Vehicle-related ammonia emissions in Hong Kong
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Weekly passive sampling of ambient ammonia has been performed at ground or rooftop levels at 12 locations in Hong Kong representing different land use categories. The highest weekly average roadside level of ammonia in Hong Kong was 7.1 μg m−3 at a street canyon site. Ambient ammonia concentrations for a rooftop urban-residential site with nearby light traffic were <1 μg m−3, being less than at an adjacent road and indoor car-park. Rooftop levels of ammonia showed a significant correlation with nitrogen monoxide concentrations. Honeycomb denuder samplings were also carried out at the rooftop site and the results were consistent with passive sampling. It is concluded that the 0.54 M vehicles in Hong Kong make a considerable contribution to ambient ammonia concentrations, which are otherwise low.
KeywordsAmmonia emissions Passive sampling Honeycomb denuder Catalytic converter Asia
This work was supported by the City University Strategic Research Grant 7001762. I thank Dr. S.C. Lee and Ms. M.C. Yeung for carrying out the sampling and analyses in this project. Permission to sample at Hong Kong EPD monitoring sites and the receipt of ambient NO data are duly acknowledged with thanks.
- USEPA (1999) Compendium of methods for the determination of inorganic compounds in ambient air, chap IO-4. Report EPA-625/R-96/010aGoogle Scholar