY
Maximum permissible emissions were set to reach the target concentrations by 2014. Emission reduction amounts are given in Table 1. 24,603 t/y of NOx and 436 t/y of PM10 must be reduced by 2014. Initially, the status of emissions was studied to evaluate reduction potential. Then several alternative reduction strategies were discussed.
2. 1 Estimation of Emissions from Area Source
Our target area was composed of Seoul city, Incheon city and a part of Gyonggi-Do province. Contribution rates of emission sources to air quality in the metropolitan area are described in Fig. 2. Emissions from area sources are estimated in Table 1. According to Fig. 2 and Table 1, emissions are affected mainly by line and area sources. This study specifically discusses how to reduce emissions from area sources. According to Table 1, 58% of NOx emissions and 48% of PM10 emissions need to be reduced by 2014. Maximum permissible emissions for 2014 are given in Table 2.
2. 2 Plan to Reduce Emissions
The Korean government has made plans to reduce emissions from area sources. The effectiveness of the plans is currently unknown. Only if the plan is effectively executed will the target emission reductions be obtained. Therefore, several scenarios of reduction strategies were compared to see whether they will reach the reduction goal in the target year.
Several measures to reduce emissions from area sources have been already implemented. These include fuel regulation, promotion of supplied local heating and air conditioning, strengthened NOx management and management of energy demand.
Table 2 shows maximum permissible emissions to reach target concentrations of air quality by 2014. According to Table 2, by 2014, 24,603 t/y of NOx and 436 t/y of PM10 have to be reduced using these measures (KEI, 2004). Several measures for area sources are listed in Table 3 (KEMCO, 2005). Supplying local heating and air conditioning and replacement of conventional energy with solar energy were considered the main reduction measures in this study.
Several scenarios for supplying local heating and air conditioning and enhancement of solar energy usage were considered to compare the reduction effects of these measures.
How supply rate is determined and enhanced is important. We hypothesized three scenarios: Scenario 1: supply 105,000 households per year; Scenario 2: supply 92,000 households per year; Scenario 3: supply 85,000 households per year (see Table 4).
We considered only solar energy in the regenerative energy category. The supply rate of solar energy is 100,000 households per year from 2001 to 2010 on the basis of the 2nd national energy master plan (MOCIE, 2002). But the rate is 100,000 households and 30,000 commercial facilities on the basis of the 2nd technical development and supply & usage plan for regenerative energy. We hypothesized four scenarios (Table 4) on the basis of these two plans.
3. EVALUATION OF IMPACT OF REDUCTION MEASURES
Emission reduction amounts were summarized for each reduction measure. Their impacts were divided into two parts: mass energy and regenerative energy.
3. 1 Mass Energy
We hypothesized three scenarios for reducing emissions (see Table 3). Emissions reduction for the metropolitan areas is most important because the abovementioned reduction measures are being implemented to improve the air quality of the metropolitan area. It was necessary to determine the percent replacement ratio of the conventional system with local heating and air-conditioning (below LHA) to estimate reduction amounts. The national supply plan is not categorized for each local autonomous entity, nor is it for the metropolitan area. Therefore, the concept of area ratio (whole country area versus target area (designated by the special law)) was introduced to calculate the replacement ratio and reduction amounts. We divided the total number of households supplied by local heating and air conditioning by the number of households supplied in the metropolitan area and the number supplied in other areas on the basis of this concept. Results are given in Table 6 and Fig. 3. Replacement ratios ranged from 21.1% to 23.3%. Reduction amounts of NOx were 1,713 t/y, 1,504 t/y and 1,408 t/y for scenarios A, B and C in 2014, respectively. PM10 was reduced by 165 t/y, 145 t/y and 136 t/y for scenarios A, B and C in 2014, respectively.
3. 2 Regenerative Energy
Four scenarios were compared for regenerative energy (see Table 5). There are many types of regenerative energy, but only reductions using solar energy were discussed in this paper. Replacement ratios for solar energy and reduction amounts were computed by Equation (1).
(1) |
where ERf=amount of emission reduction in 2014, p (replacement ratio)=(number of households supplied by solar energy)/(number of total households in metropolitan area)×100,
ERi=emission amount in 2014.
Results are described in Table 7 and Fig. 4. It was estimated that 204-312 t/y of NOx and 3-5 t/y of PM10 will be reduced by 2014. If the replacement ratio increases 50 1.0%, the amount of NOx and PM10 will be reduced to 400.5 t/y and 6.2 t/y, respectively.
4. CONCLUSION
In the present study, emission reduction strategies and their impacts were analyzed and reduction scenarios of emissions were compared. Results were summarized as follows:
- (1) Emissions were reduced by enhancing the number of households supplied by local heating and air conditioning. Reduction amounts were estimated at 1,713 t/y of NOx and 165 t/y of PM10 by 2014.
- (2) A total of 5 t/y of PM10 and 312 t/y of NOx will be reduced by replacing conventional energy with solar energy by 2014. The emission reductions will be larger in the future, because the use of renewable energy, such as geo-thermal energy and wind energy, will continue to be developed
References
- KEI, (2004), Development of Total emission management system in metropolitan areas, p491-516.
- KEMCO, (2005), Data Book of Mass Energy Supply Plan, p26-37.
- Konkuk University, (2006), Analysis of Effects to improve Air Quality and their post-management Plan by Korean Air Quality Management Policy, 1-4, p41-113.
- MOCIE, (2002), Master Plan for the Enlargement to use and supply with new and renewable energy, p112-118.
- MOE, (2005), Master Plan for Air Quality Management in Metropolitan Areas, p33-55.