Aerosol and boundary-layer interactions and impact on air quality

National Science Review, Journal Year: 2017, Volume and Issue: 4(6), P. 810 - 833

Published: Sept. 16, 2017

Abstract Air quality is concerned with pollutants in both the gas phase and solid or liquid phases. The latter are referred to as aerosols, which multifaceted agents affecting air quality, weather climate through many mechanisms. Unlike pollutants, aerosols interact strongly meteorological variables strongest interactions taking place planetary boundary layer (PBL). PBL hosting bulk of lower atmosphere affected by aerosol radiative effects. Both scattering absorption reduce amount solar radiation reaching ground thus sensible heat fluxes that drive diurnal evolution PBL. Moreover, can increase atmospheric stability inducing a temperature inversion result radiation, suppresses dispersion leads further increases concentration Such positive feedback especially strong during severe pollution events. Knowledge crucial for understanding between meteorology. A key question how interacts vertical directions, affects quality. We review major advances measurements, processes their each other complex mechanisms, highlight priorities future studies.

Language: Английский

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Relationships between the planetary boundary layer height and surface pollutants derived from lidar observations over China: regional pattern and influencing factors

Atmospheric chemistry and physics, Journal Year: 2018, Volume and Issue: 18(21), P. 15921 - 15935

Published: Nov. 7, 2018

Abstract. The frequent occurrence of severe air pollution episodes in China has been a great concern and thus the focus intensive studies. Planetary boundary layer height (PBLH) is key factor vertical mixing dilution near-surface pollutants. However, relationship between PBLH surface pollutants, especially particulate matter (PM) concentration across China, not yet well understood. We investigate this issue at ∼1600 stations using derived from space-borne ground-based lidar, discuss influence topography meteorological variables on PBLH–PM relationship. Albeit correlations are roughly negative for most cases, their magnitude, significance, even sign vary considerably with location, season, conditions. Weak or uncorrelated relationships found over clean regions (e.g., Pearl River Delta), whereas nonlinearly responses PM to evolution polluted North Plain). Relatively strong interactions when shallow high, which typically corresponds wintertime cases. Correlations much weaker highlands than plains regions, may be associated lighter loading higher elevations contributions mountain breezes. horizontal transport considered as well, manifested correlation wind speed whole nation. Strong upwind plays dominant role removing leads obscure relationships. A ventilation rate used jointly consider dispersion, largest impact pollutant accumulation Plain. As such, study contributes improved understanding aerosol–planetary (PBL) our ability forecast pollution.

Language: Английский

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Shift in the Temporal Trend of Boundary Layer Height in China Using Long‐Term (1979–2016) Radiosonde Data

Geophysical Research Letters, Journal Year: 2019, Volume and Issue: 46(11), P. 6080 - 6089

Published: May 24, 2019

Abstract The knowledge regarding how the boundary layer height (BLH) changes over time is still poor. Here we analyze spatial and temporal in radiosonde‐derived measurements of BLH China from 1979 to 2016. A qualitatively robust abrupt change occurred 2004. Over former period (from 2003) a spatially uniform increase was found BLH, while latter decreased nonuniform way. Second, meteorological influence on rising determined have negative association with soil moisture, lower tropospheric stability relative humidity, positive near‐surface temperature. Yet, there different meteorology period, where revealed T sfc humidity. These findings shed new light long‐term air pollution across China.

Language: Английский

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Interaction Between Planetary Boundary Layer and PM2.5 Pollution in Megacities in China: a Review

Current Pollution Reports, Journal Year: 2019, Volume and Issue: 5(4), P. 261 - 271

Published: Sept. 9, 2019

Abstract Purpose of Review During the past decades, number and size megacities have been growing dramatically in China. Most Chinese are suffering from heavy PM 2.5 pollution. In pollution formation, planetary boundary layer (PBL) plays an important role. This review is aimed at presenting current state understanding PBL-PM interaction megacities, as well to identify main gaps knowledge further research needs. Recent Findings The PBL critical formation urban multiple temporal scales, ranging diurnal change seasonal variation. For essential structure/process pollution, coastal different concerns mountainous or land-locked megacities. cities, recirculation induced by sea-land breeze can accumulate pollutants, whereas valley/basin, blocking effects terrains lead stagnant conditions thermal inversion. Within a megacity, although urbanization-induced land use cause thermodynamic perturbations facilitate development PBL, increases emissions outweigh this impact, resulting net increase aerosol concentration. Moreover, radiative modify heating upper layers reducing surface heat flux, suppressing exacerbating Summary presented 13 with various geographic elucidated influencing processes. To understand complicated interactions, long-term observations meteorology properties multi-layers need be implemented.

Language: Английский

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Trans-Pacific transport of dust aerosols from East Asia: Insights gained from multiple observations and modeling

Environmental Pollution, Journal Year: 2017, Volume and Issue: 230, P. 1030 - 1039

Published: July 27, 2017

Language: Английский

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On the Summertime Planetary Boundary Layer with Different Thermodynamic Stability in China: A Radiosonde Perspective

Journal of Climate, Journal Year: 2017, Volume and Issue: 31(4), P. 1451 - 1465

Published: Nov. 14, 2017

Abstract Strongly influenced by thermodynamic stability, the planetary boundary layer (PBL) is key to exchange of heat, momentum, and moisture between ground surface free troposphere. The PBL with different stability across whole China, however, not yet well understood. In this study, occurrence frequency spatial distribution convective (CBL), neutral (NBL), stable (SBL) were systematically investigated, based on intensive summertime soundings launched at 1400 Beijing time (BJT) throughout China’s radiosonde network (CRN) for period 2012 2016. Overall, occurrences CBL, NBL, SBL account 70%, 26%, 4%, respectively, suggesting that CBL dominates in summer China. terms pattern height, a prominent north–south gradient can be found higher height northwest addition, heights NBL positively (negatively) associated near-surface air temperature (humidity), whereas no apparent relationship was SBL. Furthermore, clouds tend reduce frequency, irrespective type. Roughly 70% cases occur under overcast conditions, much than those indicating govern some extent contrast, except discernible changes conditions relative clear-sky partly cloudy are more 170 m both types.

Language: Английский

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Synergistic effects of synoptic weather patterns and topography on air quality: a case of the Sichuan Basin of China

Climate Dynamics, Journal Year: 2019, Volume and Issue: 53(11), P. 6729 - 6744

Published: Sept. 9, 2019

Language: Английский

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The impact of synoptic patterns on summertime ozone pollution in the North China Plain

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 735, P. 139559 - 139559

Published: May 19, 2020

Language: Английский

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Two decades of satellite observations of AOD over mainland China using ATSR-2, AATSR and MODIS/Terra: data set evaluation and large-scale patterns

Atmospheric chemistry and physics, Journal Year: 2018, Volume and Issue: 18(3), P. 1573 - 1592

Published: Feb. 5, 2018

Abstract. The retrieval of aerosol properties from satellite observations provides their spatial distribution over a wide area in cloud-free conditions. As such, they complement ground-based measurements by providing information sparsely instrumented areas, albeit that significant differences may exist both the type obtained and temporal observations. In this paper, different types satellite-based instruments is used to provide 3-D climatology mainland China, i.e., vertical profiles extinction coefficients Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), lidar flying aboard Infrared Pathfinder Satellite Observation (CALIPSO) column-integrated (aerosol optical depth – AOD) available three radiometers: European Space Agency (ESA)'s Along-Track Scanning Radiometer version 2 (ATSR-2), Advanced (AATSR) (together referred as ATSR) NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) Terra satellite, together spanning period 1995–2015. AOD data are retrieved ATSR using dual view (ADV) v2.31 algorithm, while for MODIS Collection 6 (C6) set was merging AODs dark target (DT) deep blue (DB) algorithms, further DTDB merged product. These sets validated compared Aerosol Robotic Network (AERONET) L2.0 reference. results show that, slightly underestimates overestimates AOD. Consequently, overall lower than MODIS, difference increases increasing comparison also shows neither better other one everywhere. However, ADV has limitations bright surfaces which DB designed for. To allow C6 previous analyses where 5.1 (C5.1) were used, between C5.1 MODIS/Terra China briefly discussed. strong seasonal features vary latitude longitude across China. Two-decadal time series, averaged all presented Using 17 years basis follow evolution recent when environmental Envisat lost requires overlapping complementarity. precedes series 1995 2000 distinct increase period. two similar variations during 2011, minima maxima same years. extends beyond end 2012, showing decreasing

Language: Английский

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Linkages between aerosol pollution and planetary boundary layer structure in China

The Science of The Total Environment, Journal Year: 2018, Volume and Issue: 650, P. 288 - 296

Published: Sept. 4, 2018

Language: Английский

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