Aiming to enhance air quality monitoring capacity and better provide air pollution information in real-time, in 2013 the EPA launched the New-Generation Environmental Quality Monitoring and Testing Development Plan. Under the program, the air quality monitoring network has been upgraded into its fourth generation, resulting in much-improved air quality. Other than upgrades in hardware such as equipment in national-level monitoring stations, the EPA will keep strengthening the real-time broadcast and notification mechanism and working with the Central Weather Bureau (CWB) to enhance its air quality forecast operations and services.
Air quality in Taiwan has shown significant improvement based on the EPA’s annual air quality monitoring report. Comparing data collected by monitoring stations in 2020 with that collected during the past decade, average annual concentrations of major air pollutants being monitored in 2020, such as particulate matters, fine particulate matters (PM2.5), sulfur dioxide (SO2), nitrogen dioxide, and ozone, are lower than concentrations in 2019.
Air quality monitoring is the key foundation for protecting air quality and controlling air pollution. The establishment of an air quality monitoring network went through three generations between 1980 and 2013. Significant steps taken during that period include the National Air Quality Monitoring Network Establishment Plan in 1993 and the Environmental Quality Monitoring Network Phasing Plan in 2005.
The New-Generation Environmental Quality Monitoring and Testing Development Plan was launched in 2013 in response to climate change and to meet the public demand for information on air quality. Through it, the EPA has hoped to further enhance national capacity in air quality monitoring, better provide air pollution information in real-time, and develop the fourth generation of the air quality monitoring network.
The new-generation air quality monitoring system strives to achieve four goals: integration of central and regional monitoring capacity; strengthening of pollutant concentration testing capacity; enhancing understanding and handling of regional pollution incidents, and; improving real-time environmental monitoring data broadcasting mechanisms. Significant measures include integrating all types of national monitoring resources under the EPA’s global information website (http://airtw.epa.gov.tw/), providing assistance, phasing out of obsolete or old instruments in national-level monitoring stations, establishing a multi-layered air quality monitoring Internet of Things (IoT), and adding standard manual methods for PM2.5 as well as a monitoring network for chemical compounds.
For the data collection systems of monitoring stations and the air quality monitoring center database, the EPA has also enhanced real-time broadcasting and notification mechanisms and works with the CWB to fine-tune operations and services related to air quality forecasts.
Monitoring instruments, such as the automated ones for PM2.5, that have been upgraded under the New-Generation Environmental Quality Monitoring and Testing Development Plan will no longer undergo calibration based on linear regression. This is because the instruments have already passed the USEPA’s similarity standard methods, as well as meeting the similarity requirements listed in Taiwan’s Regulations Concerning Comparisons Between Manual and Automated In-Air PM2.5 Testing Methods (空氣中細懸浮微粒手動及自動檢測方法比對規範).
In response to making yearly air quality improvement, in the future, instruments in national-level monitoring stations will undergo upgrades on precision and limits will become more stringent so as to meet environmental monitoring needs concerning low-concentration pollutants. It is hoped this will provide the better information and high-quality monitoring data services needed to formulate control strategies.
Focuses of recent air quality monitoring
Recent air quality monitoring has been focusing on the following two aspects:
1. Strengthening monitoring capacity for low-concentration pollutants
To meet future needs to monitor air pollutants at lower concentrations, the EPA is paying special attention to the low-concentration monitoring capacity of instruments as they are upgraded. Specification improvements have included the removal of vapor disruption, which effectively led to the setting of record-low detection limits. For instance, instruments can now detect sulfur dioxide as low as 0.3 ppb as opposed to 0.5 ppb previously (a drop in the lower detection limit by 40%), 0.4 ppb of nitrogen oxides as opposed to 0.5 ppb previously (a 20% drop), and 0.5 ppb of ozone as opposed to 1 ppb previously (a 50% drop). These all demonstrate a significant leap in the monitoring capacity of instruments.
2. Integrating capacity of central and regional monitoring networks
The EPA has developed an integrated national air quality system, which collects and combines data from 218 monitoring stations in Taiwan. They include the EPA’s own 78 stations, 34 stations belonging to regional environmental bureaus, 36 stations belonging to specialized industrial parks, and 70 to large-scale enterprises. In addition, there have been continual efforts in assisting and expanding the collection of data from monitoring stations of other large-scale enterprises. The purpose is to improve comprehensive services to the public including real-time air quality information by facilitating integration of all monitoring stations across Taiwan.
3. Handling of regional pollution incidents
In order to get the complete picture of the impacts on air quality from regional environmental atmospheric changes, the EPA has built a LIDAR (light detection and ranging) network. The network can monitor altitudes of diffusion layers in the atmosphere in areas prone to poor air dispersion. Another monitoring network has been set up with sensors for long distance visibility and particle size analyzers, so as to simultaneously monitor both visibility and particle sizes and analyze the correlation between visibility and air quality. Core monitoring stations comprising LIDAR, visibility sensors, particle size analyzers, and facilities that monitor PM2.5 components have been set up in three regions to analyze pollution characteristics for future reference. These locations are: Banqiao, New Taipei City, in the northern region; Xitun, Taichung City, in the central region, and; Xiaogang, Kaohsiung, in the southern region.
Replacing and upgrading instruments used in the monitoring network
Significant achievements in the work of replacing and upgrading monitoring network equipment include:
(1) A better understanding of regional pollution characteristics
To enhance the quality of the national-level air quality monitoring network, the EPA has set up a background monitoring station in Fugui Cape, added six mobile monitoring stations, three mobile photochemical assessment stations, and one stationary station to assess photochemical reactions. Another significant advance was the establishment of the LIDAR monitoring network and set up of optical monitoring bases in the northern, central, and southern regions. Moreover, the EPA has been working on enhancing data collection and transmission management systems. By-the-hour data checking and equipment status analysis are now automated, effectively optimizing data collection and reading.
(2) New equipment for better environmental analysis
As air quality has improved year after year, there has been a growing need for low-concentration pollution monitoring. Thus, the EPA has replaced old equipment with new, including 90 new analyzers for sulfur dioxide, 90 for nitrogen oxides, 90 for ozone, 80 zero air generators, and 80 gas dilution calibrators. In total, the replacement and upgrades consisted of 1,286 instruments under 35 categories, 26 operation rooms under four types, and two vehicles for quality maintenance and audits. They can all be operated with higher stability and lower malfunction rates, with enhanced performance and 20-50% improvement in their capacity for detecting low concentrations of pollutants.
Future work and expected results
The following are focuses and expected results of future air quality monitoring:
1. Establishing the new-generation air quality monitoring network
With low-concentration pollution more and more common, the EPA will continue to upgrade equipment, enhance detection capacity and removal of interfering data, and lower detection limits. Another focus is to lay the foundation for telecommunications for monitoring in the age of Industry 4.0.
2. Improving understanding of regional pollution characteristics
The EPA will be able to better understand regional pollution incidents and, in turn, improve in issuing forecasts and warnings by enhancing its capacity to monitor atmospheric characteristics.
3. Enhancing analysis capacity with new equipment
Multiple types of environmental quality monitoring and testing equipment have been introduced to better analyze pollution characteristics in the future.
4. Improving environmental monitoring information services
The EPA is able to provide better information services to over 20 million viewers every year after upgrading its information system's hardware and software.
Excerpt from Major Environmental Policies, Apr 2021
- Environmental Protection Administration, R.O.C.(Taiwan)