 |
| Titel |
Wintertime aerosol chemistry and haze evolution in an extremely polluted city of North China Plain: significant contribution from coal and biomass combustions |
| VerfasserIn |
Haiyan Li, Qi Zhang, Qiang Zhang, Chunrong Chen, Litao Wang, Zhe Wei, Shan Zhou, Caroline Parworth, Bo Zheng, Francesco Canonaco, André Prévôt, Ping Chen, Hongliang Zhang, Kebin He |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138681
|
| Publikation (Nr.) |
 EGU/EGU2017-1781.pdf |
|
|
|
|
|
| Zusammenfassung |
| The North China Plain (NCP) frequently encountered heavy haze pollution in recent years,
particularly during wintertime. In 2015-2016 winter, the NCP region suffered several
extremely severe haze episodes with air pollution red alerts issued in many cities. In this
work, we investigated the sources and aerosol evolution processes of the severe pollution
episodes in Handan, a typical industrialized city in the NCP region, using real-time
measurements from an intensive field campaign during the winter of 2015-2016. The average
(± 1σ) concentration of submicron aerosol (PM1) during December 3, 2015 – February 5,
2016 was 187.6 (± 137.5) μg m−3, with the hourly maximum reaching 700.8 μg m−3.
Organic was the most abundant component, on average accounting for 45% of total PM1
mass, followed by sulfate (15%), nitrate (14%), ammonium (12%), chloride (9%) and BC
(5%). Positive matrix factorization (PMF) with multi-linear engine (ME-2) identified four
major organic aerosol (OA) sources, including traffic emissions represented by a
hydrocarbon-like OA (HOA, 7% of total OA), industrial and residential burning
of coal represented by a coal combustion OA (CCOA, 29% of total OA), open
and domestic combustion of wood and crop residuals represented by a biomass
burning OA (BBOA, 25% of total OA), and formation of secondary OA (SOA) in the
atmosphere represented by an oxygenated OA (OOA, 39% of total OA). Emissions
of primary OA (POA), which together accounted for 61% of total OA and 27%
of PM1, are a major cause of air pollution in this region during the winter. Our
analysis further uncovered that, primary emissions from coal combustion and biomass
burning together with secondary formation of sulfate (mainly from SO2 emitted by
coal combustion) are important driving factors for haze evolution. However, the
bulk composition of PM1 showed comparatively small variations between less
polluted periods (daily PM2.5 ≤ 75 μg m−3) and severely polluted periods (daily
PM2.5 > 75 μg m−3), indicating relatively synchronous increases of all aerosol
species during haze formation. The case study of a severe haze episode, which
lasted 8 days starting with a steady build-up of aerosol pollution followed by a
persistently high level of PM1 (326.7 – 700.8 μg m−3), revealed the significant
influences of stagnant meteorological conditions on acerbating air pollution problems in
the Handan region. The haze episode ended with a shift of wind which brought
in cleaner air masses from the northwest of Handan and gradually reduced PM1
concentration to < 50 μg m−3 after 12 hours. Furthermore, aqueous-phase reactions under
higher relative humidity (RH) were found to significantly promote the production of
secondary inorganic species (especially sulfate), but showed little influence on SOA. |
|
|
|
|
|
|