Introduction to the special issue “In-depth study of air pollution sources and processes within Beijing and its surrounding region (APHH-Beijing)”

Shi, Zongbo; Vu, Tuan V.; Kotthaus, Simone; Harrison, Roy M.; Grimmond, Sue; Yue, Siyao; Zhu, Tong; Lee, James; Han, Yiqun; Demuzere, Matthias; Dunmore, Rachel E.; Ren, Lujie; Liu, Di; Yuan-lin, Wang; Wild, Oliver; Allan, J. D.; Acton, W. Joe F.; Barlow, Janet F.; Barratt, Benjamin; Beddows, D. C. S.; Bloss, William J.; Calzolai, Giulia; Carruthers, David; Carslaw, David C.; Chan, Queenie; Chatzidiakou, Lia; Chen, Yang; Crilley, Leigh R.; Coe, Hugh; Dai, Tie; Doherty, Ruth M.; Duan, Fengkui; Fu, Pingqing; Ge, Baozhu; Ge, Maofa; Guan, Daobo; Hamilton, Jacqueline F.; He, Kebin; Heal, Mathew R.; Heard, D. E.; Hewitt, C. Nicholas; Hollaway, Michael; Hu, Min; Ji, Dongsheng; Jiang, Xujiang; Jones, R. L.; Kalberer, Markus; Kelly, Frank J.; Kramer, Louisa J.; Langford, B.; Lin, Chun; Lewis, Alastair C.; Li, Jie; Li, Weijun; Liu, Huan; Liu, Junfeng; Loh, Miranda; Lu, Keding; Lucarelli, F.; Mann, G. W.; McFiggans, G.; Miller, Mark R.; Mills, G.; Monk, Paul; Nemitz, Eiko; O’Connor, Fiona M.; Ouyang, Bin; Palmer, Paul I.; Percival, Carl J.; Popoola, Olalekan; Reeves, Claire E.; Rickard, Andrew R.; Shao, Longyi; Shi, Guangyu; Spracklen, Dominick V.; Stevenson, David S.; Sun, Yele; Sun, Zhiwei; Tao, Shu; Tong, Shengrui; Wang, Qingqing; Wang, Wenhua; Wang, Xinming; Xue-jun, Wang; Wang, Zifang; Wei, Lianfang; Whalley, Lisa K.; Wu, Xuefang; Wu, Zhijun; Xie, Pinhua; Yang, Fumo; Zhang, Qiang; Zhang, Yanli; Zhang, Yuanhang; Zheng, Mei

doi:10.5194/acp-19-7519-2019

Cited by 107 publications

(112 citation statements)

References 107 publications

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“…The measurements in Beijing formed part of "Air Pollution and Human Health in a Chinese Megacity", APHH-Beijing, which is a joint UK-China programme addressing air quality in Beijing (Shi et al, 2019). The measurements took place at the Chinese Academy of Science Institute of Atmospheric Physics (IAP) tower campus (39.9735 • N, 116.3723 • E), located in the northern suburbs of Beijing.…”

Section: Beijing Chinamentioning

confidence: 99%

Effect of aerosol composition on the performance of low-cost optical particle counter correction factors

et al. 2020

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Abstract. There is considerable interest in using low-cost optical particle counters (OPCs) to supplement existing routine air quality networks that monitor particle mass concentrations. In order to do this, low-cost OPC data need to be comparable with particle mass reference instrumentation; however, there is currently no widely agreed upon methodology to accomplish this. Aerosol hygroscopicity is known to be a key parameter to consider when correcting particle mass concentrations derived from low-cost OPCs, particularly at high ambient relative humidity (RH). Correction factors have been developed that apply κ-Köhler theory to correct for the influence of water uptake by hygroscopic aerosols. We have used datasets of co-located reference particle measurements and low-cost OPC (OPC-N2, Alphasense) measurements, collected in four cities on three continents, to explore the performance of this correction factor. We provide evidence that the elevated particle mass concentrations, reported by the low-cost OPC relative to reference instrumentation, are due to bulk aerosol hygroscopicity under different RH conditions, which is determined by aerosol composition and, in particular, the levels of hygroscopic aerosols (sulfate and nitrate). We exploit measurements made in volcanic plumes in Nicaragua, which are predominantly composed of sulfate aerosol, as a natural experiment to demonstrate this behaviour in the ambient atmosphere; the observed humidogram from these measurements closely resembles the calculated pure sulfuric acid humidogram. The results indicate that the particle mass concentrations derived from low-cost OPCs during periods of high RH (>60 %) need to be corrected for aerosol hygroscopic growth. We employed a correction factor based on κ-Köhler theory and observed that the corrected OPC-N2 PM2.5 mass concentrations were within 33 % of reference measurements at all sites. The results indicated that a κ value derived in situ (using suitable reference instrumentation) would lead to the most accurate correction relative to co-located reference instruments. Applying a κ values from the literature in the correction factor also resulted in improved OPC-N2 performance, with the measurements being within 50 % of the reference values. Therefore, for areas where suitable reference instrumentation for developing a local correction factor is lacking, using a literature κ value can result in a reasonable correction. For locations with low levels of hygroscopic aerosols and low RH values, a simple calibration against gravimetric measurements (using suitable reference instrumentation) would likely be sufficient. Whilst this study generated correction factors specific for the Alphasense OPC-N2 sensor, the calibration methodology developed is likely amenable to other low-cost PM sensors.

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Section: Beijing Chinamentioning

confidence: 99%

Effect of aerosol composition on the performance of low-cost optical particle counter correction factors

et al. 2020

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“…Z 0 and minimum L MO values of 0.5 and 30 m, respectively, represent conditions at the meteorological measurement site. However, greater Z 0 and minimum L MO values of 1.5 and 100 m, respectively, typical of urban areas dominated by densely packed tall buildings and concrete surfaces (Stewart and Oke, 2012), are used across the modelling domain and displace the upwind vertical wind speed, wind direction and turbulence profiles derived from the meteorological measurements.…”

Section: Emission Sources Meteorological Inputs and Surface Parametersmentioning

confidence: 99%

Street-scale air quality modelling for Beijing during a winter 2016 measurement campaign

et al. 2020

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Abstract. We examine the street-scale variation of NOx, NO2, O3 and PM2.5 concentrations in Beijing during the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China) winter measurement campaign in November–December 2016. Simulations are performed using the urban air pollution dispersion and chemistry model ADMS-Urban and an explicit network of road source emissions. Two versions of the gridded Multi-resolution Emission Inventory for China (MEIC v1.3) are used: the standard MEIC v1.3 emissions and an optimised version, both at 3 km resolution. We construct a new traffic emissions inventory by apportioning the transport sector onto a detailed spatial road map. Agreement between mean simulated and measured pollutant concentrations from Beijing's air quality monitoring network and the Institute of Atmospheric Physics (IAP) field site is improved when using the optimised emissions inventory. The inclusion of fast NOx–O3 chemistry and explicit traffic emissions enables the sharp concentration gradients adjacent to major roads to be resolved with the model. However, NO2 concentrations are overestimated close to roads, likely due to the assumption of uniform traffic activity across the study domain. Differences between measured and simulated diurnal NO2 cycles suggest that an additional evening NOx emission source, likely related to heavy-duty diesel trucks, is not fully accounted for in the emissions inventory. Overestimates in simulated early evening NO2 are reduced by delaying the formation of stable boundary layer conditions in the model to replicate Beijing's urban heat island. The simulated campaign period mean PM2.5 concentration range across the monitoring network (∼15 µg m−3) is much lower than the measured range (∼40 µg m−3). This is likely a consequence of insufficient PM2.5 emissions and spatial variability, neglect of explicit point sources, and assumption of a homogeneous background PM2.5 level. Sensitivity studies highlight that the use of explicit road source emissions, modified diurnal emission profiles, and inclusion of urban heat island effects permit closer agreement between simulated and measured NO2 concentrations. This work lays the foundations for future studies of human exposure to ambient air pollution across complex urban areas, with the APHH-China campaign measurements providing a valuable means of evaluating the impact of key processes on street-scale air quality.

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“…Sampling was performed as part of the Air Pollution and Human Health in a Developing Megacity (APHH-Beijing) campaign, a large international collaborative project examining emissions, processes, and health effects of air pollution. For a comprehensive overview of the programme, see Shi et al (2019). All sampling was conducted across a 1-month period at the Institute for Atmospheric Physics (IAP), Chinese Academy of Sciences, Beijing (39 • 58.53 N, 116 • 22.69 E).…”

Section: Sampling Sitementioning

confidence: 99%

“…Measurements of the classical air pollutants were measured at the same site and have been reported in the campaign overview paper (Shi et al, 2019). SO 2 was measured using a 43i SO 2 analyser (Thermo Fisher Scientific, USA), O 3 with a 49i O 3 analyser (Thermo Fisher Scientific, USA), and NO x with a 42i-TL trace NO x analyser (Thermo Fisher Scientific, USA) and a T500U CAPS NO 2 analyser (Teledyne API, USA).…”

Section: Other Measurementsmentioning

confidence: 99%

Observations of highly oxidized molecules and particle nucleation in the atmosphere of Beijing

et al. 2019

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Abstract. Particle nucleation is one of the main sources of atmospheric particulate matter by number, with new particles having great relevance for human health and climate. Highly oxidized multifunctional organic molecules (HOMs) have been recently identified as key constituents in the growth and, sometimes, in initial formation of new particles. While there have been many studies of HOMs in atmospheric chambers, flow tubes, and clean environments, analyses of data from polluted environments are scarce. Here, measurements of HOMs and particle size distributions down to small molecular clusters are presented alongside volatile organic compounds (VOCs) and trace-gas data from a campaign in June 2017, in Beijing. Many gas-phase HOMs have been characterized and their temporal trends and behaviours analysed in the context of new particle formation. The HOMs identified have a degree of oxidation comparable to that seen in other, cleaner, environments, likely due to an interplay between the higher temperatures facilitating rapid hydrogen abstractions and the higher concentrations of NOx and other RO2⚫ terminators ending the autoxidation sequence more rapidly. Our data indicate that alkylbenzenes, monoterpenes, and isoprene are important precursor VOCs for HOMs in Beijing. Many of the C5 and C10 compounds derived from isoprene and monoterpenes have a slightly greater degree of average oxidation state of carbon compared to those from other precursors. Most HOMs except for large dimers have daytime peak concentrations, indicating the importance of OH⚫ chemistry in the formation of HOMs, as O3 tends to be lower on days with higher HOM concentrations; similarly, VOC concentrations are lower on the days with higher HOM concentrations. The daytime peaks of HOMs coincide with the growth of freshly formed new particles, and their initial formation coincides with the peak in sulfuric acid vapours, suggesting that the nucleation process is sulfuric-acid-dependent, with HOMs contributing to subsequent particle growth.

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Introduction to the special issue “In-depth study of air pollution sources and processes within Beijing and its surrounding region (APHH-Beijing)”

Cited by 107 publications

References 107 publications

Effect of aerosol composition on the performance of low-cost optical particle counter correction factors

Effect of aerosol composition on the performance of low-cost optical particle counter correction factors

Street-scale air quality modelling for Beijing during a winter 2016 measurement campaign

Observations of highly oxidized molecules and particle nucleation in the atmosphere of Beijing

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