THE ACID DEPOSITION MONITORING NETWORKIN EAST ASIA

20th

1

What is the reason for the establishmentof the EANET? What kind of activities
has the EANET been implementing?

In response to the concern of acid deposition issue in the region, the Acid
Deposition Monitoring Network in East Asia (EANET) was established in
2001, and in the 20 years of its existence, the EANET has implemented
various activities such as monitoring and reporting, data acquisition, capacity
building, research, and public awareness.

⁃⁃ Acid deposition has become a serious issue

with the increase of sulfur dioxide (SO2)emissions in many East Asian countries
s i n ce t h e 1 9 8 0 s , ow i n g t o t h e ra p i ddevelopment of secondary industries. Aciddeposition became a more serious problem
in the 1990s with the rise in nitrogen oxides( NOx ) , p r i m a r i l y o w i n g t o r a p i dd e ve l o p m e n t i n t h e a u t o m o b i l e a n dtransportation sectors.
Figure 1. The Second Session of Intergovernmental
Meeting of the EANET (Niigata, 2000)⁃⁃ In 1992, the adopted “Agenda 21” stated that the experience of the Convention on

Long-range Transboundary Air Pollution (CLRTAP) needed to be shared with otherregions of the world. During the firsthalf of the 1990s, countries in the East
Asian region expressed the need towork together on atmosphericenvironment issues, such as aciddeposition. The EANET started its
p r e p a ra t o r y p h a s e i n 1 9 9 8 , a n dsubsequently its regular phase in
2001. Since then the EANET has been
implementing the following activities:

Figure 2. The Twelfth Session of Intergovernmental Meetingof the EANET (Niigata, 2010)

1

-

‌
Monitoring
wet deposition, dry deposition, soil/vegetation, inland aquatic
environment and catchment;-‌Collection,
evaluation, analysis and provision of monitoring data of aciddeposition in the Participating Countries;-‌
Capacitybuilding on monitoring and research activities in acid deposition andrelated air pollution issues in the Participating Countries;-‌
Research
activities on acid deposition and related air pollution problems and theirimpact on ecosystems; and-‌Public awareness activities on acid deposition and related air pollution issues.

2

How has the EANET helped solve aciddeposition and related air pollution
problems in the East Asian region?

To solve acid deposition and related air pollution problems, it is essential tounderstand the current status and trends of acid deposition and related air
pollution in the region by referring to monitoring data. The EANET provides
comprehensive monitoring data in the East Asian region, and has been
continuously developing its monitoring network over the last 20 years. To
support policymakers, the EANET periodically produces regional assessment
reports based on monitoring results from its activities.

⁃⁃ It is essential to understand the current status and trends of acid deposition andrelated air pollution to solve the problems in East Asia, by referring to themonitoring data. The EANET, therefore, has been developing monitoring activities inthe East Asian region towards high-quality data. Furthermore, the EANET has been
continuously developing its monitoring network over the last 20 years.

⁃⁃ Reliability and traceability of monitoring data are important characteristics of themonitoring network. EANET has also prioritized maintaining the quality of themonitoring data by conducting quality assurance/quality control (QA/QC) activities
such as the development of standard operational procedures (SOPs) and
implementation of inter-laboratory comparison projects. Capacity building activities,
such as the fellowship program and individual training at the Network Center for
EANET and the technical missions dispatched to the Participating Countries, havebeen conducted to further enhance relevant capabilities.

⁃⁃ EANET monitoring data are accessible to the public via the EANET Data Report/

Monitoring System (https://monitoring.eanet.asia/document/public/index) for bothresearch activities and air quality management according to the related rules andregulations of data management.

2⁃⁃ EANET periodically publishes scientific regional assessment reports, Periodic Reporton the State of Acid Deposition in East Asia (PRSAD), based on the results of its
monitoring activities. The principal objective of the PRSAD is understanding andsharing the status and impacts of acid deposition in East Asia. EANET also publishes
the Report for Policy Makers (RPM) periodically to provide science-based
recommendations for decision-making processes.

Irkutsk
Mondy

Listvyanka

Ulaanbaatar

TereljRishiri
OchiishiPrimorskaya
Shizhan/Xi’an
Jiwozi/Xi’an

Sado-Seki
Niigata-maki
Kanghwa
Oki
Imsil
Happo

Jinyunshan/Chongqing

Tokyo
Ijira

Cheju

Haifu/Chongqing

Tsushima
Yusuhara
Xiaoping/Xiamen
Hedo
Hongwen/Xiamen
Hoa Binh Yen Bai
Ogasawara
Hanoi
Xiangzhou/Zhuhai
Vientiane
Cuc
PhuongZhuxiandong/Zhuhai
Mae Hia
Wuzhishan
YangonMt. Sto Tomas
Da Nang
Khanchanaburi
Metro Manilla
Sakaerat
Pathumthani
Los Banos
Phnom Penh
Bangkok
Ho Chi Minh
Samutprakarn Can Tho
Lijiang

Tanah Rata
Petaling Jaya

Kuching

Danum Valley
Daily

Kototabang

Urban

Maros
Serpong
Jembrana
JakartaBandung
LombokNumbers of wet deposition monitroing sites

Rural
Remote60

Numbers of dry deposition monitoring sites
PM2.5

50

60

PM10

40

40

O3

30

20

HNO3/
NH3
SO2

20
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019

0

CambodiaJapan
Mongolia
Republic of Korea
Viet Nam

China
Lao PDR
MyanmarRussiaIndonesia
Malaysia
Philippines
Thailand

10
0

2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019

80

WeeklyFigure 3. Location of wet deposition monitoring sites in 2019 (upper), Numbers of the wet deposition monitoring sites(lower left) and Numbers of dry monitoring sites (lower right) in 2000-2019 (Source: EANET  Data Reports 2000-2019)3

3

What is the current status of aciddeposition in East Asia?

Northeast Asia has seen a decrease in the annual amount of acid deposition,
especially that of sulfuric acid deposition, over the last twenty years. At the
global level, the amount of acid deposition in the East Asian region iscomparatively higher than that reported by the European Monitoring and
Evaluation Programme (EMEP) and the National Atmospheric Deposition
Program (NADP) in North America. This may be partly a result of volcanic
activity and naturally larger precipitation in East Asia.

⁃⁃ In the Northeast Asian region, the amount of wet deposition of non-sea-salt sulfateion (nss-SO42-) and hydrogen ion (H+) – the representative/typical indicators of aciddeposition – has decreased remarkably, not only in urban but also in rural andremote sites.

⁃⁃ In the Southeast Asian region, large wet deposition of these two ions along with thenitrate ion (NO3-) are prominent at some urban sites, showing regional diversity.

Wet depositon(meq m-2 y-1)
400
300

Distribution in 2015(10 - 90 %)Southeast Asia

Northeast Asia

nss-SO42-

A: 2000-2005, B: 2007-2012, C: 2014-2019
Urban

Rural

Remote

200
n=197
n=83

100
0
200
150

NO3-

100
n=84
n=197

50
0
200
150

H+

100
n=197
n=80

50
0

A B C

A B C

A B C

A B C

A B C

RussiaMongolia

China

R. of Korea

Japan

A B C

A B C

Philippines Viet Nam

A B C

A B C

A B C

A B C

A B C

A B C

Lao PDR Cambodia Thailand Myanmar Malaysia Indonesia

EMEP
NADP

Figure 4. Trends of wet deposition in EANET monitoring sites(Source: EANET Data Reports 2000-2019, EMEP, NADP)

4

⁃⁃ The amount of wet deposition indicated is currently higher than that reported by the

EMEP (for Europe) and the NADP (for North America), which do not target urban air
pollution. Therefore, the higher amount of acid deposition in the EANET region may
be due to the monitoring of urban sites. Additionally, volcanic activity in Northeast
Asia and large precipitation amounts in Japan and Southeast Asia may partiallycontribute to the large acid deposition in this region.

4

How important is acid deposition as
an environmental problem at present?

Acid deposition is not only a problem of acidification, but also that of various
related pollutants, including nitrogen compounds, which are deposited withthe acidic substances. Excessive nitrogen deposition can further influence
the health and resilience of ecosystems.
Surface ozone (O3) and particulate matter (PM), generated in connection
with the acidic pollutants, can also cause adverse effects on ecosystems
including crops. It is thus important to monitor and control the various aciddeposition and related air pollutants. The efforts of the Participating
Countries have helped tackle the acid deposition problem in the region.
These experiences and best practices accumulated over the past 20 years cancontribute to the control and management of other related air pollutants.

⁃⁃ The long-term deposition of acidic substances and excessive nitrogen compounds(nitric acid and ammonia) chronically disturb the nutrient cycle of terrestrial
ecosystems, including forests. The resulting decline of tree health and biodiversity
may further reduce the resilience of the affected ecosystem, resulting in its weakened
carbon-sink, disaster prevention, and water storage functions. Direct exposure to air
pollutants, such as O3 and PM, could adversely affect trees and crops too.

⁃⁃ The EANET Participating Countries have also made great efforts to understand theimpact of acid deposition and the importance of solving this problem over the past
20 years. The experiences and best practices accumulated can be used as references
to control and manage other related air pollutants.

5

5

How to understand the importance of cobenefits towards a cleaner environmentand sustainable development?

Evidence suggests that climate change and atmospheric issues are likely tobe solved simultaneously if coordinated measures and actions fromgovernments, enterprises, and the public are undertaken with considerationof co-benefits during the design and implementation of related strategies.

⁃⁃ Policies and actions considering climate as their primary objective could lead tomore impactful results in solving atmospheric issues if co-benefits’ coordination isbetter organized.

⁃⁃ The Third and Fourth Assessment Reports of the Intergovernmental Panel on

Climate Change (IPCC) distinguish between co-benefits (benefits that are intended
by the policy maker) and ancillary benefits (unintended benefits). Under thisdefinition, co-benefits in the climate and air areas are the benefits from policy
options intentionally implemented for both climate and atmospheric purposes
simultaneously.

⁃⁃ The co-benefits’ key sectors include but are not limited to energy supply,transportation, buildings, industry and human settlements and infrastructure. Table
5.1 provides an aggregated but qualitative overview of the potential co-benefits on
air pollution that could be realized if certain types of mitigation measures areenacted in different sectors such as energy supply-side transformations;
technological and behavioral changes in the transport, buildings, and industrial enduse sectors, and others. Promotion of the development of renewable energy and newenergy automobiles could contribute to achieving carbon reduction and cleaner air.
Reduction of fuel carbon intensity and energy intensity in the transportation sector
could reduce urban air pollution. In buildings sector, retrofits can achieve heating
and cooling energy savings and could also contribute to the co-benefits. A
sustainable lifestyle should be encouraged so as to establish a solid base for climate
adaption and a cleaner atmospheric hemisphere with improved consumption
patterns of the present and future generations in the region.

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Table 5.1. Potential co-benefits and adverse side-effects that could be realized if
certain types of mitigation measures are enacted in different sectors
Sectoral Mitigation Measures

Effect on Environment

Energy Supply
Nuclear replacing coal power

Ecosystem impact via↓ Air pollution (m/h) and coal mining (l/h)

Renewable energy (wind, photovoltaic (PV),concentrated solar power (CSP), hydro,
geothermal, bioenergy) replacing coal

Ecosystem impact via↓ Air pollution (except bioenergy) (m/h)

Transport
R e d u c t i o n o f f u e l c a r b o n i n t e n s i t y :⁃ Ec o s y s t e m i m p a c t o f e l e c t r i c i t y a n delectricity, hydrogen (H 2 ), compressed hydrogen via
natural gas (CNG), biofuels↓ Urban air pollution (m/m)
Reduction of energy intensity↓ Ecosystem and biodiversity impact via
reduced urban air pollution (m/h)

Compact urban form and improved transport
infrastructure Modal shift

Ecosystem impact via reduced↓ Urban air pollution (r/h)

Journey distance reduction and avoidance

Ecosystem impact via↓ Urban air pollution (r/h)

Buildings
Fuel switching, incorporation of renewableenergy, green roofs, and other measures
reducing GHG emissions intensity

Health impact in residential buildings via↓ Outdoor air pollution (r/h),↓ Indoor air pollution (r/h)

Retrofits of existing buildings (e.g., cool
roof, passive solar, etc.) Exemplary newbuildings efficient equipment

Health impact via↓ Outdoor air pollution (r/h),↓ Indoor air pollution (r/h)

Industry
Material efficiency of goods, recycling↓ Ecosystem impact via reduced local air
and water pollution and waste material
disposal (m/m)

Human Settlements and infrastructure
Increased accessibility↑ Air quality and reduced ecosystem andhealth impacts (m/h)

Mixed land use↑ Air quality and reduced ecosystem andhealth impacts (m/h)(Source: IPCC main report, AR5 Mitigation, P469-471)*Green arrows pointing up/down denote a positive/negative effect on the respective objective or concern.
Abbreviations for evidence: l = limited, m = medium, r = robust; for agreement: l = low, m = medium, h = high.

7

6What are the most important issues related
to air pollution, and why air pollution
matters need to be assessed in East Asia?

Impacts of air pollution on public health and ecosystems remain a significant
concern in East Asia. Research has been conducted on human health andpossible impacts of particulate matter (PM) and surface ozone (O3) on tree
species and agricultural crops in East Asia.
Recent studies suggest the complexity of air pollutants atmosphericbehaviors and their effects. There is a need to assess the effectiveness ofvarious measures contributing to reduction of acid deposition and related air
pollution considering the adverse effects caused by multiple air pollutants,
which could lead to applicable measures to further improve the air quality.

⁃⁃ Air pollution is a significant concern in the East Asian region. The main substances

affecting public health are nitrogen oxides (NOx), sulfur dioxide (SO2), O3, and PM.
According to the World Health Organization (WHO) Global Air Quality Guidelines(WHO, 2021), bronchitis in children is associated with long-term exposure to
Nitrogen Dioxide (NO2), while SO2 can affect the respiratory system and causes eye
irritation. Excessive O3 exposure can cause breathing problems, aggravate asthma,
and reduce lung functions. In recent years, fine particles (PM 2.5) have been asignificant concern, as they penetrate deep into the lungs, affecting both therespiratory and vascular systems.

⁃⁃ Some air pollutants also have adverse effects on the ecosystems. Possible impacts ofPM and O3 pose a potential threat for tree growth and agricultural production,
regardless of differences in estimated losses among the various studies undertaken.
PM and O 3 could therefore adversely affect food supply, forest resilience, andbiodiversity. Considering these impacts, the reduction of acid deposition and related
air pollution is of utmost importance to improve air quality.

8⁃⁃ The Sixth Assessment Report of the IPCC pointed out the complex atmosphericbehaviors of air pollutants and their effects; further, reducing emissions of SO2, theprecursor of sulfate aerosol, would increase the amount of sunlight reaching the
ground and thus affect the climate. It is therefore important that the Participating
Countries cooperate to deal with adverse effects caused by acid deposition andrelated air pollutants.

⁃⁃ During the past 20 years, the EANET Participating Countries have made great efforts

to reduce emissions of acidifying substances and related pollutants through methods
such as effective policies and advanced technologies and best practices from theirformer experiences. Therefore, there is a need to assess the various measures andtheir effectiveness in reducing acid deposition and related air pollution, which could
lead to applicable measures to further improve air quality.

7

How will the EANET activities
change in the future?

The EANET could expand its scope from its current activities of focusing on
monitoring acid deposition to atmospheric environmental substances andrelated activities, subject to the approval of all the Participating Countries.
The EANET could continuously enhance and strengthen cooperation andcollaboration among the Participating Countries by introducing new joint
projects.
Simultaneously, the EANET could strengthen its cooperation with relevantinternational organizations, research institutes, and countries, including thediversification of its funding mechanisms. Subsequently, the EANET could
flexibly deal with atmospheric environmental problems and promote a
synergy in the East Asian region.

9⁃⁃ The EANET has been monitoring acid deposition in East Asia since 2001. However,as described previously, owing to recent air pollution issues caused by PM2.5 and O3,
their impacts on human health and ecosystems are of significant concern in the East
Asian region. Therefore, the EANET aims to expand its scope from focusing on
monitoring of acid deposition to that of atmospheric environmental - related
substances and related activities. The Decision of the Twenty-second Session of theIntergovernmental Meeting on the EANET (IG22) stated that some activities relating
to air pollution are of major interest to the EANET Participating Countries but may
be beyond its current scope. Therefore, it was decided to start to expand the scope of
the Instrument for Strengthening the Acid Deposition Monitoring Network in East
Asia.

⁃⁃ The EANET will continuously enhance and strengthen cooperation and collaboration

by introducing new joint projects among the Participating Countries such as thepolicy dialogues and capacity building activities on PM2.5 and/or O3 and impact study
on agricultural crops, forest ecosystems, and inland water systems to improve theatmospheric environment in the East Asian region.

⁃⁃ Concurrently, the EANET will strengthen cooperation with relevant internationalorganizations and initiatives/programs , and the diversification of its funding
mechanisms subject to the approval of all the Participating Countries, to deal withatmospheric environmental-related issues and promote a synergy in the East Asian
region. The relevant international organizations initiatives/programs to cooperate
may include the Asia Pacific Clean Air Partnership (APCAP), the Integrated
Programme for Better Air Quality in Asia (IBAQ), the North-East Asia Clean Air
Partnership (NEACAP), the European Monitoring and Evaluation Programme(EMEP) and Working Group on Effects (WGE) under the Convention on Long-range
Transboundary Air Pollution (CLRTAP), Climate and Clean Air Coalition (CCAC),World Meteorological Organization (WMO), World Health Organization (WHO) etc.

10

EANET
ACID DEPOSITION MONITORINGNETWORK IN EAST ASIA
www.eanet.asia

Secretariat

Network Center

United Nations Environment
Programme Asia and the Pacific
2nd Floor, United Nations Building
Rajdamnern Avenue, Bangkok 10200,
ThailandTel: +662 288 1627
Fax: +662 288 2829
Email: eanetsecretariat@un.org
www.unenvironment.org

Asia Center for Air Pollution
Research (ACAP)
1182 Sowa, Nishi-ku,
Niigata-shi, 950-2144,
Japan
Te l : +81-25-263-0550
Fax: +81-25-263-0566
Email: eanet@acap.asia
www.acap.asia/en/