New open burning policy reshaped the aerosol characteristics of agricultural fire episodes in Northeast China

Abstract. Despite the growing interest in understanding haze formation in Chinese megacities, air pollution has been largely overlooked for the Harbin-Changchun (HC) metropolitan area located in the severe cold climate region in Northeast China. In this study, we unfolded significant variations of fine particulate matter (PM2.5) in HC’s central city (Harbin) during two sequential heating seasons of 2018–2019 and 2019–2020, and explored major drivers for the observed variations. The two campaigns showed comparable organic carbon (OC) levels but quite different OC sources. The biomass burning (BB) to OC contribution decreased substantially for 2019–2020, which was attributed primarily to the transition of local policies on agricultural fires, i.e., from the “legitimate burning” policy released in 2018 to the “strict prohibition” policy in 2019. Meanwhile, the contribution of secondary OC (OCsec) increased significantly, associated with the much more frequent occurrences of high relative humidity (RH) conditions during the 2019–2020 measurement period. Similar to OCsec, the major secondary inorganic ions, i.e., sulfate, nitrate and ammonium (SNA), also exhibited RH-dependent increases. Given the considerable aerosol water contents predicted for the high-RH conditions, heterogeneous reactions were likely at play in secondary aerosol formation even in the frigid atmosphere in Harbin (e.g., with daily average temperatures down to below −20 °C). In brief, compared to 2018–2019, the 2019–2020 measurement period was characterized by a policy-driven decrease of biomass burning OC, a RH-related increase of OCsec and a RH-related increase of SNA, with the former two factors generally offsetting each other. In addition, we found that open burning activities were actually not eliminated by the “strict prohibition” policy released in 2019, based on a synthesis of air quality data and fire count results. Although not evident throughout the 2019–2020 measurement period, agricultural fires broke out within a short period before crop planting in spring of 2020, and resulted in off-the-chart air pollution for Harbin, with 1- and 24-hour PM2.5 concentrations peaking at ~2350 and 900 μg/m3, respectively. This study indicates that sustainable use of crop residues remains a difficult challenge for the massive agricultural sector in Northeast China.

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Dramatic changes in Harbin aerosol during 2018–2020: the roles of open burning policy and secondary aerosol formation

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-15199-2021 ◽

2021 ◽

Vol 21 (19) ◽

pp. 15199-15211

Author(s):

Yuan Cheng ◽

Qin-qin Yu ◽

Jiu-meng Liu ◽

Xu-bing Cao ◽

Ying-jie Zhong ◽

...

Keyword(s):

Air Pollution ◽

Biomass Burning ◽

Northeast China ◽

Cold Climate ◽

Quality Data ◽

Aerosol Formation ◽

Secondary Aerosol ◽

Open Burning ◽

Measurement Period ◽

Related Increase

Abstract. Despite the growing interest in understanding haze formation in Chinese megacities, air pollution has been largely overlooked for the Harbin–Changchun (HC) metropolitan area, located in the severe cold climate region in northeast China. In this study, we unfolded significant variations of fine particulate matter (PM2.5) in HC's central city (Harbin) during two sequential heating seasons of 2018–2019 and 2019–2020, and we explored major drivers for the observed variations. The two campaigns showed comparable organic carbon (OC) levels but quite different OC sources. The biomass burning (BB) to OC contribution decreased substantially for 2019–2020, which was attributed primarily to the transition of local policies on agricultural fires, i.e., from the “legitimate burning” policy released in 2018 to the “strict prohibition” policy in 2019. Meanwhile, the contribution of secondary OC (OCsec) increased significantly, associated with the much more frequent occurrences of high relative humidity (RH) conditions during the 2019–2020 measurement period. Similar to OCsec, the major secondary inorganic ions, i.e., sulfate, nitrate and ammonium (SNA), also exhibited RH-dependent increases. Given the considerable aerosol water contents predicted for the high-RH conditions, heterogeneous reactions were likely at play in secondary aerosol formation even in the frigid atmosphere in Harbin (e.g., with daily average temperatures down to below −20 ∘C). In brief, compared to 2018–2019, the 2019–2020 measurement period was characterized by a policy-driven decrease of biomass burning OC, a RH-related increase of OCsec and a RH-related increase of SNA, with the first two factors generally offsetting each other. In addition, we found that open burning activities were actually not eliminated by the strict prohibition policy released in 2019, based on a synthesis of air quality data and fire count results. Although not occurring during the 2019–2020 measurement period, agricultural fires broke out within a short period before crop planting in spring of 2020, and this resulted in off-the-charts air pollution for Harbin, with 1 h and 24 h PM2.5 concentrations peaking at ∼ 2350 and 900 µg/m3, respectively. This study indicates that sustainable use of crop residues remains a difficult challenge for the massive agricultural sector in northeast China.

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Women's Agency in Controlling Reproduction in Rural Northeast China

PsycEXTRA Dataset ◽

10.1037/e645692011-001 ◽

2010 ◽

Author(s):

Lihong Shi

Keyword(s):

Northeast China ◽

Women's Agency ◽

Women’S Agency

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Review for "Petrology, geochemistry, and zircon U-Pb isotopes of Xintian Complex in Yanbian area, Northeast China: Evidence for magma mixing and geodynamics processes"

10.1002/gj.3749/v1/review1 ◽

2019 ◽

Keyword(s):

Northeast China ◽

Magma Mixing ◽

Pb Isotopes

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Assessment of viral assemblages in different types of wetland water in northeast China using RAPD-PCR

Aquatic Microbial Ecology ◽

10.3354/ame01952 ◽

2020 ◽

Vol 85 ◽

pp. 183-196

Author(s):

Y Sun ◽

J Liu ◽

Q Yao ◽

J Jin ◽

X Liu ◽

...

Keyword(s):

Bacterial Community ◽

Water Samples ◽

Northeast China ◽

Bacterial Community Composition ◽

Freshwater Wetlands ◽

Viral Community ◽

Rapd Pcr ◽

Wetland Water ◽

Different Types ◽

Viral Communities

Viruses are the most abundant and ubiquitous biological entities in various ecosystems, yet few investigations of viral communities in wetlands have been performed. To address this data gap, water samples from 6 wetlands were randomly collected across northeast China; viruses in the water were concentrated by sequential tangential flow filtration, and viral communities were assessed through randomly amplified polymorphic DNA-PCR (RAPD-PCR) with 4 decamer oligonucleotide primers. Principal coordinate analysis and hierarchical clustering analysis of the DNA fingerprints showed that viral community compositions differed among the water samples: communities in the 2 coastal wetlands were more similar to each other than to those in the 4 freshwater wetlands. The Shannon-Weaver index (H) and evenness index (E) of the RAPD-PCR fingerprint also differed among the 6 wetlands. Mantel test revealed that the changes in viral communities in wetland water were most closely related to the water NH4+-N and inorganic C content, followed by total K, P, C and NO3--N. DNA sequence analysis of the excised bands revealed that viruses accounted for ~40% of all sequences. Among the hit viral homologs, the majority belonged to the Microviridae. Moreover, variance partitioning analysis showed that the viral community contributed 24.58% while environmental factors explained 30.56% of the bacterial community variation, indicating that the bacterial community composition was strongly affected by both viral community and water variables. This work provides an initial outline of the viral communities from different types of wetlands in northeast China and improves our understanding of the viral diversity in these ecosystems.

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