Observation-based sources evolution of non-methane hydrocarbons (NMHCs) in a megacity of China.
J Environ Sci (China)
; 124: 794-805, 2023 Feb.
Article
em En
| MEDLINE
| ID: mdl-36182184
ABSTRACT
Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China, in contrast to the fact that an increase in emissions of non-methane hydrocarbons (NMHCs) has been reported. This study employed seven years continuous NMHCs measurements and the related activities data of Shanghai, a megacity in China, to explore evolution of emissions and effectiveness of air pollution control measures. The mixing ratio of NMHCs showed no statistical interannual changes, of which their compositions exhibited marked changes. This resulted in a decreasing trend of ozone formation potential by 3.8%/year (p < 0.05, the same below), which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime. Observed alkanes, aromatics and acetylene changed by +3.7%/year, -5.9%/year and -7.4%/year, respectively, and alkenes showed no apparent trend. NMHCs sources were apportioned by a positive matrix factorization model. Accordingly, vehicular emissions (-5.9%/year) and petrochemical industry emissions (-7.1%/year) decreased significantly, but the decrease slowed down; significant reduction in solvent usage (-9.0%/year) appeared after 2010; however, emissions of natural gas (+12.6%/year) and fuel evaporation (with an increasing fraction) became more important. The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions, emphasizing the need for further validation in NMHCs emission inventory. Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions, which provided new insights into future air policies in polluted region.
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Base de dados:
MEDLINE
Assunto principal:
Ozônio
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Poluentes Atmosféricos
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Compostos Orgânicos Voláteis
País/Região como assunto:
Asia
Idioma:
En
Revista:
J Environ Sci (China)
Assunto da revista:
SAUDE AMBIENTAL
Ano de publicação:
2023
Tipo de documento:
Article