Query: Chemical characterization of PM2.5 during spring festival

title: Chemical characterization, the transport pathways and potential sources of PM2.5 in Shanghai: Seasonal variations
abstract: The 24 h PM2.5 samples were collected at the site of East China University of Science and Technology (ECUST) in Shanghai from 2011 to 2012, representing winter, spring, summer and autumn, respectively. And PM2.5 and its chemical components including organic carbon (OC) elemental carbon (EC) water soluble organic carbon (WSOC) humic like substance carbon (HULIS C) and water soluble ions were analyzed. The results suggested that the average PM2.5 concentrations were (70.35 43.75) mg/m3, (69.76 38.67) mg/m3, (51.26 28.25) mg/m3 and (82.37 48.70) mg/m3 in winter, spring, summer and autumn, respectively. Secondary inorganic ions (sulfate, nitrate and ammonium) were the dominant pollutants of PM2.5 in the four seasons. Total carbon (TC) was an important component explaining above 15% of PM2.5. OC/EC ratios were all above 2 ranging from 4.31 to 6.35; particularly in winter it reached the highest 6.35 which demonstrated that secondary organic carbon (SOC) should be a significant composition of PM2.5. The SOC calculated based on the OC/EC ratio method had stronger correlation with WSOC in summer and autumn (summer: R2 0.73 and autumn: R2 0.75) The HULIS C and SOC most significantly correlated in autumn (R2 0.83) The data showed that PM2.5 atmospheric aerosols were more acidic in autumn and the concentrations of PM2.5 and its chemical components were much higher. Factor analysis (FA) cluster analysis of air mass back trajectories, potential source contribution function (PSCF) model and concentration weighted trajectory (CWT) model were used to investigate the transport pathways and identify potential source areas of PM2.5 in different seasons. FA identified various sources of PM2.5: secondary aerosol reactions, the aged sea salts and road dusts. The results of cluster analysis, PSCF model and CWT model demonstrated that the local sources in the Yangtze River Delta Region (YRDR) made significant contributions to PM2.5. During winter and autumn long time transport from the Circum Bohai Sea Region (CBSR) and northwestern China including the Inner Mongol had adverse effects.

title: Chemical Characterization and Source Apportionment of PM 2 5 during Spring and Winter in the Yangtze River Delta China
abstract: To investigate the characteristics and sources of PM2.5 in the Yangtze River Delta (YRD) region, a total of 10 sampling sites were selected in the three major cities of Shanghai, Nanjing, and Ningbo and the regional background city of Lin'an, and 380 samples were collected in spring and winter. The spatiotemporal characteristics of the PM2.5 mass concentration and the chemical components were analyzed. Meanwhile, air mass clusters and the positive matrix factorization (PMF) source apportion model were comprehensively used to identify the sources of PM2.5. The mass concentration of PM2.5 in winter (83.51 107.64 mg m) was higher than that in spring (54.11 85.72 mg m) Sulfate, nitrate, and ammonium (SNA) dominated the PM2.5, accounting for 39.0% in spring and 46.1% in winter in the YRD region. Higher ratio of secondary organic carbon (SOC) to organic carbon (OC) generally occurred in winter due to increased emissions of organic precursors. The mean equivalent ratio of AE/CE was 0.81 0.25 in winter and 0.96 0.33 in spring, which indicated a slight alkalinity of the atmospheric particles in the YRD region. Secondary aerosols (29.44% and traffic (25.66% were identified as the main sources of PM2.5 in the YRD during spring, and they contributed 22.71% and 29.71% in winter. In addition, air mass flow from Northern China imported substantial fugitive soils to the YRD region in spring and enhanced the contribution of combustion in winter through long range transport, while air masses originating from Southwestern China were strongly associated with biomass burning. Our results showed that the PM2.5 concentration and chemical characterization in the YRD region was significantly influenced by air mass transport.

title: Chemical Characteristics of PM2.5 and Water Soluble Organic Nitrogen in Yangzhou, China
abstract: Chemical characterization of fine atmospheric particles (PM2.5) is important for effective reduction of air pollution. This work analyzed PM2.5 samples collected in Yangzhou, China, during 2016. Ionic species, organic matter (OM) elemental carbon (EC) and trace metals were determined, and an Aerodyne soot particle aerosol mass spectrometer (SP AMS) was introduced to determine the OM mass, rather than only organic carbon mass. We found that inorganic ionic species was dominant ~52% organics occupied about 1/4, while trace metals ~1% and EC ~2.1% contributed insignificantly to the total PM2.5 mass. Water soluble OM appeared to link closely with secondary OM, while water insoluble OM correlated well with primary OM. The PM2.5 concentrations were relatively low during summertime, while its compositions varied little among different months. Seasonal variations of water soluble organic nitrogen (WSON) concentrations were not significant, while the mass contributions of WSON to total nitrogen were remarkably high during summer and autumn. WSON was found to associate better with secondary sources based on both correlation analyses and principle component analyses. Analyses of potential source contributions to WSON showed that regional emissions were dominant during autumn and winter, while the ocean became relatively important during spring and summer.

title: Characterization and source apportionment of PM2.5 based on error estimation from EPA PMF 5.0 model at a medium city in China.
abstract: Heze city, a medium size city in Shandong province, Eastern China. Ambient PM2.5 samples were collected in urban area of Heze from August 2015 to April 2016, and chemical species and sources of PM2.5 were investigated in this paper. The results indicated that the average concentration of PM2.5 was 100.9 mg/m3 during the sampling period, and the water soluble ions, carbonaceous species included elemental carbon (EC) and organic carbon (OC) as well as elements contributed 32.7 51.7% 16.3% and 12.5% respectively, to PM2.5. Pearson's correlation analysis showed that the existing form of NH4+ was more complex and diverse in spring/summer, and ammonium nitrate, ammonium sulfate and ammonium hydrogen sulfate might be major form of NH4+ in autumn/winter. Correlation analysis between PM2.5 and SO42 /NO3 PM2.5 and OC/EC during different seasons suggested that mobile sources might make an important impact on the increase of PM2.5 concentrations in spring/summer, and stationary sources might play a critical role on the increase of PM2.5 concentrations in autumn/winter. Seven factors were selected in Positive Matrix Factorization (PMF) models analysis based on the Error Estimation (EE) diagnostics during different seasons. Secondary source had the highest contribution to PM2.5 in Heze for the whole year, and followed by coal combustion, vehicle exhaust, soil dust, construction dust, biomass burning and metal manufacturing, and their annual contributions to PM2.5 were 26.5% 17.2% 16.5% 11.5% 7.7% 7.0% and 3.8% respectively. The air masses that were originated from Mongolia reflected the features of large scale and long distance air transport; while the air masses that began in Jiangsu, Shandong and Henan showed the features of small scale and short distance. Shandong, Henan and Jiangsu were identified as the major potential sources areas of PM2.5 by using potential source contribution function (PSCF) and concentration weighted trajectory (CWT) models.

title: The effects of firework regulation on air quality and public health during the Chinese Spring Festival from 2013 to 2017 in a Chinese megacity.
abstract: Fireworks displays are a traditional form of celebration during the Chinese Spring Festival (Festival) In response to the heavy air pollution caused by fireworks, Shanghai, a megacity in China, has imposed regulatory measures on the use of fireworks in recent years. To investigate air quality trends before and after firework regulation was established and quantify its efficiency, gaseous pollutants, PM2.5 levels, and PM2.5 chemical composition were synchronously measured at 1 h time intervals at an urban site and a suburban site in Shanghai in the period during and around the Festival from 2013 to 2017. PM2.5 concentrations at the urban site during the Festival over the five year period were 79 (max: 524) 94 (290) 53 (163) 50 (146) and 32 (156) mg/m3, respectively, presenting a decreasing trend at a rate of 13.8 mg/m3/yr (p 0.05) K+ concentrations, which serve as a tracer of fireworks, were 8.2 (max: 159.4) 2.5 (14.6) 2.2 (10.4) 4.3 (44.2) and 0.8 (4.5) mg/m3 during the Festival from 2013 to 2017, respectively, and thus decreased at a rate of 1.3 mg/m3/yr (p 0.17) Accordingly, fireworks contributed 41 (51.9% 38 (36.5% 6 (10.3% 21 (35.6% and 4 mg/m3 (12.1% to PM2.5, respectively, implying the effectiveness of firework regulation in Shanghai. Health effects attributed to PM2.5 pollution in Shanghai during the Festival were assessed based on Poisson regression. The number of premature deaths related to short term PM2.5 exposure in Shanghai during the Festival from 2013 to 2017 was 75 (95% CI: 27, 108) 92 (30, 129) 55 (18, 76) 49 (19, 70) and 31 (12, 45) respectively. Daily mortality due to PM2.5 exposure during the Festival from 2013 to 2017 accounted for 1.4 3.8% of total daily mortality in Shanghai. This study provides scientific evidence of air quality improvement and the effectiveness of firework regulation in

title: Chemical characteristics of haze particles in Xi'an during Chinese Spring Festival: Impact of fireworks burning.
abstract: Fireworks burning releases massive fine particles and gaseous pollutants, significantly deteriorating air quality during Chinese Lunar New Year (LNY) period. To investigate the impact of the fireworks burning on the atmospheric aerosol chemistry, 1 hr time resolution of PM2.5 samples in Xi'an during the winter of 2016 including the LNY were collected and detected for inorganic ions, acidity and liquid water content (LWC) of the fine aerosols. PM2.5 during the LNY was 167+ 87mg/m3, two times higher than the China National Ambient Air Quality Standard (75mg/m3) K+ (28wt. of the total ion mass) was the most abundant ion in the LNY period, followed by SO42 (25wt. and Cl (18wt. In contrast, NO3 (34wt. was the most abundant species in the haze periods (hourly PM2.5>75mg/m3) followed by SO42 (29.2wt. and NH4+ (16.3wt. while SO42 (35wt. was the most abundant species in the clean periods (hourly PM2.5<75mg/m3) followed by NO3 (23.1wt. and NH4+ (11wt. Being different from the acidic nature in the non LNY periods, aerosol in the LNY period presented an alkaline nature with a pH value of 7.8+ 1.3. LWC during the LNY period showed a robust linear correlation with K2SO4 and KCl, suggesting that aerosol hygroscopicity was dominated by inorganic salts derived from fireworks burning. Analysis of correlations between the ratios of NO3 /SO42 and NH4+/SO42 indicated that heterogeneous reaction of HNO3 with NH3 was an important formation pathway of particulate nitrate and ammonium during the LNY period.

title: The impact of fireworks control on air quality in four Northern Chinese cities during the Spring Festival
abstract: Online measurements for chemical components in PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 mm) were carried out in Qinhuangdao (QHD) Tangshan (TS) Shijiazhuang (SJZ) and Zhengzhou (ZZ) China, from December 14, 2016 to February 2, 2017 to assess the impact of the fireworks control on air quality during the Spring Festival. Pre fireworks, fireworks, and post fireworks periods were all assessed. Results show that average concentrations of PM2.5 during fireworks periods were in the following order of SJZ ZZ TS QHD. Fireworks displays have great impacts on concentrations of K+ SO42 Cl Mg2+ and OC. According to results of PM2.5 source apportionment, fireworks were the largest PM2.5 source during fireworks periods in QHD, TS, SJZ, and ZZ, accounting for 68.9% 53.8% 61.1% and 51.0% of PM2.5, respectively. This result was similar to the result of the relative ratio method (68.6% in QHD, 57.2% in TS, 63.0% in SJZ, 53.9% in ZZ) Based on results of PM2.5 source apportionment, the contribution of fireworks from 19:00 on January 27 to 8:00 on January 28 to PM2.5 in ZZ (44.1% was the lowest in comparison with QHD (75.7% TS (66.0% and SJZ (63.8% which can be ascribed to stringent fireworks control measures in ZZ. Although fireworks displays were banned in QHD and SJZ during the Spring Festival, contributions of fireworks to PM2.5 in these two cities were higher or slightly lower than that of TS during the special period when fireworks were allowed to be set off in TS, indicating that no stringent measures were taken to effectively control fireworks displays in QHD and SJZ. These results highlight the necessity of limiting fireworks emissions during the Spring Festival.

title: [Influence of Burning Fireworks on the Atmosphere During the Spring Festival in Guangzhou in 2020]
abstract: Twenty one air quality monitoring stations including four with single particle aerosol mass spectrometers (SPAMS) were used to observe air quality and aerosol particulates during the 2020 Spring Festival (from January 21 to 28) in Guangzhou. The effect of burning fireworks on the atmosphere of Guangzhou and its eleven administrative regions was examined, and the chemical composition of firework particles was detected and analyzed by single particle aerosol mass spectrometry. The results show that the burning of fireworks had a significant impact on air quality in the discharge area and the prohibited discharge area. The concentrations of PM2.5, PM10, and SO2 sharply increased in Guangzhou on New Year's Eve. Air quality in Zengcheng District, Baiyun District, Huangpu District, and some areas of Tianhe District was also affected by the concentrated burning of fireworks on January 25 between 01:00 and 06:00. A method of fireworks tracing based on SPAMS using Al+ as a tracer was established with a time resolution of 5 min. The main particle types emitted by the burning fireworks were levoglucan, potassium rich, and mineral. These particles were well mixed with nitrate, but this was not conducive to the formation of ammonium.

title: Characterization of summer PM2.5 aerosols from four forest areas in Sichuan, SW China
abstract: Aerosol samples were collected over 24 and 12 h to represent day/night aerosol characteristics in forest areas at Ya'an Baima Spring Scenic Area (BM) Panzhihua Cycas National Nature Reserve (PZ) Gongga Mountain National Nature Reserve (GG) and Wolong National Nature Reserve (WL) during the summers of 2010 2012. Mass and chemical component concentrations, including organic carbon, elemental carbon, and inorganic ions (F Cl NO2 NO3 SO42 C2O42 PO43 K+ Na+ Ca2+ Mg2+ and NH4+ of PM2.5 aerosols were measured. The average PM2.5 concentrations for 24 h were 72.42, 104.89, 20.55, and 29.19 mg/m3 at BM, PZ, GG, and WL, respectively. Organic matter accounted for 38.0 49.3% while elemental carbon accounted for 2.0 5.7% of PM2.5 mass. The sum concentrations of SO42 NH4+ and NO3 accounted for 23.0% 17.4% 22.1% and 30.5% of PM2.5 mass at BM, PZ, GG, and WL, respectively. Soil dust was also an important source of PM2.5, accounting for 6.3% 17.0% 10.4% and 19.1% of PM2.5 mass at BM, PZ, GG, and WL, respectively. These reconstructed masses accounted for 75.9 102.0% of PM2.5 mass from the four forest areas of SW China.

title: Chemical characterization of the long range transport of firework/firecracker emissions over the Korean Peninsula: A novel indicator of Asian continental outflows
abstract: The long range transport (LRT) of pollutants between countries in Northeast Asia is a serious issue. However, reliable quantification of LRT pollutants has not been performed due to a lack of clear evidence of the transport between countries. Hourly chemical composition of PM2.5 (particulate matter with a diameter of =2.5 mm) was measured continuously at a suburban site in Daejeon, Korea during the Lunar New Year festival period to investigate the influence of firework/firecracker emissions from China over areas downwind subject to LRT. Elevated PM10 (particulate matter with a diameter of =10 mm) and PM2.5 mass concentrations were observed over the Korean Peninsula during the third day of the Lunar New Year festival (30 January 2017) when air masses originated from the northern part of China. Water soluble potassium (K+ an indicator of both firework/firecracker and biomass burning, increased significantly during the third day of the Lunar New Year festival with an episode to non episode ratio of 7.5, whereas no increase in levoglucosan, an indicator of biomass burning, was observed. Because firework/firecracker activities do not typically occur over the Korean Peninsula during the Lunar New Year festival, elevated K+ indicates that haze plumes mixed with firework/firecracker emissions in China impacted the Korean Peninsula through the LRT. This study finds, for the first time, clear evidence of the LRT of pollutants between source and receptor countries in Northeast Asia under Asian continental outflow.