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

Abstract

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.

Characterization of PM2.5 Carbonaceous Components in a Typical Industrial City in China under Continuous Mitigation Measures

“…For Handan City, SOC concentrations were 12.86 ± 14.10 µg•m −3 , 29.29 ± 25.07 µg•m −3 , 36.76 ± 21.59 µg•m −3 , 26.03 ± 15.11 µg•m −3 and 21.32 ± 10.30 µg•m −3 from 2016 to 2020, respectively (Figure 6a). Although the SOC concentrations gradually decreased from 2018 to 2020, they were still higher than in Changchun [43], Chongqing [44], Tianjin [45] and other cities. Over the same time span, the POC concentrations (2016: 59.20 ± 28.80 µg•m −3 ; 2017: 12.44 ± 5.03 µg•m −3 ; 2018: 7.56 ± 0.92 µg•m −3 ; 2019: 7.64 ± 0.93 µg•m −3 ; 2020: 8.01 ± 0.89 µg•m −3 ) (Figure 6b) depict a different trend than the SOC concentrations.…”

“…6a). Although the SOC concentrations gradually decreased from 2018 to 2020, they were still higher than in Changchun [43], Chongqing [44], Tianjin [45] 6b) depict a different trend than the SOC concentrations. However, the ratios SOC/OC and POC/OC stayed relatively stable from 2018 to 2020 and accounted for 67.9-77.6% and 22.4-32.1%, respectively.…”

Real-Time Source Apportionment of PM2.5 Highlights the Importance of Joint Controls on Atmospheric Pollution in Cold Region of China

“…The average SO 2 concentration during MHP was ~2.0 and ~2.5 times higher than that of PHP and LHP, respectively. This might be related to the high-intensity coal-fired emissions from large power/heating plants, which were considered as crucial sources during winter in Northeast China [36]. The average ratio of PM 2.5 /PM 10 was 0.8 during PHP and MHP, but the significantly lower value of 0.55 was observed during LHP, especially 21-24 April 2019.…”

Vertical Profiles of Aerosols Induced by Dust, Smoke, and Fireworks in the Cold Region of Northeast China

“…June, July, and August are classified as summer, while September and October are considered autumn, and April and May are categorized as spring. Additionally, Changchun is located in a large, cultivated area spanning over 1.32 million hectares and is renowned for its automobile industry, optoelectronic information, and applied chemistry [28]. The city of Changchun falls within the UTC+8 time zone.…”