Mass concentrations, seasonal variations, chemical compositions and element sources of PM10 at an urban site in Constantine, northeast Algeria

2019 ◽  
Vol 206 ◽  
pp. 106356 ◽  
Author(s):  
F. Bencharif-Madani ◽  
H. Ali-Khodja ◽  
A. Kemmouche ◽  
A. Terrouche ◽  
K. Lokorai ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Urban Site ◽  
Chemical Compositions ◽  
Mass Concentrations

scholarly journals Characteristics of PM2.5 Chemical Compositions and Their Effect on Atmospheric Visibility in Urban Beijing, China during the Heating Season

2018 ◽  
Vol 15 (9) ◽  
pp. 1924 ◽  
Author(s):  
Xing Li ◽  
Shanshan Li ◽  
Qiulin Xiong ◽  
Xingchuan Yang ◽  
Mengxi Qi ◽  
...  
Keyword(s):  
Fine Particles ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Motor Vehicles ◽  
Urban Site ◽  
Chemical Compositions ◽  
Heating Season ◽  
Atmospheric Visibility ◽  
Visibility Impairment ◽  
Mass Concentrations

Beijing, which is the capital of China, suffers from severe Fine Particles (PM2.5) pollution during the heating season. In order to take measures to control the PM2.5 pollution and improve the atmospheric environmental quality, daily PM2.5 samples were collected at an urban site from 15 November to 31 December 2016, characteristics of PM2.5 chemical compositions and their effect on atmospheric visibility were analyzed. It was found that the daily average mass concentrations of PM2.5 ranged from 7.64 to 383.00 μg m−3, with an average concentration of 114.17 μg m−3. On average, the Organic Carbon (OC) and Elemental Carbon (EC) contributed 21.39% and 5.21% to PM2.5, respectively. Secondary inorganic ions (SNA: SO42− + NO3− + NH4+) dominated the Water-Soluble Inorganic Ions (WSIIs) and they accounted for 47.09% of PM2.5. The mass concentrations of NH4+, NO3− and SO42− during the highly polluted period were 8.08, 8.88 and 6.85 times greater, respectively, than during the clean period, which contributed most to the serious PM2.5 pollution through the secondary transformation of NO2, SO2 and NH3. During the highly polluted period, NH4NO3 contributed most to the reconstruction extinction coefficient (b′ext), accounting for 35.7%, followed by (NH4)2SO4 (34.44%) and Organic Matter (OM: 15.24%). The acidity of PM2.5 in Beijing was weakly acid. Acidity of PM2.5 and relatively high humidity could aggravate PM2.5 pollution and visibility impairment by promoting the generation of secondary aerosol. Local motor vehicles contributed the most to NO3−, OC, and visibility impairment in urban Beijing. Other sources of pollution in the area surrounding urban Beijing, including coal burning, agricultural sources, and industrial sources in the Hebei, Shandong, and Henan provinces, released large amounts of SO2, NH3, and NO2. These, which were transformed into SO42−, NH4+, and NO3− during the transmission process, respectively, and had a great impact on atmospheric visibility impairment.

scholarly journals Impact of particle number and mass size distributions of major chemical components on particle mass scattering efficiency in urban Guangzhou in southern China

2019 ◽  
Vol 19 (13) ◽  
pp. 8471-8490 ◽  
Author(s):  
Jun Tao ◽  
Zhisheng Zhang ◽  
Yunfei Wu ◽  
Leiming Zhang ◽  
Zhijun Wu ◽  
...  
Keyword(s):  
Size Distribution ◽  
Southern China ◽  
Chemical Species ◽  
Particle Mass ◽  
Urban Site ◽  
Chemical Compositions ◽  
Scattering Efficiency ◽  
Coarse Mode ◽  
Major Chemical ◽  
Mass Concentrations

Abstract. To grasp the key factors affecting particle mass scattering efficiency (MSE), particle mass and number size distribution, PM2.5 and PM10 and their major chemical compositions, and the particle scattering coefficient (bsp) under dry conditions were measured at an urban site in Guangzhou, southern China, during 2015–2016. On an annual average, 10±2 %, 48±7 % and 42±8 % of PM10 mass were in the condensation, droplet and coarse modes, respectively, with mass mean aerodynamic diameters (MMADs) of 0.78±0.07 in the droplet mode and 4.57±0.42 µm in the coarse mode. The identified chemical species mass concentrations can explain 79±3 %, 82±6 % and 57±6 % of the total particle mass in the condensation, droplet and coarse mode, respectively. Organic matter (OM) and elemental carbon (EC) in the condensation mode, OM, (NH4)2SO4, NH4NO3, and crustal element oxides in the droplet mode, and crustal element oxides, OM, and CaSO4 in the coarse mode, were the dominant chemical species in their respective modes. The measured bsp can be reconstructed to the level of 91±10 % using Mie theory with input of the estimated chemically resolved number concentrations of NaCl, NaNO3, Na2SO4, NH4NO3, (NH4)2SO4, K2SO4, CaSO4, Ca(NO3)2, OM, EC, crustal element oxides and unidentified fraction. MSEs of particle and individual chemical species were underestimated by less than 13 % in any season based on the estimated bsp and chemical species mass concentrations. Seasonal average MSEs varied in the range of 3.5±0.1 to 3.9±0.2 m2 g−1 for fine particles (aerodynamic diameter smaller than 2.1 µm), which was mainly caused by seasonal variations in the mass fractions and MSEs of the dominant chemical species (OM, NH4NO3, (NH4)2SO4) in the droplet mode. MSEs of the dominant chemical species were determined by their lognormal size-distribution parameters, including MMADs and standard deviation (σ) in the droplet mode.

scholarly journals Impact of particle number and mass size distributions of major chemical components on particle mass scattering efficiency in urban Guangzhou of South China

2019 ◽  
Author(s):  
Jun Tao ◽  
Zhisheng Zhang ◽  
Yunfei Wu ◽  
Leiming Zhang ◽  
Zhijun Wu ◽  
...  
Keyword(s):  
South China ◽  
Chemical Species ◽  
Particle Mass ◽  
Urban Site ◽  
Chemical Compositions ◽  
Small Range ◽  
Scattering Efficiency ◽  
Coarse Mode ◽  
Major Chemical ◽  
Mass Concentrations

Abstract. To grasp the key factors affecting particle mass scattering efficiency (MSE), particle mass and number size distribution, bulk PM2.5 and PM10 and their major chemical compositions, and particle scattering coefficient (bsp) under dry condition were measured at an urban site in Guangzhou, south China during 2015–2016. On annual average, 10 ± 2 %, 48 ± 7 % and 42 ± 8 % of PM10 mass were in the condensation, droplet and coarse modes, with mass median aerodynamic diameters (MMADs) of 0.21 ± 0.00, 0.78 ± 0.07 and 4.57 ± 0.42 μm, respectively. The identified chemical species mass concentrations can explain 79 ± 3 %, 82 ± 6 % and 57 ± 6 % of the total particle mass in the condensation, droplet and coarse mode, respectively. Organic matter (OM) and elemental carbon (EC) in the condensation mode, OM, (NH4)2SO4, NH4NO3 and crustal element oxides in the droplet mode, and crustal element oxides, OM and CaSO4 in the coarse mode were the dominant chemical species in their respective modes. The measured bsp can be reconstructed to the level of 91 ± 10 % using Mie theory with input of the estimated chemically-resolved number concentrations of NaCl, NaNO3, Na2SO4, NH4NO3, (NH4)2SO4, K2SO4, CaSO4, Ca(NO3)2, OM, EC, crustal element oxides and unidentified fraction. MSEs of bulk particle and individual chemical species were underestimated by less than 13 % in any season based on the estimated bsp and chemical species mass concentrations. Seasonal average MSEs varied in a small range of 3.5 ± 0.1 to 3.9 ± 0.2 m2 g−1 for fine particles, which was mainly caused by seasonal variations of the mass fractions and MSEs of OM in the droplet mode.

scholarly journals Spatial and Seasonal Variations of PM Concentration and Size Distribution in Manure-Belt Poultry Layer Houses

2019 ◽  
Vol 62 (2) ◽  
pp. 415-427 ◽  
Author(s):  
Reyna M. Knight ◽  
Xinjie Tong ◽  
Zhenyu Liu ◽  
Sewoon Hong ◽  
Lingying Zhao
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Size Distribution ◽  
Seasonal Variations ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Potential Health ◽  
Significant Difference ◽  
Autumn And Winter ◽  
Mass Concentrations

Abstract. Poultry layer houses are a significant source of particulate matter (PM) emissions, which potentially affect worker and animal health. Particulate matter characteristics, such as concentration and size distribution inside layer houses, are critical information for assessment of the potential health risks and development of effective PM mitigation technologies. However, this information and its spatial and seasonal variations are lacking for typical layer facilities. In this study, two TSI DustTrak monitors (DRX 8533) and an Aerodynamic Particle Sizer (APS 3321) were used to measure PM mass concentrations and number-weighted particle size distributions in two typical manure-belt poultry layer houses in Ohio in three seasons: summer, autumn, and winter. Bimodal particle size distributions were consistently observed. The average count median diameters (mean ±SD) were 1.68 ±0.25, 2.16 ±0.31, and 1.87 ±0.07 µm in summer, autumn, and winter, respectively. The average geometric standard deviations of particle size were 2.16 ±0.23, 2.16 ±0.18, and 1.74 ±0.17 in the three seasons, respectively. The average mass concentrations were 67.4 ±54.9, 289.9 ±216.2, and 428.1 ±269.9 µg m-3 for PM2.5; 73.6 ±59.5, 314.6 ±228.9, and 480.8 ±306.5 µg m-3 for PM4; and 118.8 ±99.6, 532.5 ±353.0, and 686.2 ±417.7 µg m-3 for PM10 in the three seasons, respectively. Both statistically significant (p < 0.05) and practically significant (difference of means >20% of smaller value) seasonal variations were observed. Spatial variations were only practically significant for autumn mass concentrations, likely due to external dust infiltration from nearby agricultural activities. The OSHA-mandated permissible exposure limit for respirable PM was not exceeded in any season. Keywords: Air quality, Particulate matter, Poultry housing, Seasonal variation, Spatial variation.

scholarly journals Synergistic effect of water-soluble species and relative humidity on morphological changes in aerosol particles in the Beijing megacity during severe pollution episodes

2019 ◽  
Vol 19 (1) ◽  
pp. 219-232 ◽  
Author(s):  
Xiaole Pan ◽  
Baozhu Ge ◽  
Zhe Wang ◽  
Yu Tian ◽  
Hang Liu ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Synergistic Effect ◽  
Mineral Dust ◽  
Water Soluble ◽  
Dust Particles ◽  
Urban Site ◽  
Chemical Compositions ◽  
Aerodynamic Diameter ◽  
Soluble Species ◽  
Pollution Episodes

Abstract. Depolarization ratio (δ) of backscattered light is an applicable parameter for distinguishing the sphericity of particles in real time, which has been widely adopted by ground-based lidar observation systems. In this study, δ values of particles and chemical compositions in both PM2.5 (aerodynamic diameter less than 2.5 µm) and PM10 (aerodynamic diameter less than 10 µm) were concurrently measured on the basis of a bench-top optical particle counter with a polarization detection module (POPC) and a continuous dichotomous aerosol chemical speciation analyzer (ACSA-14) from November 2016 to February 2017 at an urban site in Beijing megacity. In general, measured δ values depended on both size and sphericity of the particles. During the observation period, mass concentrations of NO3- in PM2.5 (fNO3) were about an order of magnitude higher than that in PM2.5−10 (cNO3) with a mean fNO3∕cNO3 ratio of 14±10. A relatively low fNO3∕cNO3 ratio (∼5) was also observed under higher relative humidity conditions, mostly due to heterogeneous processes and particles in the coarse mode. We found that δ values of ambient particles in both PM2.5 and PM2.5−10 obviously decreased as mass concentration of water-soluble species increased at unfavorable meteorological conditions. This indicated that the morphology of particles was changed as a result of water-absorbing processes. The particles with optical size (Dp) of Dp = 5 µm were used to represent mineral dust particles, and its δ values (δDp=5) decreased by 50 % as the mass fraction of cNO3 increased from 2 % to 8 % and ambient relative humidity increased up to 80 %, suggesting that mineral dust particles were likely to be spherical during humid pollution episodes. During the observation, relative humidity inside the POPC measuring chamber was stable at 34±2 %, lower than the ambient condition. Its influence on the morphology was estimated to be limited and did not change our major conclusion. This study highlights the evident alteration of non-sphericity of mineral dust particles during their transport owing to a synergistic effect of both pollutant coatings and hygroscopic processes, which plays an important role in the evaluation of its environmental effect.

Characteristics of Non-Methane Hydrocarbons in the Atmosphere of Guangzhou

2011 ◽  
Vol 66-68 ◽  
pp. 59-64
Author(s):  
Long Feng Li ◽  
Xin Ming Wang
Keyword(s):  
Local Time ◽  
Aromatic Hydrocarbons ◽  
Seasonal Variations ◽  
Urban Site ◽  
Diurnal Pattern ◽  
Air Samples ◽  
Mixing Ratios

From March to December 2005 NMHCs were measured in an urban site in Guangzhou. Air samples were collected with canister and analyzed for HMHCs by GC-MSD/FID after cryogenic pre-concentration. Mixing ratios of Alkanes accounted for over 43% in total NMHCs in each month while the shares of aromatic hydrocarbons were 19-28%. In average ethyne was the most abundant compound (5.46 ppbv), followed by propane (4.49 ppbv) and toluene (4.19 ppbv). Seasonal variations of most anthropogenic hydrocarbons revealed higher mixing ratios in autumn-winter than in spring-summer. Isoprene, on the contrary, exhibited the the highest levels in summer and the lowest in spring. Anthropogenic NMHCs typically showed a first peak around 8:00 local time in morning and 20:00 local time in the evening, while isoprene revealed a different bimodal diurnal pattern.

scholarly journals Characteristics of PM<sub>2.5</sub> mass concentrations and chemical species in urban and background areas of China: emerging results from the CARE-China network

2018 ◽  
Author(s):  
Zirui Liu ◽  
Wenkang Gao ◽  
Yangchun Yu ◽  
Bo Hu ◽  
Jinyuan Xin ◽  
...  
Keyword(s):  
Chemical Species ◽  
Central China ◽  
Research Network ◽  
Mitigation Measures ◽  
Chemical Components ◽  
Chemical Compositions ◽  
East Central ◽  
Urban Sites ◽  
Mass Concentrations

Abstract. The Campaign on atmospheric Aerosol REsearch network of China (CARE-China) is a long-term project for the study of the spatiotemporal distributions of physical aerosol characteristics as well as the chemical components and optical properties of aerosols over China. This study presents the first long-term datasets from this project, including three years of observations of online PM2.5 mass concentrations (2012–2014) and one year of observations of PM2.5 compositions (2012–2013) from the CARE-China network. The average PM2.5 concentrations at 20 urban sites is 73.2 μg/m3 (16.8–126.9 μg/m3), which was three times higher than the average value from the 12 background sites (11.2–46.5 μg/m3). The PM2.5 concentrations are generally higher in east-central China than in the other parts of the country due to their relative large particulate matter (PM) emissions and the unfavorable meteorological conditions for pollution dispersion. A distinct seasonal variability of the PM2.5 is observed, with highs in the winter and lows during the summer at urban sites. Inconsistent seasonal trends were observed at the background sites. Bimodal and unimodal diurnal variation patterns were identified at both urban and background sites. The chemical compositions of PM2.5 at six paired urban and background sites located within the most polluted urban agglomerations and cleanest regions of China were analyzed. The major PM2.5 constituents across all the urban sites are organic matter (OM, 26.0 %), SO42− (17.7 %), mineral dust (11.8 %), NO3− (9.8 %), NH4+ (6.6 %), elemental carbon (EC) (6.0 %), Cl− (1.2 %) at 45 % RH and residual matter (20.7 %). Similar chemical compositions of PM2.5 were observed at background sites but were associated with higher fractions of OM (33.2 %) and lower fractions of NO3− (8.6 %) and EC (4.1 %). Significant variations of the chemical species were observed among the sites. At the urban sites, the OM ranged from 12.6 μg/m3 (Lhasa) to 23.3 μg/m3 (Shenyang), the SO42− ranged from 0.8 μg/m3 (Lhasa) to 19.7 μg/m3 (Chongqing), the NO3− ranged from 0.5 μg/m3 (Lhasa) to 11.9 μg/m3 (Shanghai) and the EC ranged from 1.4 μg/m3 (Lhasa) to 7.1 μg/m3 (Guangzhou). The PM2.5 chemical species at the background sites exhibited larger spatial heterogeneities than those at urban sites, suggesting the different contributions from regional anthropogenic or natural emissions and from the long-range transport to background areas. Notable seasonal variations of PM2.5 polluted days were observed, especially for the megacities in east-central China, resulting in frequent heavy pollution episodes occurring during the winter. The evolution of the PM2.5 chemical compositions on polluted days was similar for the urban and nearby background sites, suggesting the significant regional pollution characteristics of the most polluted areas of China. However, the chemical species dominating the evolutions of the heavily polluted events were different in these areas, indicating that unique mitigation measures should be developed for different regions of China. This analysis reveals the spatial and seasonal variabilities of the urban and background aerosol concentrations on a national scale and provides insights into their sources, processes, and lifetimes.

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 Variations of cloud condensation nuclei (CCN) and aerosol activity during fog–haze episode: a case study from Shanghai

2014 ◽  
Vol 14 (22) ◽  
pp. 12499-12512 ◽  
Author(s):  
C. Leng ◽  
Q. Zhang ◽  
D. Zhang ◽  
C. Xu ◽  
T. Cheng ◽  
...  
Keyword(s):  
Cloud Condensation Nuclei ◽  
Great Influence ◽  
Urban Site ◽  
Chemical Compositions ◽  
Condensation Nuclei ◽  
Anthropogenic Pollutants ◽  
Clear Case ◽  
Haze Episode ◽  
Aerosol Fraction ◽  
Clear Cases

Abstract. Measurements of cloud condensation nuclei (CCN), condensation nuclei (CN) and aerosol chemical composition were performed simultaneously at an urban site in Shanghai from 6 to 9 November 2010. The variations of CCN number concentration (NCCN) and aerosol activity (activated aerosol fraction, NCCN/NCN) were examined during a fog–haze co-occurring event. Anthropogenic pollutants emitted from vehicles and unfavorable meteorological conditions such as low planetary boundary layer (PBL) height exerted a great influence on PM2.5 and black carbon (BC) loadings. NCCN at 0.2% supersaturation (SS) mostly fell in the range of 994 to 6268 cm−3, and the corresponding NCCN/NCN varied between 0.09 and 0.57. NCCN and NCCN/NCN usually were usually higher in the hazy case due to increased aerosol concentration in the accumulation mode (100–500 nm), and lower in the foggy–hazy and clear cases. The BC mass concentration posed a strong positive effect on NCCN in the foggy–hazy and hazy cases, whereas it poorly correlated with NCCN in the clear case. NCCN/NCN was weakly related with BC in both foggy–hazy and hazy cases. By using a simplified particle hygroscopicity (κ), the calculated critical dry size (CDS) of activated aerosol did not exceed 130 nm at 0.2% SS in spite of diverse aerosol chemical compositions. The predicted NCCN at 0.2% SS was very successful compared with the observed NCCN in clear case (R2=0.96) and foggy–hazy/hazy cases (R2=0.91). In addition, their corresponding ratios of predicted to observed NCCNwere on average 0.95 and 0.92, respectively. More organic matter is possibly responsible for this closure difference between foggy–hazy/hazy and clear cases. These results reveal that the particulate pollutant burden exerts a significant impact on NCCN, especially NCCN/NCN promotes effectively during the polluted periods.

Sign in / Sign up

Export Citation Format

Share Document