Optical absorption characteristics of brown carbon aerosols during the KORUS-AQ campaign at an urban site

Park, Seungshik,Yu, Geun-Hye,Lee, Sangil Elsevier 2018 Atmospheric research Vol.203 No.-

<P><B>Abstract</B></P> <P>This study investigates the absorption characteristics of brown carbon (BrC) obtained from water and methanol extracts of fine particulate matter measured at an urban site in Gwangju, Korea during the KOREA U.S. – Air Quality campaign (May 2–June 11, 2016). The measurement period was classified into two intervals: biomass burning (BB) and non-BB periods. During the non-BB period, water-soluble organic carbon (WSOC) and humic-like substances (HULIS) primarily resulted from secondary organic aerosol (SOA) formation and primary vehicle emissions. Water-soluble organic aerosols during the BB period, meanwhile, were closely related to SOA formation and regionally transported BB emissions.</P> <P>The light absorption coefficient measured at 365nm (b<SUB>abs,365</SUB>) by methanol extracts was 2.6 and 6.1 times higher than the coefficients from the water and HULIS extracts, respectively, indicating the importance of BrC absorption by water-insoluble organic carbon. This was demonstrated by a good correlation between the water-insoluble BrC absorption and the elemental carbon concentration. A comparison of b<SUB>abs,365</SUB> between the methanol- and water-extracted BrC indicated that water-insoluble BrC accounted for approximately 61% (33–86%) of the total BrC absorption. The contributions of SOA, primary BB emissions, and traffic emissions to the water extract b<SUB>abs,365</SUB> were estimated using a stepwise multiple linear regression (MLR) analysis and found to be 1.17±0.55, 0.65±0.62, and 0.25±0.09Mm<SUP>−1</SUP>, respectively, accounting for 59.6, 26.1, and 14.3% of the absorption coefficient by the water-soluble BrC. Further, it was determined that the contribution of the BB emissions to the water-soluble BrC absorption was approximately two times higher in the BB period than in the non-BB period.</P> <P>The average absorption Ångstrӧm exponent was 4.8±0.3, 5.3±0.7, and 6.8±0.8 for the methanol, water, and HULIS extracts, respectively. The average mass absorption efficiency (MAE<SUB>365</SUB>) of methanol extracted BrC was 1.3±0.4m<SUP>2</SUP>/g·C. Water- and HULIS-extracted BrC had a MAE<SUB>365</SUB> of 1.0±0.3 and 0.8±0.3m<SUP>2</SUP>/g·C, respectively. These results suggest that methanol-extracted BrC could provide a better estimation of BrC absorption compared to WSOC and HULIS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Heterogeneous processes were a dominant contributor to NO<SUB>3</SUB> <SUP>-</SUP> and SO<SUB>4</SUB> <SUP>2-</SUP> formation during the non-biomass burning (BB) period. </LI> <LI> Regional transport and high O<SUB>3</SUB> could be important factors for the enhanced NO<SUB>3</SUB> <SUP>-</SUP> and SO<SUB>4</SUB> <SUP>2-</SUP> during the BB period. </LI> <LI> Water-soluble organic aerosols were associated with SOA, regionally transported BB, and traffic emissions. </LI> <LI> About 60% of total brown carbon (BrC) absorption comes from water-insoluble BrC. </LI> <LI> Contribution of BB source to water-soluble BrC absorption was two times higher in the BB period than in the non-BB period. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

환경·경제 통합분석을 위한 환경가치 종합연구 : 부문별 영향평가 및 가치추정

안소은,이홍림,박윤선,홍현정,서양원,김충기,한선영,정다운 한국환경연구원 2021 사업보고서 Vol.2021 No.-

Ⅰ. 탄소흡수·저장 통합분석 사례연구 1. 개요 및 분석범위 설정 □ 2050년 탄소중립 사회로의 성공적 전환을 위한 선제 작업으로, 생태계의 탄소흡수·저장량과 가치에 대한 과학적·객관적 평가가 가능한 탄소흡수·저장 통합분석 툴킷을 구축하였음 ○ 2016년 연구에서는 환경영향 정량화와 단위가치 연계를 위한 툴킷 기반을 구축하였고, 2021년 연구에서는 개선·안정화시켜 툴킷 구축을 완료하였음 - 올해 연구에서는 2016년 연구에서 설정한 생태계 유형, 생태계 탄소흡수·저장계수 등을 적용하여 2019년 당시의 생태계 탄소흡수·저장 기능을 평가·갱신하고 그 경제적 가치를 추정하여 탄소중립을 위한 정책 의사결정을 지원하고자 하였음 2. 영향평가 □ 2019년 기준, 생태계의 탄소저장량은 9억 5,000만 톤, 흡수량은 1,500만 톤/연으로, 2007년 대비 탄소저장량은 1% 감소, 흡수량은 1% 증가하였음 ○ 2019년 기준, 주요 탄소흡수·저장원인 산림의 탄소저장량은 7억 9,000만 톤, 흡수량은 1,500만 톤/연임. 2007년 대비 산림이 3% 감소하였으나, 탄소흡수·저장계수가 높은 활엽수림이 76% 증가하면서 산림의 탄소저장량은 2%, 흡수량은 1% 증가하였음 ○ 2019년 기준, 탄소저장 상위 지역은 경북(2억만 톤), 강원(1억 9,200만 톤), 전남(1억 600만 톤), 흡수 상위 지역은 강원(300만 톤/연), 경북(300만 톤/연), 경남(200만톤/연)임. 2007년 대비 서울, 경북, 강원, 울산을 제외한 모든 지역에서 탄소저장량이 1~14% 감소하였으며, 세종, 충남, 충북, 전북, 부산은 흡수량도 1~9% 감소하였음 3. 가치추정 □ 생태계 탄소흡수·저장 통합분석 툴킷은 2021년에 가치추정 단계의 단위가치 입력 프로세스를 개편함 ○ 국내뿐만 아니라 해외(EU-ETS)의 탄소배출권 가격을 단위가치 자료로 제공하며, 원하는 시점의 가격 자료를 선택할 수 있도록 함 ○ 시점으로 인해 발생할 수 있는 물가조정의 문제점을 보완하기 위해 시점별 물가를 조정하는 서비스를 제공 중임 4. 분석결과 및 시사점 □ 탄소흡수·저장 통합분석 툴킷은 생태계·행정구역별로 관련 정보를 제공할 수 있어 탄소중립 정책 의사결정을 위한 기초 도구로 활용할 수 있으리라 기대됨 ○ 탄소흡수·저장원을 식별하고, 공신력 있는 모델·자료에 기반하여 탄소흡수·저장 서비스에 대한 정량·공간 평가를 수행하였으며, 이의 경제적 가치를 산정하여 툴킷을 통해 관련 정보를 제공하였음 ○ 그러나 생태계 탄소흡수·저장량은 입력단위·자료에 크게 의존하므로, 툴킷의 실질적 활용을 위해 향후 탄소흡수·저장계수 설정방안, 표준·객관화된 입력자료 연계방안 등 탄소흡수·저장 평가·검증 고도화 연구가 필요함 Ⅱ. 물(담수) 공급 통합분석 사례연구 1. 개요 및 분석범위 설정 □ 건전한 물순환 달성을 위한 선제 작업으로, 생태계의 물 공급량과 가치에 대한 과학적·객관적 평가가 가능한 물 공급 통합분석 툴킷을 구축하였음 ○ 2017년 연구에서는 환경영향 정량화와 단위가치 연계를 위한 툴킷 기반을 구축하였고, 2021~2022년 연구에서는 툴킷을 개선·안정화시켜 구축 완료하는 것을 목표로 함 - 2021~2022년 연구에서는 2017년 연구에서 설정한 생태계 유형과 생태계서비스 평가 모델을 적용하되 입력자료·계수를 보완하여(2022년) 2019년 당시의 생태계물 공급 기능을 평가·검증하고(2022년), 경제적 가치산정 체계를 개편·적용하여 (2021~2022년) 지속가능한 물관리를 위한 정책 의사결정을 지원하고자 하였음 2. 영향평가 □ 2009년 기준, 불투수지역인 도시지역을 제외한 생태계의 물 공급량은 727억 톤임 ○ 물 공급을 담당하는 주요 생태계는 산림과 경작지로, 2009년 기준 산림은 472억톤(65%), 경작지는 209억 톤(29%)의 물을 공급하였음 ○ 2009년 기준, 물 공급 상위 유역은 한강 유역으로, 총 262억 톤(36%)의 물을 공급하였음. 낙동강, 영산ㆍ섬진강, 금강 유역은 195억 톤(27%), 145억 톤(20%), 117억톤(16%)의 물을 공급하였음 ○ 2009년 기준, 물 공급 상위 지역은 강원(148억 톤, 21%), 경북(105억 톤, 15%), 전남(93억 톤, 13%), 하위 지역은 서울(3억 톤), 세종(3억 톤), 대전(3억 톤)임 3. 가치추정 □ 생태계가 공급하는 물 공급량의 가치를 추정하기 위해서는 최종적으로 공급된 물이 어떻게 사용되었는지를 고려하여야 함 ○ 생태계에서 공급된 물의 일부는 인간이 생활하거나 농사를 짓거나 산업부문 생산에 활용되는 등 수자원으로 이용되고, 사용되지 않은 나머지 물은 추후의 사용을 위해 저장되거나 생태계에 잔존하며 생태기능을 유지하는 용도로 활용됨 ○ 생활용수나 공업용수에 사용되는 가격을 공급된 물 공급 총량에 곱하는 것은 생태계가 공급한 물 공급서비스에 대한 가치를 과대 혹은 과소 추정할 수 있음 □ 본 연구에서는 생태계 물 공급서비스 가치평가에 있어 물의 활용을 크게 생활용수, 공업용수, 농업용수로 구분하고, 공급량 중 용수로 이용되지 않은 나머지 수량(residual)은 저장되지 않고 생태계 유지를 위해 모두 사용된 것으로 가정하고자 함 ○ 총 공급 대비 용수로 이용된 이용비율은 약 50%(정확히는 0.4895를 적용)로 가정하고, 국가수자원관리종합정보시스템(이하 WAMIS)에서의 실제 과거의 용수별 사용비율을 적용하여 사용처별 추정량 도출 ○ 생활용수와 공업용수는 환경부 연도별 ‘상수도통계’ 중 생활용수와 공업용수의 단위당 수도요금을 단위가치로 사용 ○ 농업용수는 수도요금을 받지 않고 있어 사용목적인 농산물 생산 투입재로서의 부가가치를 통해 단위가치를 도출하는 ‘잔존가치접근법’ 활용 ○ 생태계 유지를 위해 활용되는 생태계 잔존량의 경우 사람들의 지불의사(WTP)를 추정하고, 이를 단위가치로 적용함으로써 해당 가치를 일부 반영 4. 분석결과 및 시사점 □ 물 공급 통합분석 툴킷은 생태계·유역·행정구역별로 관련 정보를 제공할 수 있어 물관리 정책 의사결정을 위한 기초 도구로 활용할 수 있으리라 기대됨 ○ 2022년에는 입력계수·자료를 보완하여 2019년 생태계 물 공급 기능을 평가·검증하고, 경제적 가치산정 체계를 적용하여, 지속가능한 물관리를 위한 정책 의사결정을 지원하고자 함 Ⅲ. 대기오염 건강영향 통합분석 사례연구 1. 개요 및 분석범위 설정 □ 대기오염 건강영향 통합분석 툴킷은 주요 대기오염물질(NOx, SO₂, PM_2.5, NH₃, VOC) 배출로 인한 초미세먼지(PM_2.5) 발생이 조기사망에 미치는 영향과 그 피해비용 평가를 지원함 ○ PM2.5을 유발하는 다양한 대기오염물질별 피해를 구분하여 평가할 수 있을 뿐만 아니라, 오염원 유형별(점오염원, 선오염원, 면오염원) 피해비용을 구분하여 평가할 수 있음 2. 영향평가 □ 건강영향 피해비용을 산정하기 위해서는 ① 오염물질별, 오염원별 배출량이 어떻게 되는지, ② 배출된 오염물질이 대기 중에 확산되어 대기오염 농도가 최종적으로 어떻게 변하는지, ③ 대기오염 농도에 노출된 인간이 얼마만큼의 건강피해를 입는지에 대한 물리적 환경영향 혹은 건강영향 정량화가 필요함 ○ 오염물질 배출량을 농도 변화로 전환하기 위해서 대기오염물질별, 오염원별 PM_2.5 전환율값 활용 ○ 대기오염 농도가 인간에 미치는 영향은 선행연구의 농도-반응계수 활용 3. 가치추정 □ 여러 가지 대기오염 건강영향 중 본 연구의 통합분석 툴킷은 ‘초미세먼지(PM_2.5) 장기 노출로 인한 조기사망 피해’를 일차적 평가대상으로 함 ○ 조기사망자 수로 나타난 영향평가 결과를 경제적 피해비용으로 환산하기 위해 사망위험감소가치(VSL: Value of Statistical Life) 적용 - 안소은 외(2019, p.8)에서 제시한 선행연구 사망위험감소가치(VSL) 자료 중 일부 선행연구의 사망위험감소가치 자료를 선택하여 사용 4. 분석결과 및 시사점 □ 대기오염 건강영향 통합분석 툴킷을 통해 PM_2.5 장기노출로 인한 조기사망의 오염물질별, 오염원별 단위 피해비용 결과를 확인할 수 있음 □ 향후 자료 및 방법론의 지속적인 업데이트를 통해 평가결과의 신뢰도 제고가 필요함 ○ 특정 지자체 혹은 특정 사업을 대상으로 한 세부적인 정책평가를 위해서는 더 세밀한 단위에서의 자료 적용이 요구됨 ○ 자료 개선의 노력과 동시에 미세먼지로 인한 피해범위를 입원, 외래와 같은 여타 건강영향으로 확대하고, 나아가 불편함(삶의 질)에 미치는 사회적 비용으로까지 확대하는 등 연구의 범위를 더욱 확장할 필요가 있음 Ⅳ. 화학물질 건강영향 통합분석 사례연구 1. 개요 및 분석범위 설정 □ 화학물질 건강영향 통합분석 툴킷의 개요 ○ 화학물질의 건강영향 평가 및 가치추정 연구는 환경경제 통합분석을 위한 환경가치 종합연구의 일환으로 추진되었으며, 2016~2020년에 걸쳐 수행되었음 - 2016~2018년: 화학물질 건강영향 평가를 위한 평가방법론 마련 및 수은 또는 납에 대해 방법론 시범 적용 - 2019~2020년: 화학물질 건강영향 대상 화학물질 확대를 위한 사례연구 수행 ○ 올해 연구에서는 화학물질 건강영향 평가방법론에 대한 기존 연구 결과를 종합하여 화학물질 건강영향 통합분석 툴킷을 마련함 - 화학물질은 물질별로 각각의 종결점이 있으며, 이 물질들이 가진 종결점을 화폐화하는 과정을 통해 가치추정 수행 - 대상 화학물질로 수은을 시범 선정하였으며, 향후 대상 화학물질을 확대할 수 있도록 모델 설계 2. 영향평가 □ 화학물질 및 종결점 설정 ○ 화학물질: 화학물질 건강평가방법론 구축을 위해 시범 적용된 ‘수은’으로 결정 ○ 종결점: 수은의 종결점은 IQ 저하, 경미한 지적 장애(MMR) 및 심혈관계 조기사망으로 결정 □ 화학물질 건강영향 ○ 수은-IQ 저하 - 국내 자료 가용 현황을 고려하여 ‘모발 중 수은 농도’를 선택하고 해당 농도와 IQ 변화 용량반응(DR)함수 적용 ○ 수은-MMR - 신생아의 수은 노출로 인한 경미한 지적 장애(MMR)는 WHO의 수은 피해비용 산정 시트를 활용하여 DALYs값 도출 ○ 수은-심혈관계 조기사망 - 메타분석을 통해 용량반응(DR)함수를 선정하고, 상대위험도(RR)를 적용하여 수은 노출로 인한 심혈관계 사망자 추정 ○ 통합분석 툴킷에서는 사용자가 제시된 함수식을 바탕으로 입력값을 변경할 수 있도록 옵션 제공 3. 가치추정 □ 수은-IQ 저하 ○ IQ 변화 단위가치 적용: 2차 연도에 수행된 IQ당 평균 피해비용 적용 ○ Mincer의 임금방정식 적용: 교육 수준 변화에 따른 소득 변화를 IQ 하락으로 인한 연간 소득 손실 총합으로 도출 □ 수은-MMR ○ DALYs의 단위가치에 사망위험감소가치(VSL)에 근거한 연간사망위험감소가치 (VOLY: Value of Life Year)값을 적용하여 도출 ○ 사망위험감소가치(VSL)는 안소은 외(2018a, pp.86-87)에서 메타분석을 통해 도출 □ 수은-심혈관계 조기사망 ○ 안소은 외(2018a, pp.86-87)에서 메타분석을 통해 도출된 2015년 기준 사망위험감소가치(VSL)를 2016년으로 환산하여 적용 □ 통합분석 툴킷 ○ 통합분석 툴킷에서는 기본값을 위와 같이 제시하며, 사용자가 입력값을 변경할 수 있도록 옵션 제공 4. 분석결과 및 시사점 □ 툴킷의 최종 결과물 ○ 수은으로 인한 IQ 저하 피해비용 ○ 수은으로 인한 태아의 경미한 지적 장애(MMR) 피해비용 ○ 수은으로 인한 심혈관계 조기사망 피해비용 □ 시사점 ○ 화학물질은 각각 인체에 영향을 주는 기전(Pathway)이 달라 다른 통합분석 툴킷들과 달리 일반화하기 어렵고, 하나의 화학물질에도 다수의 종결점이 존재할 수 있어 본 과제의 여타 툴킷들과는 차별적으로 구성됨 ○ 본 연구에서는 ‘수은’의 건강영향을 시범적으로 툴킷에 반영하였으며, 향후 대상 화학 물질을 확대하고자 함 ○ 2021년부터 국민환경보건기초조사 대상 화학물질이 대폭 확대되어 툴킷 적용대상 화학물질을 보다 구체적으로 검토할 수 있을 것으로 기대됨 ○ 향후 2022~2023년 연구에서는 화학물질 통합분석 시스템을 고도화하고, 화학물질 규제영향분석을 지원할 수 있는 방안을 모색하여 정책 활용도를 제고하고자 함 Ⅰ. Case Study with Integrated Analysis Toolkit for Carbon Absorption and Storage 1. Background and scope of analysis □ In preparation for a successful transition to a carbon-neutral society by 2050, this study develops the integrated analysis toolkit for carbon absorption and storage to evaluate the carbon absorption, storage, and value of the ecosystem services scientifically and objectively. ○ The 2016 study laid the foundation for toolkit development to link the quantitative environmental impact assessment and environmental unit values, and the 2021 study completed the development of the toolkit after much improvement and stabilization. - This year’s study aims to support the policy decision-making for achieving carbon neutrality by assessing and renewing the carbon absorption and storage capacity of ecosystems measured in 2019 to estimate its economic value using the ecosystem types and the carbon absorption and storage coefficients of the ecosystem established in the 2016 study. 2. Impact analysis □ As of 2019, the ecosystems stored 950 million tons of carbon and absorbed 15 million tons of carbon per year, with carbon storage reduced by 1% and carbon absorption increased by 1% compared with 2007. ○ As of 2019, forests, a major carbon sink, stored 790 million tons and absorbed 15 million tons of carbon per year. Although forests shrank by 3% compared with 2007, the carbon storage and absorption rose by 2% and 1%, respectively, following a 76% increase of the broad-leaf forest area with high carbon absorption and storage coefficient. ○ As of 2019, the regions with the largest carbon storage were Gyeongbuk (200 million tons), Gangwon (192 million tons), and Jeonnam (106 million tons), and the regions that absorb carbon the most were Gangwon (3 million tons/year), Gyeongbuk (3 million tons/year), and Gyeongnam (2 million tons/year). The carbon storage decreased by 1-14% in all regions except Seoul, Gyeongbuk, Gangwon, and Ulsan, and the carbon absorption also fell by 1-9% in Sejong, Chungnam, Chungbuk, Jeonbuk, and Busan compared to 2007. 3. Value estimation □ The unit value input process in the stage of environmental evaluation in the integrated analysis toolkit for carbon absorption and storage was revised in 2021. ○ The toolkit not only provides the price information of both domestic and overseas (EU-ETS) carbon credit as unit value data, but also allows users to select the price information at the desired time. ○ To complement the price difference at different points of time, the toolkit currently provides services to adjust inflation at different points of time. 4. Analysis results and implications □ The integrated analysis toolkit for carbon absorption and storage of ecosystems is expected to be used as a basic tool for the decision-making of carbon net-zero policy since it can provide relevant data for each ecosystem and administrative district. ○ The toolkit provided relevant information by identifying the source of carbon absorption and storage and conducting quantitative and spatial evaluation on the carbon absorption and storage services based on reliable models and data. ○ However, as the ecological carbon absorption and storage largely depends on the input unit and data, it requires further study on the assessment and verification of carbon absorption and storage, including research on methods to set coefficients for carbon absorption and storage and ways to incorporate standardized and objective input data. Ⅱ. Case Study with Integrated Analysis Toolkit for Water (Freshwater) Supply 1. Background and scope of analysis □ As a prior step to achieving the sound water cycle, an integrated analysis toolkit for water supply was developed which can evaluate the water supply volume and the value of the ecosystem services in a scientific and objective manner. ○ The 2017 study laid the foundation for toolkit development to link the quantitative environmental impact assessment and environmental unit values, and the 2021-2022 study aims to improve and stabilize the toolkit in an effort to complete the development of the toolkit. - The 2021-2022 study aimed to support the policy decision-making for sustainable water management (2021-2022) by applying the type of ecosystem and the ecosystem service evaluation model set in the 2017 study with revised input data and coefficients (2022) to assess and verify the water supply function of the 2019 ecosystem (2022) and revise and apply the economic evaluation system (2021-2022). 2. Impact analysis □ As of 2009, the water supply volume of the ecosystems except the impervious urban area was 72.7 billion tons. ○ Forests and arable land are key ecosystems that supply water, and as of 2019, the forests supplied 47.2 billion tons of water (65%) and the arable land supplied 20.9 billion tons of water (29%). ○ As of 2009, the Han River basin supplied the largest water volume of a total of 26.2 billion tons (36%). The Nakdong River, Yeongsan & Seomjin River, and Geum River basins supplied 19.5 billion tons (27%), 14.5 billion tons (20%), and 11.7 billion tons (16%) of water, respectively. ○ As of 2009, the region that supplied the largest amount of water was Gangwon (14.8 billion tons, 21%), followed by Gyeongbuk (0.5 billion tons, 15%) and Jeonnam (9.3 billion tons, 13%) and the regions that supplied water in relatively smaller volumes were Seoul (300 million tons), Sejong (300 million tons), and Daejeon (300 million tons). 3. Value estimation □ To estimate the value of the water supply volume of the ecosystems, it is necessary to take into account how the supplied water has been consumed at the final stage. ○ Part of water supplied by the ecosystems is used for living, farming or industrial productions, and the residual water is stored for future use or remains within the ecosystems to sustain the ecological functions. ○ Multiplying the price of residential or industrial water by the total water supply volume could either over- or underestimate the value of water supply service of the ecosystems. □ This study classifies the types of water consumption into residential, industrial, and agricultural water in the estimation of water supply service value of the ecosystems, and the residual water not used for the above purposes is assumed to be fully consumed for maintaining the ecosystems. ○ This study estimates the water consumption volume for each purpose by applying the past water use ratio in the Water Resources Management Information System (WAMIS), assuming that the ratio of water consumption to the total supply is approximately 50% (0.4895, to be exact). ○ This study uses the water rate per unit of the residential and industrial water in the annual “statistics of waterworks” by the Ministry of Environment as unit values for the residential and industrial water. ○ Since agricultural water does not charge a water rate, this study applies the “residual value approach” to derive unit values through added value as an input for agricultural production, the purpose of the water supply. ○ As for the residual water in the ecosystems used to maintain the ecosystem, this study reflects its value partially by estimating people's willingness to pay (WTP) and applying it as unit values. 4. Analysis results and implications □ The integrated analysis toolkit for water supply is expected to be used as a basic tool for the decision-making of water management policy since it can provide relevant data for each ecosystem, basin, and administrative district. ○ The toolkit aims to complement the input coefficient and data in 2020 to assess and verify the water supply function of the ecosystem measured in 2019 and support the policy decision-making for sustainable water management by applying the economic evaluation system. Ⅲ. Case Study with Integrated Analysis Toolkit for Health Impacts of Air Pollution 1. Background and scope of analysis □ The Integrated Analysis Toolkit for Health Impacts of Air Pollution supports the evaluation of the impact of PM_2.5 generated by key air pollutants (NOx, SO₂, PM_2.5, NH₃, and VOC) on premature death and the cost of damage. ○ The toolkit not only assesses the damage per each air pollutant that causes PM_2.5, but also evaluates the cost of damage for each source of pollution (point source, line source, and surface source). 2. Impact analysis □ To estimate the damage costs resulting from health impacts, quantitative analysis of physical environmental impact or health impact is required so as to identify ① the emissions of each source of pollution per pollutant, ② how how the diffusion of air pollutants in the atmosphere finally changes the level of air pollution, and ③ how much health damage is inflicted on the people exposed to air pollutant concentrations. ○ To convert the air pollutant emissions into concentration changes, this study uses the PM_2.5 conversion rate for each air pollutant and source of pollution. ○ This study uses the concentration-response coefficients from previous studies to estimate the impact of air pollutant concentrations on people. 3. Value estimation □ The Integrated Analysis Toolkit in this study sets “the premature death caused by long-term exposure to PM_2.5” as the primary evaluation target among numerous health impacts of air pollution. ○ To convert the impact analysis result indicated by the number of premature deaths into the economic cost of damage, the Value of Statistical Life (VSL) was applied. - The VSL data from Ahn et al. (2018) and OECD (2012) was used as final data. 4. Analysis results and implications □ Using the integrated analysis toolkit for health impacts of air pollution, the cost of damage of premature death caused by long-term exposure to PM_2.5 can be determined for each air pollutant and source of pollution. □ The reliability improvement of the analysis results is required through continuous updates of data and methodologies. ○ For more specific policy evaluation targeting a certain municipality or project, more detailed data is required. ○ Along with the effort to enhance the quality of data, the scope of research needs to be expanded further to include other health impacts such as hospitalization and outpatients due to particulate matter and even the social cost associated with discomfort (the quality of life). Ⅳ. Case Study with Integrated Analysis Toolkit for Health Impacts of Chemical Substances 1. Background and scope of analysis □ Background of Integrated Analysis Toolkit for Health Impacts of Chemical Substances ○ As part of the environmental valuation study for integrated environmentaleconomic analysis, the health impact analysis and value estimation of chemical substances were pursued and conducted from 2016 to 2020. - 2016-2018: A methodology for health impact analysis of chemicals was established and applied to mercury or lead as a trial run. - 2019-2020: Case studies were conducted to expand the target chemicals for health impact analysis. ○ In this year’s research, the Integrated Analysis Toolkit for Health Impacts of Chemical Substances is developed based on the comprehensive review of the previous studies on the health impact analysis methodologies of chemical substances. - Each chemical substance has its end-point and its value is estimated through the monetization of end-points. - Mercury has been selected as a target chemical in the trial run and the analysis model has been designed to expand the target chemicals in the future. 2. Impact analysis □ Chemical substances and end-points setting ○ Chemical Substances: Mercury that was used in the trial run for the development of health impact analysis methodologies of chemical substances was selected. ○ End-points: The decline in IQ, Mild Mental Retardation (MMR), and premature death due to cardiovascular diseases were determined as the end-points of mercury. □ Health impacts of chemical substances ○ Mercury-decline in IQ - Based on the data available in Korea, “mercury concentrations of hair” has been selected as the analysis subject and the dose-response (DR) function of the corresponding concentration and changes in IQ has been applied. ○ Mercury-MMR - DALYs values are estimated using the Mercury Sheet of WHO (2008) for the MMR due to mercury exposure of newborns. ○ Mercury-premature death due to cardiovascular diseases - DR function is selected by meta-analysis, and relative risk (RR) is applied to estimate the number of premature deaths caused by cardiovascular diseases due to mercury exposure. ○ The Integrated Analysis Toolkit offers options for users to change the input data based on the presented functions. 3. Value estimation □ Mercury-decline in IQ ○ Application of unit values of changes in IQ: the average cost of damage per IQ analyzed in the second year is applied. ○ Application of Mincer wage equation: income changes according to changes in education levels are calculated by adding annual income losses resulting from the decline in IQ. □ Mercury-MMR ○ The Value of Life Year (VOLY) based on VSL is applied to the unit value of DALYs. ○ VSL is determined through meta-analysis from Ahn et al. (2018). □ Mercury-premature death due to cardiovascular diseases ○ The VSL of 2015 presented in Ahn et al. (2018) by meta-analysis was converted to the 2016 value and applied. □ Integrated Analysis Toolkit ○ Integrated Analysis Toolkit offers default values as described above and provides options for users to change the input data. 4. Analysis results and implications □ Final product of the toolkit ○ Damage costs of decline in IQ caused by mercury exposure ○ Damage costs of MMR in newborns caused by mercury exposure ○ Damage costs of premature deaths due to cardiovascular diseases due caused by mercury exposure □ Implications ○ This toolkit is distinguished from other integrated analysis toolkits in that it is difficult to generalize this toolkit as health impacts of chemical substances have different pathways and multiple end-points can exist for a single chemical substance. ○ In this study, the toolkit was applied to mercury as a trial, butit(the toolkit) will be applicable to more chemicals in the future. ○ A more detailed review of chemicals for toolkit application will be possible since the subject chemical substances for the Korean National Environmental Health Survey will be expanded from 2021. ○ The future studies from 2022 to 2023 will seek ways to advance the integrated analysis system for chemical substances and support the impact analysis of chemical regulations in an effort to promote its utilization in policy-making.

목분-폴리프로필렌 복합재의 수분흡수율: 목재수종, 충진제 입자크기 및 상용화제의 영향

강인애 ( In Aeh Kang ),이선영 ( Sun Young Lee ),도금현 ( Geum Hyun Doh ),전상진 ( Sang Jin Chun ),윤승락 ( Seung Lak Yoon ) 한국목재공학회 2010 목재공학 Vol.38 No.4

The effects of wood species, chemical components, filler loading level, filler particle size, and coupling agent on the water absorption property of the wood flour filled polypropylene (PP) composites were investigated in this study. After 500, 1,000, 1,500, 2,000, 2,500 and 3,000 hr water immersion, Quercus (Quercus accutisima Carr.) and Maackia (Maackia amuresis Rupr. et Maxim) showed significantly lower water absorption properties compared to Larix (Larix kaempferi Lamb.). As wood flour loading increases from 10 to 50 wt%, most wood species showed increased water absorption after a given immersion period. Particle size of wood flour proved to have very significant effects on water absorption of the composites. The effect of coupling agent was positive in terms of lowering water absorption of the composites. As the treatment level of coupling agent increases, the water absorption of the composites decreases. The lowest water absorption was obtained at the lower wood flour loading (Maackia), smaller particle size and by the addition of coupling agent. Thickness swelling of the composites shows close dependency on water absorption.

Monitoring the water absorption in GFRE pipes via an electrical capacitance sensors

Altabey, Wael A.,Noori, Mohammad Techno-Press 2018 Advances in aircraft and spacecraft science Vol.5 No.4

One of the major problems in glass fiber reinforced epoxy (GFRE) composite pipes is the durability under water absorption. This condition is generally recognized to cause degradations in strength and mechanical properties. Therefore, there is a need for an intelligent system for detecting the absorption rate and computing the mass of water absorption (M%) as a function of absorption time (t). The present work represents a new non-destructive evaluation (NDE) technique for detecting the water absorption rate by evaluating the dielectric properties of glass fiber and epoxy resin composite pipes subjected to internal hydrostatic pressure at room temperature. The variation in the dielectric signatures is employed to design an electrical capacitance sensor (ECS) with high sensitivity to detect such defects. ECS consists of twelve electrodes mounted on the outer surface of the pipe. Radius-electrode ratio is defined as the ratio of inner and outer radius of pipe. A finite element (FE) simulation model is developed to measure the capacitance values and node potential distribution of ECS electrodes on the basis of water absorption rate in the pipe material as a function of absorption time. The arrangements for positioning12-electrode sensor parameters such as capacitance, capacitance change and change rate of capacitance are analyzed by ANSYS and MATLAB to plot the mass of water absorption curve against absorption time (t). An analytical model based on a Fickian diffusion model is conducted to predict the saturation level of water absorption ($M_S$) from the obtained mass of water absorption curve. The FE results are in excellent agreement with the analytical results and experimental results available in the literature, thus, validating the accuracy and reliability of the proposed expert system.

연구논문 : 공기 중 메틸에틸케톤 제어를 위한 Pilot-Scale 흡수 시스템의 운영인자 분석

조완근 ( Wan Kuen Jo ),김왕태 ( Wang Tae Kim ) 한국환경과학회 2011 한국환경과학회지 Vol.20 No.4

Unlike many laboratory-scale studies on absorption of organic compounds (VOCs), limited pilot-scale studies have been reported. Accordingly, the present study was carried out to examine operation parameters for the effective control of a hydrophilic VOC (methyl ethyl ketone, MEK) by applying a circular pilot-scale packed-absorption system (inside diameter 37 cm × height 167 cm). The absorption efficiencies of MEK were investigated for three major operation parameters: input concentration, water flow rate, and ratio of gas flow-rate to washing water amount (water-to-gas ratio). The experimental set-up comprised of the flow control system, generation system, recirculation system, packed-absorption system, and outlet system. For three MEK input concentrations (300, 350, and 750 ppm), absorption efficiencies approached near 95% and then, decreased gradually as the operation time increased, thereby suggesting a non-steady state condition. Under these conditions, higher absorption efficiencies were shown for lower input concentration conditions, which were consistent with those of laboratory-scale studies. However, a steady state condition occurred for two input concentration conditions (100 and 200ppm), and the difference in absorption efficiencies between these two conditions were insignificant. As supported by an established gas-liquid absorption theory, a higher water flow rate exhibited a greater absorption efficiency. Moreover, as same with the laboratory-scale studies, the absorption efficiencies increased as water-to-gas ratios increased. Meanwhile, regardless of water flow rates or water-to-gas ratios, as the operation time of the absorption became longer, the pH of water increased, but the elevation extent was not substantial (maximum pH difference, 1.1).

Study on Reliability of Water Absorption Diagnosis through Precise Water Absorption Test

Hee-Soo Kim,Yong-Chae Bae,Hee-Dong Kim 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.5

Accidents caused by water absorption in water-cooled generator stator windings often occur all over the world. The absorption into the insulator of the coolant, which is used to cool down the heat generated by stator windings during operation, leads to the deterioration of dielectric strength, and insulation breakdown. An insulation breakdown may cause not only an enormous economic loss but also a very serious grid accident that would compromise stable supply of electric power. More than 50 % of domestic generators have been in operation for more than 15 years, and water absorption tests performed on 50 water-cooled generator stator windings during a five-year planned preventive maintenance period beginning in 2006 identified water absorption problems in 10 of them, all of which required repair. Because the existing water absorption test detects this problem by utilizing stochastic methods after measuring the capacitances at the final positions of insulation breakdown, its accuracy is limited. This study demonstrates that water absorption can be more accurately diagnosed by utilizing method along with a more precise one.

충남 서산에서 가을철에 관측한 초미세먼지의 광흡수 특성

박승식(Seungshik Park),이광열(Kwangyul Lee),이민도(Mindo Lee) 한국대기환경학회 2020 한국대기환경학회지 Vol.36 No.3

In this study, a real-time monitoring of aerosol light absorption was conducted using a dual-spot seven-wavelength aethalometer with a PM<SUB>2.5</SUB> impactor between October 18 and November 05, 2019 at Chungcheong region air quality research center in Seosan, Chungcheongnam-do. Over the study period, light absorption coefficients of atmospheric aerosol and brown carbon (BrC) at wavelength of 370 nm peaked in both the morning (07:00~09:00 LT) and evening hours (17:00~24:00 LT), but with more predominance of their absorption coefficients during nighttime hours. This could possibly be due to light-absorbing organic aerosols from biomass burning emissions at night around the sampling site. Contribution of black carbon (BC) and BrC absorption to total aerosol light absorption at 370 nm wavelength was 70.4 and 29.6% at 08:00 LT and 53.5 and 46.4% at 18:00 LT, respectively. For the time when the contribution of BC absorption (~33%) to total aerosol absorption at 370 nm was approximately two-fold lower than BrC absorption contribution (~67%), absorption Ångström exponent (AAE) values of aerosol particles in the 370~520 nm wavelength range (AAE<SUB>370-520</SUB>) were greater than 2.0, reaching maximum of 3.1. On the other hand, when BC absorption accounted for most of the total aerosol absorption, aerosol AAE<SUB>370-520</SUB> values were close to 1.0. For the periods when light absorption by aerosol particles significantly increased, AAE<SUB>370-660</SUB> of BrC estimated between the wavelengths of 370 and 660 nm was in the range of 3.4~5.1. The difference in AAE values among the excursion periods was likely due to the considerable difference in water-soluble and insoluble BrC absorption. Furthermore, correlation analyses among water-soluble organic carbon (OC), total OC concentrations, and BrC absorption coefficients at 370 nm wavelength suggest that light absorption by BrC particles was clearly influenced by not only water-soluble OC fractions, but water-insoluble OC fractions.

송이 균환내 토양수분의 시공간적 변화

구창덕 ( Gu Chang Deog ),김재수 ( Kim Jae Su ),이상희 ( Lee Sang Hui ),박재인 ( Park Jae In ),안광태 ( An Gwang Tae ) 한국산림과학회 2003 한국산림과학회지 Vol.92 No.6

Water is critically important for Tricholoma matsutake(Tm) growth because it is the major component of the mushroom by over 90%. The mushroom absorbs water through the below ground hyphal colony. Therefore, the objectives of our study were to investigate spatio-temporal water changes in Tm colonies. This study was carried out at Tm fruiting sites in Sogni Mt National Park, where the below-ground fairy-ring colonies have been irrigated. To identify spatial water status within the Tm soil colony soil moisture and ergosterol content were measured at six positions including a mushroom fruiting position on the line of the colony radius. To investigate temporal soil moisture changes in the soil colony, Time Domain Reflectometry(TDR) sensors were established at the non-colony and colony front edge, and water data were recorded with CRlOX data logger from late August to late October. Before irrigation, whereas it was 12.8% at non-colony, the soil water content within Tm colony was 8.0% at 0-5cm from the colony front edge, 6.2% at 10-15cm and 6.5-7.5% at 20-40cm. And the content was 12.1% at 80cm distance from the colony edge, which is similar to that at the non-colony. In contrast, ergosterol content which is proportional to the live hyphal biomass was only 0.4pg/g fresh soil at the uncolonized soil, while 4.9 ㎍/g fresh soil at the front edge where the hyphae actively grow, and 3.8 .㎍/g fresh soil at the fruiting position, l.l ㎍/g at 20cm distance and 0.4㎍/g in the 40cm rear area. Generally, in the Tm fungal colony the water content changes were reversed to the ergosterol content changes. While the site was watered during August to October, the soil water contents were 13.5-23.0% within the fungal colony, whereas it was 14.5-26.0% at the non-colony. That is, soil water content in the colony was lower by 1.0-3.0% than that in the non-colonized soil. Our results show that Tm colony consumes more soil water than other parts. Especially the front 30cm within the hyphal colony parts is more critical for soil water absorption.

발전기 고정자 권선의 흡습 진단

배용채(Y. C. Bae),김희수(H. S. Kim),이두영(D. Y. Lee) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월

Water leak for the water-cooled generator stator windings affects seriously the availability and the reliability of power plants. Generally, water absorption test is conducted in the power plant during outage in order to confirm if leak part is in the bars or not. In this paper, it is described that the capacitance of winding bars is measured by using the developed water absorption instrument system and the water absorption of winding bars is evaluated by using the stochastic methods. The good results by proposed diagnosis technique can be got. It is expected that the reliability of diagnosis for water absorption is increased if the proposed methods are applied to evaluate the water absorption of stator winding bars.

흙 입자의 흡수율을 고려한 체적함수비와 중량함수비의 관계에 관한 실험적 고찰

이형규(Lee Hyoungkyu),이인(Lee In) 한국지반환경공학회 2011 한국지반환경공학회논문집 Vol.12 No.3

실무에서 불포화토의 적용이 증가하고 있다. 불포화토의 가장 큰 특징은 체적함수비와 모관흡수력의 관계를 나타내는 함수특성곡선이다. 일반적으로 체적함수비는 측정의 어려움으로 인하여 중량함수비를 측정한 후 관계식을 통하여 체적함수비를 구한다. 이 경우 흙의 간극과 비중을 이용하여 관계식이 성립되는데 사실 물은 흙 입자 자체에도 포함되어 있다. 그러므로 실제 체적함수비는 중량함수비를 관계식으로 변화한 값과 다르게 된다. 본 연구에서는 실험을 통하여 얻어진 흙 입자의 흡수율을 고려하여 체적함수비와 중량함수비의 관계를 제시하는 데 있다. Recently, the application of unsaturated-soil theory is concerned in practice. Most characteristics of unsaturated-soil is the relationship between volumetric water contents and matric suction. Usually the volume water contents is estimated by the relationship between gravity water contents and volume water contents because of the difficulty of measurement of volumetric water contents. In this case, the water exists in only void of soil, and the relationship between gravity water contents and volume water contents is calculated by only water in void, but in fact, the water exists in the particle of the soil. So the real volume water contents is different with calculated volume water contents derived by the relationship containing only void water. The object of this research is to revise the relationship between volume water contents and gravity water contents by using the absorptivity tests of the soil particle.