Emission strengths for primary pollutants as estimated from an aircraft study of Hong Kong air quality

An aircraft study of air quality in the Hong Kong region during the fall of 1994 has allowed for an estimation of the daytime source strengths for CO and NO_y from the Hong Kong metropolitan center. Emission rate estimates for the Hong Kong urban plume for NO_y and CO were 5.4×10e(25) molecules s^-1 and 1.8×10e(26) molecules s^-1 as determined for the case study of 18 October. All emission rate estimates have uncertainties of a factor of 2. On one occasion a distinct plume emanating from Shenzhen in the People’s Republic of China was encountered. While plume delimitation was insufficient for source strength calculations, transect integrals did allow for a CO/NO_y ratio of about 16 to be determined. The CO/NO_y ratio for the Hong Kong urban plume was about 3.3. The difference in these ratios indicates differences in the overall combustion processes and efficiencies taking place within Hong Kong and the PRC.