On August 7, Guangdong, Hong Kong and Macao jointly released the 2002 air quality report of the the Pearl River Delta Regional Air Monitoring Network of Guangdong, Hong Kong and Macao, which showed that the air quality in the the Pearl River Delta (PRD) region continued to improve. The regional air monitoring network was launched in November 2005, monitoring air pollution parameters including three types of air pollutants (sulfur dioxide, particulate matter PM10, and nitrogen dioxide) and one photochemical secondary air pollutant (ozone). In September 2014, monitoring of two types of air pollutants (carbon monoxide and particulate matter PM2.5) was added. All five air pollutants show a long-term downward trend (see Annex 1). Compared with 2006, the average annual concentrations of sulfur dioxide, particulate matter PM10, and nitrogen dioxide recorded in 2022 decreased by 86%, 52%, and 45%, respectively. Compared with 2015, the average annual concentrations of carbon monoxide and particulate matter PM2.5 recorded in 2022 decreased by 16% and 38% respectively; The average annual concentration of ozone in 2022 increased by 39% compared to 2006, indicating that the photochemical pollution in the region still needs improvement. The average annual concentration values of the six air pollutants mentioned above since 2006 are shown in Annex 2. To continuously improve regional air quality, the Hong Kong Special Administrative Region Government (HKSAR Government) and the Guangdong Provincial Government have been committed to reducing emissions from major air pollution sources. The governments of Guangdong and Hong Kong have completed the "Study on Regional Air Pollutant Emission Reduction Targets and Concentration Levels after 2020", setting the direction for future cooperation in addressing ozone issues. In addition, the study on photochemical ozone pollution and regional and cross regional transport characteristics in the Greater Bay Area is also underway to understand the sources of ozone precursors, the causes of ozone formation, and the characteristics of regional and cross regional transport in the Greater Bay Area, providing a scientific basis for formulating ozone control strategies. In terms of monitoring, the governments of Guangdong, Hong Kong, and Macao are researching and exploring the inclusion of routine monitoring of volatile organic compounds in regional air monitoring networks. In addition, the Hong Kong SAR government is actively preparing to build the Greater Bay Area Air Quality Laboratory and Meteorological Monitoring Super Station in Hong Kong, providing regional air pollution and meteorological monitoring and forecasting services. The Hong Kong SAR government has implemented multiple air pollutant emission control measures covering land and sea transportation, power plants, and non road mobile machinery to improve air quality. In 2021, it successively released the "Road Map for the Popularization of Electric Vehicles in Hong Kong", "Hong Kong Fresh Air Blueprint 2035", and "Hong Kong Climate Action Blueprint 2050", proposing various measures, Leading Hong Kong's efforts to achieve zero vehicle emissions and carbon neutrality by 2050. The Hong Kong SAR government is gradually implementing the measures proposed in the road map and blueprint, including promoting the use of electric vehicles and other new energy vehicles, green transportation, zero carbon energy, and other environmental measures, which will further improve the overall air quality of Hong Kong. The Hong Kong SAR government has also been adopting a multi-pronged strategy to reduce volatile organic compound emissions. The emissions of volatile organic compounds in Hong Kong have steadily decreased in response to various air pollutant reduction measures. To further promote this work, the Hong Kong SAR government has tightened and expanded the volatile organic compound content limits for 22 regulated building paints