Same view during clear sky conditions. Images courtesy of Ru-Jin Huang
View of the City of Xi'an during a strong pollution episode in 2014.
Scope of project
Air pollution in Chinese cities is one of the environmental problems China has to address to mitigate the impacts on human health, air quality and climate. Average concentrations of particulate matter exceed 100 μg/m3 in many places in China, and the government is developing and implementing strategies to reduce the load of pollutants by various measures. A characterization of airborne particulate matter (PM), especially its composition and sources, will help in optimizing reduction and mitigation strategies for air pollution.
The project aims at studying the temporal variation of major component and trace element concentrations in airborne particulate matter (PM) and their sources in one megacity in China (People’s Republic of China, PRC) and one megacity in India. Statistical source apportionment techniques will be applied to data collected during a fall field campaign in Beijing and a winter campaign in New Delhi. Ambient aerosols will be sampled with 3-stage rotating drum impactors (RDI) segregating the aerosol into the size classes 10-2.5 μm, 2.5 – 1.0 μm, 1.0 – 0.1 μm, in combination with black carbon measurements with aethalometers. The samples are analyzed with synchrotron radiation induced X-ray fluorescence spectrometry (SR-XRF), which yields concentration time series for more than 20 elements (Na to Pb). Pairwise sampling (two RDI/aethalometer combinations at two sites in the same city) will allow for the identification of local and regional pollution, long-range transport, urban increments, and other PM characteristics. The 60-min time resolution allows for the quantitative analysis of diurnal and weekly variations of PM concentrations. An switching system allows for alternating collection of PM10 and PM2.5. Combination of trace elements with aethalometer black carbon and 14C promises to improve the identification of coal combustion, traffic and other industrial sources by their fossil/non-fossil characteristics. Trace elements combined with organics from aerosol mass spectrometry improves the source apportionment of organics in PM.
The project aims at studying the temporal variation of major component and trace element concentrations in airborne particulate matter (PM) and their sources in one megacity in China (People’s Republic of China, PRC) and one megacity in India. Statistical source apportionment techniques will be applied to data collected during a fall field campaign in Beijing and a winter campaign in New Delhi. Ambient aerosols will be sampled with 3-stage rotating drum impactors (RDI) segregating the aerosol into the size classes 10-2.5 μm, 2.5 – 1.0 μm, 1.0 – 0.1 μm, in combination with black carbon measurements with aethalometers. The samples are analyzed with synchrotron radiation induced X-ray fluorescence spectrometry (SR-XRF), which yields concentration time series for more than 20 elements (Na to Pb). Pairwise sampling (two RDI/aethalometer combinations at two sites in the same city) will allow for the identification of local and regional pollution, long-range transport, urban increments, and other PM characteristics. The 60-min time resolution allows for the quantitative analysis of diurnal and weekly variations of PM concentrations. An switching system allows for alternating collection of PM10 and PM2.5. Combination of trace elements with aethalometer black carbon and 14C promises to improve the identification of coal combustion, traffic and other industrial sources by their fossil/non-fossil characteristics. Trace elements combined with organics from aerosol mass spectrometry improves the source apportionment of organics in PM.
Field campaigns
Beijing Fall 2017
A field campaign has taken place from 25 September through 15 December 2017. For metals measurements, an Xact 625i and two RDI were deployed at two sites in and near Beijing.New Delhi, India, Winter 2018
A field campaign has taken place from 05 January through 07 March 2018. Here only the Xact 625i was in operation at the Indian Institute for Technology, New Delhi.New Delhi, India, Winter 2019
A field campaign has taken place from 01 January through 08 February 2019. Here the Xact 625i was in operation at the Indian Institute for Technology, New Delhi, from 11 Jan to 8 Feb 2019.Key findings
Funding
Swiss National Science Foundation SNSF Grant 200021_162448/1
Publications
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Furger M, Minguillón MC, Yadav V, Slowik JG, Hüglin C, Fröhlich R, et al.
Elemental composition of ambient aerosols measured with high temporal resolution using an online XRF spectrometer
Atmospheric Measurement Techniques. 2017; 10(6): 2061-2076. https://doi.org/10.5194/amt-10-2061-2017
DORA PSI -
Furger M, Rai P, Slowik JG, Cao J, Visser S, Baltensperger U, et al.
Automated alternating sampling of PM10 and PM2.5 with an online XRF spectrometer
Atmospheric Environment: X. 2020; 5: 100065 (6 pp.). https://doi.org/10.1016/j.aeaoa.2020.100065
DORA PSI -
Rai P, Furger M, El Haddad I, Kumar V, Wang L, Singh A, et al.
Real-time measurement and source apportionment of elements in Delhi's atmosphere
Science of the Total Environment. 2020; 742: 140332 (16 pp.). https://doi.org/10.1016/j.scitotenv.2020.140332
DORA PSI -
Puthussery JV, Singh A, Rai P, Bhattu D, Kumar V, Vats P, et al.
Real-time measurements of PM2.5 oxidative potential using a dithiothreitol assay in Delhi, India
Environmental Science and Technology Letters. 2020; 7(7): 504-510. https://doi.org/10.1021/acs.estlett.0c00342
DORA PSI