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Animals : An Open Access Journal From... Jul 2023This research shows the size composition of airborne dust fractions in selected dairy barns down to the smallest particles, including factors that influence this...
This research shows the size composition of airborne dust fractions in selected dairy barns down to the smallest particles, including factors that influence this composition. Measurements with a Dust-Track 8530 laser photometer took place in the summer at external temperatures of 29.5 to 36 °C. In barns with straw bedding, the average total dust concentration TDC was 66.98 ± 28.38 μg·m (PM 60.11 ± 19.93 μg·m, PM 49.48 ± 13.76 μg·m, PM 44.78 ± 10.18 μg·m, and PM 38.43 ± 9.29 μg·m). In barns without straw bedding, the average TDC was 55.91 ± 36.6 μg·m, PM 33.71 ± 13.86 μg·m, PM 30.69 ± 15.29 μg·m, PM 27.02 ± 13.38 μg·m, and PM 22.93 ± 10.48 μg·m. The largest TDC of 108.09 ± 32.93 μg·m (PM 69.80 ± 18.70 μg·m, PM 68.20 ± 18.41 μg·m, PM 53.27 ± 14.73 μg·m, and PM 38.46 ± 5.55 μg·m) was measured in an old cowshed with stanchion housing for 113 cows, straw bedding, and ventilation through windows. In a modern cowshed for loose housing of 440 lactating cows without straw bedding, with natural ventilation and 24 axial fans, TDC was 53.62 ± 49.52 μg·m, PM 20.91 ± 5.24 μg·m, PM 17.11 ± 3.23 μg·m, PM 13.71 ± 0.92 μg·m, and PM 12.69 ± 2.82 μg·m. In all investigated barns, a large proportion of airborne dust particles (54.38 ± 20.82% of TDC) consists of the smallest PM dust particles (from 12.69 ± 2.82 μg·m to 48.48 ± 1.18 μg·m).
PubMed: 37508099
DOI: 10.3390/ani13142322 -
Environment International Aug 2023This study analyzed the variability of equivalent black carbon (eBC) mass concentrations and their sources in urban Europe to provide insights into the use of eBC as an...
This study analyzed the variability of equivalent black carbon (eBC) mass concentrations and their sources in urban Europe to provide insights into the use of eBC as an advanced air quality (AQ) parameter for AQ standards. This study compiled eBC mass concentration datasets covering the period between 2006 and 2022 from 50 measurement stations, including 23 urban background (UB), 18 traffic (TR), 7 suburban (SUB), and 2 regional background (RB) sites. The results highlighted the need for the harmonization of eBC measurements to allow for direct comparisons between eBC mass concentrations measured across urban Europe. The eBC mass concentrations exhibited a decreasing trend as follows: TR > UB > SUB > RB. Furthermore, a clear decreasing trend in eBC concentrations was observed in the UB sites moving from Southern to Northern Europe. The eBC mass concentrations exhibited significant spatiotemporal heterogeneity, including marked differences in eBC mass concentration and variable contributions of pollution sources to bulk eBC between different cities. Seasonal patterns in eBC concentrations were also evident, with higher winter concentrations observed in a large proportion of cities, especially at UB and SUB sites. The contribution of eBC from fossil fuel combustion, mostly traffic (eBC) was higher than that of residential and commercial sources (eBC) in all European sites studied. Nevertheless, eBC still had a substantial contribution to total eBC mass concentrations at a majority of the sites. eBC trend analysis revealed decreasing trends for eBC over the last decade, while eBC remained relatively constant or even increased slightly in some cities.
Topics: Air Pollutants; Environmental Monitoring; Aerosols; Air Pollution; Europe; Seasons; Soot; Carbon; Particulate Matter
PubMed: 37451041
DOI: 10.1016/j.envint.2023.108081 -
Journal of Environmental Sciences... Oct 2023Black carbon (BC) aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation. The lifetime of BC depends...
Black carbon (BC) aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation. The lifetime of BC depends on atmospheric transport, aging and consequently on wet scavenging processes (in-cloud and below-cloud scavenging). In this study, sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer (SP2) and a nebulizer. The results showed that the volume-weighted average (VWA) mass concentrations of refractory black carbon (rBC) in each rainfall event varied, ranging from 10.8 to 78.9 µg/L. The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events. The geometric mean median mass-equivalent diameter (MMD) decreased under precipitation, indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging. A positive correlation (R = 0.73) between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process. Additionally, the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74% and 26% to wet scavenging, respectively. The scavenging ratio of rBC particles was estimated to be 0.06 on average. This study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.
Topics: Air Pollutants; Beijing; Soot; Aerosols; Carbon; Environmental Monitoring
PubMed: 37336608
DOI: 10.1016/j.jes.2022.07.039 -
Spectrochimica Acta. Part A, Molecular... Dec 2023Abnormal iron ions levels may lead to some diseases and serious environmental pollution. Herein, optical and visual detection strategies of Fe in water based on co-doped...
Abnormal iron ions levels may lead to some diseases and serious environmental pollution. Herein, optical and visual detection strategies of Fe in water based on co-doped carbon dots (CDs) were established in the present study. Firstly, a one-pot synthetic strategy for the preparation of the N, S, B co-doped CDs with a home microwave oven was developed. Secondly, the optical properties, chemical structures, and morphology of CDs were further characterized by fluorescence spectroscopy, Uv-vis absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscope. Finally, the results indicated that the fluorescence of the co-doped CDs was quenched by ferric ions via the static mechanism and the aggregation of CDs, accompanied by the increased red color. The multi-mode sensing strategies of Fe with fluorescence photometer, UV-visible spectrophotometer, portable colorimeter and smartphone had the advantages of good selectivity, excellent stability and high sensitivity. Fluorophotometry based on co-doped CDs was a powerful probe platform for measuring lower concentrations of Fe due to its higher sensitivity, better linear relationship, lower limit of detection (0.27 μM) and limit of quantitation (0.91 μM). In addition, the visual detection methods with a portable colorimeter and smartphone had been proven to be very suitable for rapid and simple sensing of higher concentrations of Fe. Moreover, the co-doped CDs utilized for Fe probes in tap water and boiler water obtained satisfactory results. Consequently, the efficient, versatile optical and visual multi-mode sensing platform could be extended to apply such a visual analysis of ferric ions in the biological, chemical and other fields.
PubMed: 37329831
DOI: 10.1016/j.saa.2023.122995 -
The Science of the Total Environment Sep 2023Considering the significance of PM aerosol in assessing health impacts of air pollution, an extensive analysis of PM samples collected at an urban site in Delhi is...
Considering the significance of PM aerosol in assessing health impacts of air pollution, an extensive analysis of PM samples collected at an urban site in Delhi is presented in this study. Overall, PM contributed to about 50 % of PM mass which is alarming especially in Delhi where particle mass loadings are usually higher than prescribed limits. Major portion of PM consisted of organic matter (OM) that formed nearly 47 % of PM mass. Elemental carbon (EC) contributed to about 13 % of PM mass, whereas SO (16 %), NH (10 %), NO (4 %) and Cl (3 %) were the major inorganic ions present. Sampling was performed in two distinctive campaign periods (in terms of meteorological conditions and heating (fire) activities), during the year 2019, each spanning two-week time, i.e. (i) September 3-16 (clean days), and (ii) November 22-December 5 (polluted days). Additionally, PM and black carbon (BC) were measured simultaneously for subsequent analysis. The 24-h averaged mean concentrations of PM and BC during clean days (polluted days) were 70.6 ± 26.9 and 3.9 ± 1.0 μg m (196 ± 104 and 7.6 ± 4.1 μg m), respectively, which were systematically lower (higher) than that of the annual mean (taken from studies conducted at same site in 2019) of 142 and 5.7 μg m, respectively. Changes in characteristic ratios (i.e., organic carbon (OC)/elemental carbon (EC) and K/EC) of chemical species detected in PM show an increase in biomass emissions during polluted days. Increase in biomass emission can be attributed to increase in heating practices (burning of biofuels such as wood logs, straw, and cow-dung cake) in- and around- Delhi because of fall in temperature during second campaign. Furthermore, a significant increase in NO fraction of PM is observed during second campaign which shows fog processing of NO due to conducive meteorological conditions in winters. Also, comparatively stronger correlation of NO with K during second campaign (r = 0.98 as compared to r = 0.5 during first campaign) suggests the increased heating practices to be a contributing factor for increased fraction of NO in PM. We observed that during polluted days, meteorological parameters such as dispersion rate also played a major role in intensifying the impact of increased local emissions due to heating activities. Apart from this, change in the direction of regional emission transport to study site and the topology of Delhi are the possible reasons for the elevated pollution level, especially PM during winter in Delhi. This study also suggests that black carbon measurement techniques used in current study (optical absorbance with heated inlet and evolved carbon techniques) can be used as reference techniques to determine the site-specific calibration constant of optical photometers for urban aerosol.
Topics: Particulate Matter; Air Pollutants; Environmental Monitoring; Seasons; Aerosols; Carbon; Soot; India
PubMed: 37225098
DOI: 10.1016/j.scitotenv.2023.164266 -
Ocular Immunology and Inflammation Nov 2023To evaluate the correlation between longitudinal changes in aqueous flare measured by laser flare photometer (LFP), best-corrected visual acuity (BCVA), and clinical...
PURPOSE
To evaluate the correlation between longitudinal changes in aqueous flare measured by laser flare photometer (LFP), best-corrected visual acuity (BCVA), and clinical grade using both Standardization of Uveitis Nomenclature (SUN) and modified SUN (MSUN) scales uveitis patients.
METHODS
Patients were classified according to both SUN and MSUN grading scales. LFP measurements were acquired (Kowa FM-700) at each visit. Mean change in LFP was assessed longitudinally, comparing with those in visual acuity, SUN, and MSUN grading scales.
RESULTS
Mean change in LFP was correlated to those in BCVA ( = .018), SUN scale ( < .001), and MSUN scale ( = .008). Cases within same initial SUN (0 and 1+) and MSUN (0.5+ and 1+) grades and different longitudinal flare prognosis (decreased/unchanged/increased) had significantly different initial LFP values (all < .05).
CONCLUSIONS
LFP measurement is beneficial in monitoring inflammatory activity. Cases of identical clinical flare scores with different clinical prognosis may be predicted by LFP.
Topics: Humans; Aqueous Humor; Uveitis, Anterior; Uveitis; Photometry; Lasers
PubMed: 36170559
DOI: 10.1080/09273948.2022.2123365