Assessment of Carbonaceous Aerosols at Mount Tai, North China: Secondary Formation and Regional Source Analysis

Abstract. We simulate elemental carbon (EC) and organic carbon (OC) aerosols in China and compare model results to surface measurements at Chinese rural and background sites, with the goal of deriving "top-down" emission estimates of EC and OC, as well as better quantifying the secondary sources of OC. We include in the model state-of-the-science Chinese "bottom-up" emission inventories for EC (1.92 Tg C yr−1) and OC (3.95 Tg C yr−1), as well as updated secondary OC formation pathways. The average simulated annual mean EC concentration at rural and background site is 1.1 μg C m−3, 56% lower than the observed 2.5 μg C m−3. The average simulated annual mean OC concentration at rural and background sites is 3.4 μg C m−3, 76% lower than the observed 14 μg C m−3. Multiple regression to fit surface monthly mean EC observations at rural and background sites yields best estimate of Chinese EC source of 3.05 ± 0.78 Tg C yr−1. Based on the top-down EC emission estimate and observed seasonal primary OC/EC ratios, we estimate Chinese OC total emissions to be 6.67 ± 1.30 Tg C yr−1. Using these top-down estimates, the simulated average annual mean EC concentration at rural and background sites significantly improved to 1.9 μg C m−3. However, the model still significantly underestimates observed OC in all seasons (simulated average annual mean OC at rural and background sites is 5.4 μg C m−3), with little skill in capturing the spatiotemporal variability. Secondary formation accounts for 21% of Chinese annual mean surface OC in the model, with isoprene being the most important precursor. In summer, as high as 62% of the observed surface OC may be due to secondary formation in eastern China. Our analysis points to three shortcomings in the current bottom-up inventories of Chinese carbonaceous aerosols: (1) the anthropogenic source is severely underestimated, particularly for OC; (2) there is a missing source in western China, likely associated with the use of biofuels or other low-quality fuels for heating; and (3) sources in fall are not well represented, either because the seasonal shifting of emissions and/or secondary formation are poorly captured or because specific fall emission events are missing. More regional measurements with better spatiotemporal coverage are needed to resolve these shortcomings.

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Secondary Formation of Aerosols Under Typical High‐Humidity Conditions in Wintertime Sichuan Basin, China: A Contrast to the North China Plain

Journal of Geophysical Research Atmospheres ◽

10.1029/2021jd034560 ◽

2021 ◽

Vol 126 (10) ◽

Author(s):

Yujue Wang ◽

Min Hu ◽

Wei Hu ◽

Jing Zheng ◽

Hongya Niu ◽

...

Keyword(s):

Sichuan Basin ◽

North China Plain ◽

North China ◽

High Humidity ◽

The North ◽

The North China Plain ◽

Secondary Formation

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Primary emissions versus secondary formation of fine particulate matter in the most polluted city (Shijiazhuang) in North China

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-2283-2019 ◽

2019 ◽

Vol 19 (4) ◽

pp. 2283-2298 ◽

Cited By ~ 20

Author(s):

Ru-Jin Huang ◽

Yichen Wang ◽

Junji Cao ◽

Chunshui Lin ◽

Jing Duan ◽

...

Keyword(s):

Particulate Matter ◽

North China ◽

Fine Particulate Matter ◽

Mass Range ◽

Organic Aerosol ◽

Average Mass ◽

Episodic Events ◽

Secondary Formation ◽

Primary Emissions ◽

Pollution Events

Abstract. Particulate matter (PM) pollution is a severe environmental problem in the Beijing–Tianjin–Hebei (BTH) region in North China. PM studies have been conducted extensively in Beijing, but the chemical composition, sources, and atmospheric processes of PM are still relatively less known in nearby Tianjin and Hebei. In this study, fine PM in urban Shijiazhuang (the capital of Hebei Province) was characterized using an Aerodyne quadrupole aerosol chemical speciation monitor (Q-ACSM) from 11 January to 18 February in 2014. The average mass concentration of non-refractory submicron PM (diameter <1 µm, NR-PM1) was 178±101 µg m−3, and it was composed of 50 % organic aerosol (OA), 21 % sulfate, 12 % nitrate, 11 % ammonium, and 6 % chloride. Using the multilinear engine (ME-2) receptor model, five OA sources were identified and quantified, including hydrocarbon-like OA from vehicle emissions (HOA, 13 %), cooking OA (COA, 16 %), biomass burning OA (BBOA, 17 %), coal combustion OA (CCOA, 27 %), and oxygenated OA (OOA, 27 %). We found that secondary formation contributed substantially to PM in episodic events, whereas primary emissions were dominant (most significant) on average. The episodic events with the highest NR-PM1 mass range of 300–360 µg m−3 were comprised of 55 % of secondary species. On the contrary, a campaign-average low OOA fraction (27 %) in OA indicated the importance of primary emissions, and a low sulfur oxidation degree (FSO4) of 0.18 even at RH >90 % hinted at insufficient oxidation. These results suggested that in Shijiazhuang in wintertime fine PM was mostly from primary emissions without sufficient atmospheric aging, indicating opportunities for air quality improvement by mitigating direct emissions. In addition, secondary inorganic and organic (OOA) species dominated in pollution events with high-RH conditions, most likely due to enhanced aqueous-phase chemistry, whereas primary organic aerosol (POA) dominated in pollution events with low-RH and stagnant conditions. These results also highlighted the importance of meteorological conditions for PM pollution in this highly polluted city in North China.

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Temporal Variation and Source Analysis of Carbonaceous Aerosol in Industrial Cities of Northeast China during the Spring Festival: The Case of Changchun

Atmosphere ◽

10.3390/atmos11090991 ◽

2020 ◽

Vol 11 (9) ◽

pp. 991

Author(s):

Mengduo Zhang ◽

Shichun Zhang ◽

Qiuyang Bao ◽

Chengjiang Yang ◽

Yang Qin ◽

...

Keyword(s):

Wind Speed ◽

Temporal Variation ◽

Northeast China ◽

Carbonaceous Aerosol ◽

Source Analysis ◽

Formation Mechanisms ◽

Carbonaceous Aerosols ◽

Industrial Cities ◽

Spring Festival ◽

Major Period

Carbonaceous aerosol, one of the major components of atmospheric aerosols, significantly affects haze episodes, climate change, and human health. Northeastern China suffers severe air pollution, especially in some periods (e.g., the Spring Festival). However, studies on carbonaceous aerosols in typical northeast industrial cities (i.e., Changchun) are rare, limiting further comprehension of the atmospheric haze formation. In this study, we monitored the concentrations of carbonaceous aerosols (i.e., OC and EC) in Changchun during the Lunar New Year of 2018 (i.e., from Lunar 20 December to Lunar 20 January), and analyzed the temporal variation and source contributions via the HYbrid-Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model with the potential source contribution factor weights (PSCF) method. The daily concentrations of OC and EC were 9.00 ± 2.81 and 1.57 ± 0.46 µg m−3, respectively, and were significantly lower at nighttime than at the day during the Spring Festival. The concentrations during the major period (i.e., OC: 8.13 ± 2.93 µg m−3; EC: 1.47 ± 0.47 µg m−3 in festival days), including the Lunar Little New Year; the Lunar New Year’s Eve; New Year’s Day; Lunar 5 January, and the Spring Lantern Festival, were mainly from the northwestward with the wind speed of 4–6 m/s being lower than that of normal period (OC: 9.87 ± 2.46 µg m−3; EC: 1.67 ± 0.44 µg m−3) from the southeastward with a wind speed of 6–7 m/s. The direction of the airflow trajectory was mainly in local, northwestward, and northward, carrying particulate matter and gaseous pollutants. In major period, the daily concentration of atmospheric pollutants presented a bimodal trend, with peaks appearing regularly from 11:00 a.m. to 12:00 p.m. and 5:00 p.m. 10:00 p.m., which might be related to traffic, cooking, and firecrackers. The OC/EC was greater than 2 during the whole period, indicating the generation of secondary organic aerosols (i.e., SOC). This study was essential to understand the formation mechanisms of severe pollution episodes and develop control measures for the industrial cities of Northeast China during the Spring Festival.

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