scholarly journals Temporal and Spatial Variation of PM2.5 in Xining, Northeast of the Qinghai–Xizang (Tibet) Plateau

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 953 ◽  
Author(s):  
Xiaofeng Hu ◽  
Yongzheng Yin ◽  
Lian Duan ◽  
Hong Wang ◽  
Weijun Song ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Spatial Variation ◽  
Average Concentration ◽  
Water Soluble ◽  
Salt Lakes ◽  
Urban Site ◽  
Annual Average ◽  
Annual Average Concentration ◽  
Oxidation Ratio ◽  
Pm2.5 Concentration

PM2.5 was sampled from January 2017 to May 2018 at an urban, suburban, industrial, and rural sites in Xining. The annual mean of PM2.5 was highest at the urban site and lowest at the rural site, with an average of 51.5 ± 48.9 and 26.4 ± 17.8 μg·m−3, respectively. The average PM2.5 concentration of the industrial and suburban sites was 42.8 ± 27.4 and 37.2 ± 23.7 μg·m−3, respectively. All sites except for the rural had concentrations above the ambient air quality standards of China (GB3095-2012). The highest concentration of PM2.5 at all sites was observed in winter, followed by spring, autumn, and summer. The concentration of major constituents showed statistically significant seasonal and spatial variation. The highest concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and water-soluble inorganic ions (WSIIs) were found at the urban site in winter. The average concentration of F− was higher than that in many studies, especially at the industrial site where the annual average concentration of F− was 1.5 ± 1.7 μg·m−3. The range of sulfur oxidation ratio (SOR) was 0.1–0.18 and nitrogen oxidation ratio (NOR) was 0.02–0.1 in Xining. The higher SO42−/NO3− indicates that coal combustion has greater impact than vehicle emissions. The results of the potential source contribution function (PSCF) suggest that air mass from middle- and large-scale transport from the western areas of Xining have contributed to the higher level of PM2.5. On the basis of the positive matrix factorization (PMF) model, it was found that aerosols from salt lakes and dust were the main sources of PM2.5 in Xining, accounting for 26.3% of aerosol total mass. During the sandstorms, the concentration of PM2.5 increased sharply, and the concentrations of Na+, Ca2+ and Mg2+ were 1.13–2.70, 1.68–4.41, and 1.15–5.12 times higher, respectively, than annual average concentration, implying that aerosols were mainly from dust and the largest saltwater lake, Qinghai Lake, and many other salt lakes in the province of Qinghai. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was utilized to study the surface components of PM2.5 and F− was found to be increasingly distributed from the surface to inside the particles. We determined that the extremely high PM2.5 concentration appears to be due to an episode of heavy pollution resulting from the combination of sandstorms and the burning of fireworks.

scholarly journals Secondary Organic Aerosols in PM2.5 in Bengbu, a Typical City in Central China: Concentration, Seasonal Variation and Sources

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 854
Author(s):  
Shiwei Zhang ◽  
Hao Tang ◽  
Qing Li ◽  
Liang Li ◽  
Chaojun Ge ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Organic Carbon ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Average Concentration ◽  
Water Soluble ◽  
Central China ◽  
Urban Site ◽  
Formation Mechanisms ◽  
Pollution Levels

To investigate the concentration, seasonal variation, and sources of secondary organic aerosols (SOAs) in the inland areas of central China, 244 seasonal PM2.5 samples were collected from January to October 2019 at one urban site and one suburban site simultaneously in Bengbu of Anhui Province. Concentrations of organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and typical organic tracers, including saccharides, tracers of SOAs from isoprene, terpenes, and toluene, were measured. Results showed that Bengbu has high pollution levels of organic aerosols, with annual average OC concentrations of about 9.5 μg m−3. About 60% of the OC in PM2.5 in Bengbu was water soluble. Different seasonal trends were found for the SOA tracers of isoprene, monoterpene, seisquiterpene, and toluene. The highest seasonal average concentration of the isoprene SOA tracers was observed in summer and of the monoterpene and seisquiterpene SOA tracers in autumn. A stronger correlation was found between the 2-methylglyceric acid-to-2-methyltetrol ratio (MGA/MTL) and ambient temperature than that between MGA/MTLs and NOX concentration, suggesting that temperature has an important impact on the MGA/MTL ratio besides NOX concentration. The OC/EC-based method, WSOC-based method, tracer yield method, and positive matrix factorization (PMF)-based method were used to estimate the concentration and sources of secondary organic carbon (SOC), and the PMF-based method was believed to be able to give reasonable results. SOC was the main contributor of WSOC in PM2.5 in Bengbu, while biomass burning made an important contribution to WSOC in autumn and winter (~40%). SOC was mainly associated with SOA tracers in summer and mainly associated with secondary ions in spring and winter, suggesting different formation mechanisms in different seasons.

scholarly journals Heavy Metal Content in Water of Resko Lake (North-West Poland)

2013 ◽  
Vol 13 ◽  
pp. 279-287 ◽  
Author(s):  
Piotr Daniszewski ◽  
Ryszard Konieczny
Keyword(s):  
Surface Water ◽  
Water Samples ◽  
Metal Content ◽  
Research Work ◽  
Average Concentration ◽  
Permissible Limit ◽  
Toxic Heavy Metals ◽  
Annual Average ◽  
North West ◽  
Annual Average Concentration

The present research work deals with the quantification of toxic heavy metals in the water samples collected from Lake of Resko (North-West Poland). While the annual average concentration of Cadmium was calculated as 0.34 ppm in 2008 of the year and 0.28 ppm in 2009 of the year. The values obtained were found to be below the permissible limit of 2.0 ppm set for inland surface water. While the annual average concentration of Chromium was calculated as 1,75 ppm in 2008 of the year and 1.97 ppm in 2009 of the year. Which was very much above the permissible limit of 0.1 ppm set for inland surface water. The observed annual average concentration of Copper in the water was 0.05 ppm in 2008 of the year and 0.06 ppm in 2009 of the year, which was below the permissible limit of 3.0 ppm set for inland surface water. While the annual average concentration of Mercury was calculated as 0.03 ppm in 2008 of the year and 0.04 ppm in 2009 of the year, which was very much above the maximum limit of 0.01 ppm set for inland surface water. The annual average concentration of Nickel in the water samples was observed to be 2.07 ppm in 2008 of the year and 2.09 ppm in 2009 of the year, which is close to the limit of 3.0 ppm set for inland surface water. The annual average concentration of Pb in the water samples was observed to be 0.07 ppm in 2008 of the year and 0.05 ppm in 2009 of the year, which is above the permissible limit of 0.1 ppm set for inland surface water. The results of the present investigation indicate that the annual average concentration of Zn in water samples was 3.02 ppm in 2008 of the year and 2.74 ppm in 2009 of the year, which is above the permissible limit of 5.0 ppm set for inland surface water.

Evaluation and Management of Ambient Air Quality, with Special Reference to China

1980 ◽  
Vol 7 (3) ◽  
pp. 223-228 ◽  
Author(s):  
Yao Zhi-Qi
Keyword(s):  
Air Quality ◽  
Geometric Mean ◽  
Monitoring And Evaluation ◽  
Ambient Air ◽  
Average Concentration ◽  
Quality Indices ◽  
Ambient Air Quality ◽  
Annual Average ◽  
Hygienic Standard ◽  
Annual Average Concentration

Monitoring and evaluation of air quality in urban and industrial areas are essential for air quality management. For evaluating the composite air-quality in the concomitant presence of several pollutants in the atmosphere, many air quality indices have been developed. This paper presents two indices, the ‘composite air-quality index (I1)’ and ‘the standard-exceeding index of air pollution (I2)’ together with their respective sub-indices, for the pollutants monitored and for use in combination.The first index, I1, is based on the annual average concentration measured in a year for each pollutant; it measures the overall composite air-quality. By relating the annual average concentration (Ci) of each pollutant to its hygienic standard (Si), as many (Ci/Si) values as the number of pollutant parameters monitored are found, whereupon I1 is computed as the geometric mean of the maximum and average of all (Ci/Si) values. A greater value of I1 means worse composite air-quality. It is simpler to compute than those more sophisticated ones in the literature, and holds the unique characteristic of considering, and yet not overemphasizing as formula (3) does (Nemerow, 1974), the maximum (Ci/Si) value.

scholarly journals Chemical Characteristics of Major Inorganic Ions in PM2.5 Based on Year-Long Observations in Guiyang, Southwest China—Implications for Formation Pathways and the Influences of Regional Transport

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 847
Author(s):  
Hao Xiao ◽  
Hua-Yun Xiao ◽  
Zhong-Yi Zhang ◽  
Neng-Jian Zheng ◽  
Qin-kai Li ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Inorganic Ions ◽  
Sulfur Oxidation ◽  
Average Concentration ◽  
Water Soluble ◽  
Soluble Ions ◽  
Water Soluble Ions ◽  
Transformation Mechanisms ◽  
Higher Temperature ◽  
Oxidation Ratio

Sulfate, nitrate and ammonium (SNA) are the dominant components of water-soluble ions (WSIs) in PM2.5, which are of great significance for understanding the sources and transformation mechanisms of PM2.5. In this study, daily PM2.5 samples were collected from September 2017 to August 2018 within the Guiyang urban area and the concentrations of the major WSIs in the PM2.5 samples were characterized. The results showed that the average concentration of SNA (SO42−, NO3−, NH4+) was 15.01 ± 9.35 μg m−3, accounting for 81.05% (48.71–93.76%) of the total WSIs and 45.33% (14.25–82.43%) of the PM2.5 and their possible chemical composition in PM2.5 was (NH4)2SO4 and NH4NO3. The highest SOR (sulfur oxidation ratio) was found in summer, which was mainly due to the higher temperature and O3 concentrations, while the lowest NOR (nitrogen oxidation ratio) found in summer may ascribe to the volatilization of nitrates being accelerated at higher temperature. Furthermore, the nitrate formation was more obvious in NH4+-rich environments so reducing NH3 emissions could effectively control the formation of nitrate. The results of the trajectory cluster analysis suggested that air pollutants can be easily enriched over short air mass trajectories from local emission sources, affecting the chemical composition of PM2.5.

scholarly journals Analysis of the distributions of hourly NO<sub>2</sub> concentrations contributing to annual average NO<sub>2</sub> concentrations across the European monitoring network between 2000 and 2014

2017 ◽  
Author(s):  
Christopher S. Malley ◽  
Erika von Schneidemesser ◽  
Sarah Moller ◽  
Christine F. Braban ◽  
W. Kevin Hicks ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Monitoring Network ◽  
Average Concentration ◽  
Monitoring Site ◽  
The European Union ◽  
Annual Average ◽  
Limit Value ◽  
Annual Average Concentration ◽  
Standard Set ◽  
Human Health Effects

Abstract. Exposure to nitrogen dioxide (NO2) is associated with negative human health effects, both for short-term peak concentrations and from long-term exposure to a wider range of NO2 concentrations. For the latter, the European Union has established an air quality limit value of 40 µg m−3 as an annual average. However, factors such as proximity and strength of local emissions, atmospheric chemistry and meteorological conditions means that there is substantial variation in the hourly NO2 concentrations contributing to an annual average concentration. The aim of this analysis was to quantify the nature of this variation at thousands of monitoring sites across Europe through the calculation of a standard set of chemical climatology statistics. Specifically, at each monitoring site that satisfied data capture criteria for inclusion in this analysis, annual NO2 concentrations, as well as the percentage contribution from each month, hour of the day, and hourly NO2 concentrations divided into 5 µg m−3 bins were calculated. Across Europe, 2010–2014 average annual NO2 concentrations (NO2AA) exceeded the annual NO2 limit value at 8 % of > 2500 monitoring sites. The application of this chemical climatology approach showed that sites with distinct monthly, hour of day, and hourly NO2 concentration bin contributions to NO2AA were not grouped in specific regions of Europe, and within relatively small geographic regions there were sites with similar NO2AA, but with differences in these contributions. Specifically, at sites with highest NO2AA, there were generally similar contributions from across the year, but there were also differences in the contribution of peak vs moderate hourly NO2 concentrations to NO2AA, and from different hours across the day. Trends between 2000 and 2014 for 259 sites indicate that, in general, the contribution to NO2AA from winter months has increased, as has the contribution from the rush-hour periods of the day, while the contribution from peak hourly NO2 concentrations has decreased. The variety of monthly, hour of day and hourly NO2 contribution bin contributions to NO2AA, across cities, countries and regions of Europe indicate that within relatively small geographic areas different interactions between emissions, atmospheric chemistry and meteorology produce variation in NO2AA and the conditions that produce it. Therefore, measures implemented to reduce NO2AA in one location may not be as effective in others. The development of strategies to reduce NO2AA for an area should consider i) the variation in monthly, hour of day and hourly NO2 concentration bin contributions to NO2AA within that area, and ii) how specific mitigation actions will affect variability in hourly NO2 concentrations.

scholarly journals An optimized tracer-based approach for estimating organic carbon emissions from biomass burning in Ulaanbaatar, Mongolia

2020 ◽  
Vol 20 (5) ◽  
pp. 3231-3247 ◽  
Author(s):  
Jayant Nirmalkar ◽  
Tsatsral Batmunkh ◽  
Jinsang Jung
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Quantitative Estimation ◽  
Water Soluble ◽  
Atmospheric Particulate Matter ◽  
Coefficient Of Determination ◽  
Urban Site ◽  
Air Sampler ◽  
Novel Approach ◽  
The Impact

Abstract. The impact of biomass burning (BB) on atmospheric particulate matter of <2.5 µm diameter (PM2.5) at Ulaanbaatar, Mongolia, was investigated using an optimized tracer-based approach during winter and spring 2017. Integrated 24 h PM2.5 samples were collected on quartz-fiber filters using a 30 L min−1 air sampler at an urban site in Ulaanbaatar. The aerosol samples were analyzed for organic carbon (OC) and elemental carbon (EC), anhydrosugars (levoglucosan, mannosan, and galactosan), and water-soluble ions. OC was found to be the predominant species, contributing 64 % and 56 % to the quantified aerosol components in PM2.5 in winter and spring, respectively. BB was identified as a major source of PM2.5, followed by dust and secondary aerosols. Levoglucosan ∕ mannosan and levoglucosan ∕ K+ ratios indicate that BB in Ulaanbaatar mainly originated from the burning of softwood. Because of the large uncertainty associated with the quantitative estimation of OC emitted from BB (OCBB), a novel approach was developed to optimize the OC ∕ levoglucosan ratio for estimating OCBB. The optimum OC ∕ levoglucosan ratio in Ulaanbaatar was obtained by regression analysis between OCnon-BB (OCtotal–OCBB) and levoglucosan concentrations that gives the lowest coefficient of determination (R2) and slope. The optimum OC ∕ levoglucosan ratio was found to be 27.6 and 18.0 for winter and spring, respectively, and these values were applied in quantifying OCBB. It was found that 68 % and 63 % of the OC were emitted from BB during winter and spring, respectively. This novel approach can also be applied by other researchers to quantify OCBB using their own chemical measurements. In addition to OCBB, sources of OCnon-BB were also investigated through multivariate correlation analysis. It was found that OCnon-BB originated mainly from coal burning, vehicles, and vegetative emissions.

scholarly journals Chemical characteristics and causes of airborne particulate pollution in warm seasons in Wuhan, central China

2016 ◽  
Vol 16 (16) ◽  
pp. 10671-10687 ◽  
Author(s):  
Xiaopu Lyu ◽  
Nan Chen ◽  
Hai Guo ◽  
Lewei Zeng ◽  
Weihao Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Mineral Elements ◽  
Average Concentration ◽  
Central China ◽  
National Standard ◽  
Urban Site ◽  
Chemical Compositions ◽  
Sampling Campaign ◽  
Secondary Organic Carbon

Abstract. Continuous measurements of airborne particles and their chemical compositions were conducted in May, June, October, and November 2014 at an urban site in Wuhan, central China. The results indicate that particle concentrations remained at a relatively high level in Wuhan, with averages of 135.1 ± 4.4 (mean ± 95 % confidence interval) and 118.9 ± 3.7 µg m−3 for PM10 and 81.2 ± 2.6 and 85.3 ± 2.6 µg m−3 for PM2.5 in summer and autumn, respectively. Moreover, PM2.5 levels frequently exceeded the National Standard Level II (i.e., daily average of 75 µg m−3), and six PM2.5 episodes (i.e., daily PM2.5 averages above 75 µg m−3 for 3 or more consecutive days) were captured during the sampling campaign. Potassium was the most abundant element in PM2.5, with an average concentration of 2060.7 ± 82.3 ng m−3; this finding indicates intensive biomass burning in and around Wuhan during the study period, because almost no correlation was found between potassium and mineral elements (iron and calcium). The source apportionment results confirm that biomass burning was the main cause of episodes 1, 3, and 4, with contributions to PM2.5 of 46.6 % ± 3.0 %, 50.8 % ± 1.2 %, and 44.8 % ± 2.6%, respectively, whereas fugitive dust was the leading factor in episode 2. Episodes 5 and 6 resulted mainly from increases in vehicular emissions and secondary inorganic aerosols, and the mass and proportion of NO3− both peaked during episode 6. The high levels of NOx and NH3 and the low temperature during episode 6 were responsible for the increase of NO3−. Moreover, the formation of secondary organic carbon was found to be dominated by aromatics and isoprene in autumn, and the contribution of aromatics to secondary organic carbon increased during the episodes.

scholarly journals Fossil and non-fossil sources of organic carbon (OC) and elemental carbon (EC) in Göteborg, Sweden

2009 ◽  
Vol 9 (5) ◽  
pp. 1521-1535 ◽  
Author(s):  
S. Szidat ◽  
M. Ruff ◽  
N. Perron ◽  
L. Wacker ◽  
H.-A. Synal ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Elemental Carbon ◽  
Latin Hypercube Sampling ◽  
Water Soluble ◽  
Total Carbon ◽  
Rural Site ◽  
Urban Site ◽  
Winter Period ◽  
Back Trajectories ◽  
Wood Burning

Abstract. Particulate matter was collected at an urban site in Göteborg (Sweden) in February/March 2005 and in June/July 2006. Additional samples were collected at a rural site for the winter period. Total carbon (TC) concentrations were 2.1–3.6 μg m−3, 1.8–1.9 μg m−3, and 2.2–3.0 μg m−3 for urban/winter, rural/winter, and urban/summer conditions, respectively. Elemental carbon (EC), organic carbon (OC), water-insoluble OC (WINSOC), and water-soluble OC (WSOC) were analyzed for 14C in order to distinguish fossil from non-fossil emissions. As wood burning is the single major source of non-fossil EC, its contribution can be quantified directly. For non-fossil OC, the wood-burning fraction was determined independently by levoglucosan and 14C analysis and combined using Latin-hypercube sampling (LHS). For the winter period, the relative contribution of EC from wood burning to the total EC was >3 times higher at the rural site compared to the urban site, whereas the absolute concentrations of EC from wood burning were elevated only moderately at the rural compared to the urban site. Thus, the urban site is substantially more influenced by fossil EC emissions. For summer, biogenic emissions dominated OC concentrations most likely due to secondary organic aerosol (SOA) formation. During both seasons, a more pronounced fossil signal was observed for Göteborg than has previously been reported for Zurich, Switzerland. Analysis of air mass origin using back trajectories suggests that the fossil impact was larger when local sources dominated, whereas long-range transport caused an enhanced non-fossil signal. In comparison to other European locations, concentrations of levoglucosan and other monosaccharide anhydrides were low for the urban and the rural site in the area of Göteborg during winter.

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