Data Report 2009

The Acid Deposition Monitoring Network in East Asia (EANET) was established to facilitate regional cooperation in monitoring acid deposition and its environmental and health effects across East Asia. The network's primary aim is to provide reliable and consistent data to inform policymakers on the severity of acid deposition and its ecological impacts, ultimately helping guide environmental regulations and strategies for mitigation.

The 2009 Data Report documents the monitoring activities across 13 countries—China, Indonesia, Japan, Mongolia, Philippines, Cambodia, Laos, Myanmar, Malaysia, Republic of Korea, Thailand, Vietnam, and Russia—throughout 2009. The monitoring activities covered wet deposition, dry deposition (air concentration), soil and vegetation health, and inland aquatic environments.

EANET has been operational since 2001, with the Network Center (NC) overseeing the compilation and quality assurance of the data submitted annually by the participating countries.

EANET Monitoring Network and Site Classification
EANET monitoring is conducted at 54 monitoring sites distributed across various ecological zones, which are categorized into urban, rural, and remote sites. These sites are grouped into two primary classifications:

Acid Deposition Monitoring Sites: These sites collect data on atmospheric deposition of acidic pollutants. They include three sub-categories:

Urban Sites: Located in industrialized or heavily urbanized regions, these sites measure the effects of acid deposition on human health, buildings, and infrastructure.

Rural Sites: Situated in less urbanized areas, these sites are used to assess the impact of acid deposition on agricultural land, forests, and natural ecosystems.

Remote Sites: Found in more isolated locations, these sites focus on measuring long-range transport and deposition of pollutants from distant sources.

Ecological Survey Sites: These sites monitor the impact of acid deposition on ecosystems, with two sub-categories:

Basic Survey Sites: Focus on collecting baseline data on the status of soils, vegetation, and aquatic ecosystems.

Ecosystem Analysis Sites: Used to assess the broader impacts of acid deposition on entire ecosystems through detailed terrestrial ecosystem and catchment analyses.

In 2009, monitoring was conducted at 20 remote, 13 rural, and 21 urban sites, spread across 13 countries.

Monitoring Methodologies

Wet Deposition Monitoring
Wet deposition refers to the acidic substances, primarily sulfates (SO4²⁻) and nitrates (NO3⁻), that are deposited to the Earth's surface through precipitation. Monitoring wet deposition involves several key steps:

Field Operations: The primary tool for collecting precipitation is the wet-only sampler, which collects rainwater only when rainfall is detected. For areas lacking automatic systems, manual samplers are employed.

Laboratory Operations: Precipitation samples are analyzed for various ions using standard methods:

Ion Chromatography (IC): Used to measure anions such as SO4²⁻, NO3⁻, Cl⁻, and cations like Na⁺, K⁺, Ca²⁺, Mg²⁺.

Atomic Absorption Spectroscopy (AAS): Primarily used to measure metals like Na⁺, K⁺, Ca²⁺, and Mg²⁺.

Spectrophotometry: Employed for measuring NH4⁺.

The ion concentrations are used to calculate the volume-weighted mean concentration of pollutants, which is then used to calculate the wet deposition amount in mmol/m².

Data Management and Quality Assurance: Data submitted by monitoring sites are reviewed for quality. Key metrics include:

Ion Balance (R1): Ensures that the sum of cations and anions is in reasonable agreement. This test is essential for data integrity.

Conductivity Agreement (R2): Verifies that the conductivity measured in the samples aligns with calculated values.

The data completeness is also assessed using Percent Precipitation Coverage Length (PCL) and Percent Total Precipitation (TP), ensuring that the samples are representative of the full precipitation event.

Dry Deposition (Air Concentration) Monitoring
Dry deposition refers to the atmospheric pollutants that settle on surfaces through gravitational and diffusive processes. This is primarily measured through:

Automatic Gas Monitors: These devices measure the concentrations of key gases, including SO2, NOx, and O3.

Filter Pack Method: Used to collect particulate matter (PM10) which is analyzed to determine the particulate concentration.

The dry deposition data helps estimate the total deposition flux of pollutants to the Earth's surface, which is crucial for assessing air quality and its health impacts.

Soil and Vegetation Monitoring
Soil and vegetation monitoring aims to assess the impact of acid deposition on terrestrial ecosystems:

Soil Sampling: Soil samples are collected to monitor changes in soil pH, nutrient content, and the presence of toxic metals resulting from acid deposition.

Vegetation Sampling: Plants are collected to analyze the damage caused by acidic precipitation, focusing on sensitive species that may exhibit clear signs of acidification stress, such as leaf damage and stunted growth.

3.4 Inland Aquatic Environment Monitoring
Acid deposition affects inland water systems, including lakes, rivers, and reservoirs. Monitoring in aquatic environments focuses on:

Water Sampling: Regular collection of water samples from selected freshwater bodies to assess the impact of acidification.

Chemical Analysis: Measuring SO4²⁻, NO3⁻, H⁺, and other pollutants in water samples, to determine changes in water chemistry and assess the broader effects on aquatic life.

Monitoring Results for 2009
Wet Deposition
The 2009 results revealed significant variation in wet deposition across the region, with Phnom Penh (Cambodia) and Haifu (China) showing the highest concentrations of pollutants. Seasonal variation was apparent, with elevated concentrations during the winter months when industrial activity is higher, leading to increased atmospheric emissions.

Volume-weighted average concentrations were calculated for each site, and the wet deposition amounts were reported for each month and annually.

Phnom Penh (Cambodia) recorded a total annual wet deposition amount of 15.4 mmol/m², with SO4²⁻ being the dominant ion, followed by NO3⁻.

Dry Deposition
Dry deposition was measured across several sites, including urban sites like Jakarta (Indonesia) and Tokyo (Japan), where higher concentrations of SO2, NOx, and O3 were recorded, attributed to local industrial and traffic emissions.

The annual total dry deposition was higher in urban areas, with sites like Chongqing (China) and Jakarta exhibiting the most significant deposition fluxes due to the proximity to major pollution sources.

Soil and Vegetation
Soil and vegetation health were monitored across sites like Ulaanbaatar (Mongolia) and Hanoi (Vietnam), where acid deposition was found to significantly alter soil pH, leading to lower nutrient availability and reduced plant health. Vegetation showed signs of chlorosis, indicating damage from the acidic compounds.

Inland Aquatic Environment
Water quality in regions like Hanoi (Vietnam) and Listvyanka (Russia) was found to be significantly impacted by acid deposition, with increased acidity levels in the water bodies. This has the potential to disrupt aquatic ecosystems by affecting species diversity, water chemistry, and nutrient cycling.

Data Quality Assurance and Statistical Analysis
The ion balance (R1) and conductivity agreement (R2) statistics were calculated for all monitoring sites to assess the accuracy of the data. Most sites met the acceptable range for these checks, but several sites like Ulaanbaatar (Mongolia) and Metro Manila (Philippines) had flagged data due to poor sample collection or analytical errors.

The report also included calculations of data completeness, showing that sites had high compliance with the required data standards, though some sites exhibited gaps due to equipment failures or missed sampling events.

Statistical Summary
Weighted average concentrations for pollutants were calculated for each site, and wet deposition amounts were derived based on these values.

Monthly and annual summary tables were provided for each site, detailing the pollutant levels, deposition amounts, and data completeness.

R1 and R2 checks for ion balance and conductivity agreement were visualized in plots for each site, with most sites meeting the required thresholds.

Conclusions and Future Directions
The 2009 Data Report confirms that acid deposition remains a significant environmental issue in East Asia, with varying impacts across regions. The findings highlight the need for ongoing monitoring, improved data quality, and expanded coverage to assess the long-term effects of acid deposition on ecosystems and human health.

Data completeness and accuracy were generally high, but continuous improvement in monitoring methods is required.

Expansion of monitoring sites to cover more sensitive areas, particularly in rural and remote regions, is recommended to better understand the full scope of acid deposition effects.

Further regional cooperation is necessary to refine methodologies and harmonize data collection processes across the participating countries.

The EANET continues to play a critical role in understanding and addressing the challenges posed by acid deposition in East Asia.