(1) Environmental load and trends
End of February 2022, the population of Tainan City was 1.859 million, with a density of 848.1 people/km2, which was higher than national average 644 people/km2, ranking sixth among the six municipalities, and the population has shown a downward trend since 2018.
There are currently a total of 2,434 controlled-list factories in Tainan City, of which plastic products manufacturers account for the largest number (about 17%), followed by the metal industry (about 13%), and then the gas station industry (about 11%). In recent years, the number of construction sites has generally shown an increasing trend year by year, with approximately 12,000-13,000 sites each year.
The total number of vehicles was 2.061 million in February 2022, and the number of vehicles for per person was 1.1, of which scooters account for the majority (65.2%), followed by automobiles for 29.6% and diesel trucks for 5%. The scooter is negative growth, especially the two-stroke scooters have decreased 85.5% from 2013 to February 2022, and the electric scooters have gradually exceeded the two-stroke scooters since 2021. However, the fuel and diesel supply has increased by 7.1% in the past decade.
(2) Air quality analysis
In general, the ratio of air quality index (AQI) of good and ordinary grades (AQI ≤ 100) in Tainan City in the past five years (2017~2021) has shown an increasing trend year by year, rising from 72% in 2017 to 82.9% in 2021, and has exceeded 80% for two consecutive years, and the number of good days reached a record high of 40.6%. The rate of poor air quality index (AQI>100) has shown a trend of improvement year by year, from 28.4% in 2017 to 17.1% in 2021, and the rate of poor AQI has decreased by 40%. Among them, the improvement of PM2.5 was the most significant, from 20.1% in 2017 to 12.1% in 2021; O3 -8hr shows a fluctuating trend, however, O3-8hr has improved significantly and the poor air quality ratio was 4.93%, reaching a record low, and there were no red station days.
From January to March 2022, the ratio of poor air quality (AQI>100) was 20.6%, showing an improvement trend compared with 45.7% in the same period last year, a decrease of 25.1%.
In the trend of changes in the concentration of major air pollutants in the past 5 years (2017-2021), the annual average and daily average concentrations of PM10 have been improving year by year. The annual average has improved from 56.6 μg/m3 in 2017 to 39.2 μg/m3 in 2021, with an improvement rate of 25.4%; the daily average has improved from 113.6 μg/m3 in 2017 to 98.6μg/m3 in 2021, an improvement rate of 13.2%, and have also met the newly revised air quality standards (50μg/m3, 100μg/m3) for three consecutive years since 2019. As of March 2011, the annual average of PM10 was 42.8μg/m3, a significant improvement of 32% compared with 63.25μg/m3 in the same period last year, and the daily average was 83.1μg/m3, a significant improvement of 24% compared with 109.4μg/m3 in the same period last year.
The annual average and 24-hour average concentration of PM2.5 by manual measurement stations are improving year by year. The annual average has dropped from 24 μg/m3 in 2017 to 18.6 μg/m3 in 2021, with an improvement rate of 22.3%; the 24-hour average decreased from 73 μg/m3 in 2017 to 69.8 μg/m3 in 2021, and the improvement rate was 17.7%.
The hourly average and 8-hour average concentrations of O3 show fluctuations, but the overall trend is still decreasing. The hourly average improved 0.2% and declined from 91.5 ppb in 2017 to 91.4 ppb in 2021；8-hour average improved 4.3% and declined from 73 ppb in 2017 to 69.8 ppb in 2021.
(3) Analysis for emission inventory
According to the TEDS 11.0 emissions database and the updated results of this plan, each category of emission sources in Tainan in 2019 are below:
Category TSP PM10 PM2.5 SOx NOx NMHC
Point (tons/year) 739.61 501.33 384.25 1,214.52 2,618.71 3,461.53
Area (tons/year) 40,992.79 11,868.16 2,924.23 325.65 1,505.54 27,875.50
Line (tons/year) 2,958.27 2,040.67 1,634.76 10.91 17,717.92 9,155.20
Total emission(tons/year) 44,690.68 14,410.17 4,943.24 1,551.08 21,842.17 42,202.12
According to the emission inventory in 2019 to analyze the trend of emission changes in the past ten years. Compared with 2010, TSP and PM10 increased by 12% and 1% respectively; while PM2.5, SOx, NOx and NMHC decreased by 18%, 65%, 20% and 8% respectively.
(4) Management Examination Tainan City Air Pollution Control Plan (2020~2023)
Assisted the Tainan City Environmental Protection Bureau (TNEPB) in administering the Tainan City Air Pollution Control Plan (2020 to 2023), with a total of three aspects, 27 control strategies, 60 control goals, and the "Bright Clear Sky Suspended Particulate Reduction Control Plan" for the cross-bureau. The main focus of this edition of the paln is the annual average concentration target of PM2.5 and the reduction target of air pollutants.
Based on the achievement of the annual average concentration target of PM2.5 in Air Quality Basin, the average annual concentration of PM2.5 in Yun-Jia-Nan Air Quality Basin in 2021 was 19.63 µg/m³, which has reached the expected target of 20.5 µg/m³; in terms of pollutant reduction targets, various air pollutants (PM10, PM2.5, SOx, NOx and NMHC) have all reached the planning targets ahead of schedule.
(5) Manage the quality and effectiveness in each air quality control project
1. Executing “2021 Tainan City Air Quality Improvement and Maintenance Plan Management and Evaluation Method”: SIP assisted TNEPB to evaluate the quality and effectiveness of each air quality relative projects.
2. Managements results of each air quality relative projects: “Strengthen the Street Dust Cleaning project” had the highest scores because of the completeness of data reporting and the achievement of Air Pollution Control Plan with high scores. The other hand, “Scooter Exhaust Pollution Inspection and Control Project” had the poor scores because of the goal of Air Pollution Control Plan and the work progress of the EPA's assessment are behind schedule, which affects the overall performance.
3. Grasps the contents of the performance evaluation work of the EPA's air quality improvement work in 2021, and considers the implementation capacity of the relevant committees in the Air Noise Section of TNEPB, and evaluates the estimated score in 2021 of Tainan City’s evaluation of about 99.44 points, and the overall score the rate is 88%.
(6) Operation and maintenance of TN EPB automatic and manual monitoring stations
1. According to the requirements of the project contract, 132 sampling for TSP, 11 sampling for component analysis of TSP, 22 dust fall sampling, 132 single-point flow calibrations, 24 multi-point flow calibrations, 1-type first-level flow calibrations, 1 timer calibration and 6-point precision testing for the manual station were completed as scheduled. In terms of the automatic station, 12 station-times monthly maintenance, 6 station-times quarterly maintenance and 2 station-times semi-annual maintenance were completed as scheduled.
2. In the part of the data utilization rate of the automatic monitoring station, the overall data availability rate reached 99.7%, except for a few periods of time due to equipment failure and inaccessibility of the equipment in the school.
(7) Maintenance and management of air quality purification zone
1. The number of air quality purification zone sites increased from 192 in 2011 to 236 in March 2022, a total of 44 sites have been added, with a total area of 76.974 hectares and a length of 73.378 kilometers.
2. In 2021, the total of applications for subsidies were 6 places. After review, the approved application area was 0.329 hectares, and the approved amount was NT$593,252. In addition, a total of 135 purification zone sites applied for maintenance subsidies, with an application rate of 77.5% and an approved amount of NT$2,792,180.
3. In 2021, a total of 226 purification zone bases were assessed. The assessment opinions were fed back to the maintenance units on the bulletin board through the front desk system function of the Tainan Air Quality Purification District website..
4. Assisted in submitting 7 excellent purification zones to participate in the EPA's "Selection and Reward Activity for Excellent Adopting Units in Air Quality Purification Zones". The EPA and experts and scholars conducted an on-site inspection in Tainan City on September 30, 2021. In the end, 6 adoption units won awards, and the TNEPB also won the "Outstanding Performance" award.
5. Completed the adoption of 30 purification zones by enterprises, village offices, community development associations, school parent associations or volunteer teams; in addition, completed the diagnosis and treatment of 5 purification zones to achieve the work goals of this year.
6. Assisting 1 junior high school to apply for setting green wall from EPA, with a total installation area of 28 m2. In addition, in 2022, the campus green wall will be promoted through the “Bright Clear Sky Project”, and there are 11 applications for green wall installation as of March 2022.
(8) Promotion for Air quality management effectiveness
1. In order to give the public a good impression of the policy and convey the air pollution policy, it is the first in the country to set up the "Tainan City Air Quality Monitoring Network" by this project, to provide a three-day air quality forecast in detail during the poor air season, and also publishes the air quality, weather pattern, wind speed and direction of the day, and other relevant information before am 7:30 every day for providing the public with complete air quality information in a convenient way. In addition, "air quality information display boards" have been set up in three places, including Wenhua village Community Activity Center in the Southern District, the TNEPB's Cangjin Pavilion (Fudong Street) and the Cangjin Pavilion Preparatory Office (Fuqian Road) to provide real-time air quality information for the outdoor public.
2. In order to understand the citizens' views on the air quality and the improvement work in Tainan City, a questionnaire survey was conducted on the citizens' satisfaction with the air quality improvement work through telephone interviews. According to the results of the questionnaire survey, the public thinks that the air quality in Tainan City is mainly caused by self-pollution emissions, and the main cause is the exhaust gas of factories, followed by the emissions from automobiles and motorcycles. Among the emissions from automobiles and motorcycles, the public believes that motorcycles are the main source of emissions; to improve the pollution caused by motorcycle, most people expressed their willingness to take the initiative to eliminate old motorcycles.
3. In order to make citizens feel good about the policy and convey that the city attaches great importance to air pollution-related policies, the EPB has been assisted by this project in issuing 16 press releases and 129 Facebook card posts.
4. Continue to maintain the 30 AQI information push and broadcast systems and Xiaoximen electronic billboards, and publish messages to promote public protection during poor air quality seasons to make air quality information disclosures more transparent.
5. During the season of poor air quality, 14 large-scale electronic billboards were rented at important intersections in Tainan City to remind the public of relevant protection messages, contingency measures for air quality deterioration, and promotion of various air pollution management policies of the TNEPB.
