IENV Brochure - Satellite Remote Sensing

SATELLITE REMOTE SENSING FRONTIER RESEARCH Source Identification & Policy Effectiveness Accessment SINCE

1999

RESEARCH Local/Regional air pollution hot spots identifications Regional pollution episodes transportation and dissipation patterns

2003

2017

Spatiotemporal distribution of PM2.5 in Mainland China and Hong Kong

High-resolution satellite remote sensing of provincial PM2.5 trends in China over 15-year time span

Remote sensing facilities - the HRPT (High Resolution Picture Transmission) station for the reception of SeaWiFS (Sea-viewing Wide Field-of-view Sensor) ocean color data - were installed at HKUST in 1994.

Since then, transmission data from NOAA (National Oceanic and Atmospheric Administration)-12, -14 satellites and the SeaStar satellite has been received for numerous environmental research purposes.

Coupling with advanced weather prediction models and simulation-/observation-based models, remote sensing technology has been demonstrating as a powerful tool to retrieve large scale spatiotemporal air pollution distribution patterns. It also empowers decision-makers with solid evidence to design effective and robust air pollution control policy frameworks.

FINDINGS / SIGNIFICANCE In 1999, very high Air Pollution Index (API) was recorded in Hong Kong due to wild fires events in Ching Ming Festival both in Hong Kong and Guangdong. In the later months of the same year, another ever-recorded high API events also occured in western part of Hong Kong.

By combining remote sensing technology and Numerical Weather Prediction (NWP) system results, air pollution hot spots in the region, as well as the movement and dissipation of the smoke and haze were also identified.

Since 2003, satellite remote sensing technology has been deployed to investigate large scale PM2.5 distribution across the region. The results are so important to improve our understanding about the sources of air pollution, hence enhancing the design of effective monitoring and control policies.

Advanced studies were conducted to fill the data gap of the lacking of long-term PM2.5 measurement from 2001 to 2005. The results provided evidence to justify the effectivenes of cooresponding air pollution prevention and control policies in different major city clusters in the Greater China.

© 2018 Institute for the Environment, HKUST

MILESTONES & POLICY IMPLICATIONS for HONG KONG Hong Kong / regional air quality management performance can be Regional collaboration on accessed by high-resolution long-term "Air Quality Forecast & Management" satellite remote sensing results IENV started using satellite remote sensing technologies to study air pollution distribution 2003

Guangdong-Hong Kong jointly developed the first national "Regional Air Quality Monitoring Network"

2005

National fixed-site monitoring of PM2.5 concentrations available in China

2013

SATELLITE REMOTE SENSING IN PRACTICE City Cluster comparisons Cluster A

Beijing-Tianjin-Hebei cluster

-1.02 μg/m 3 Cluster B

Jiangsu-Shejiang-Shang

-0.25 μg/m 3 Cluster C

Sichuan-Chongqing

-0.60 μg/m 3 Cluster D

Guangdon-HK-Macau Lin et al., 2018

-0.49 μg/m 3

Nationally, PM2.5 concentrations are declining in increasing rate, particularly since the issue of the Air Pollution Prevention & Control Action Plan (Plan) in 2013. The "Beijing-TianjinHebei cluster" has achieved the greatest rate of PM2.5 reduction.

However, such improvement seemed not to be fast enough to reach the Plan which aims to reduce PM2.5 concentration to 60 ug/m 3 by 2017. More stringent measurements (including studies in VOC reduction) have thus to be deployed to speed up air quality improvement.

In Hong Kong and other cities in the eastern or southeastern China where PM2.5 air qualities are greatly affected by other city clusters, collaboration with neighboring provinces is a must to achieve regional hence local air quality improvement breakthroughs.