Cellulose in atmospheric particulate matter

Abstract. The spatiotemporal variations of free cellulose concentrations in atmospheric particles, as a proxy for plant debris, were investigated using a novel HPLC-PAD method. Filter samples were taken from nine sites of varying characteristics across France and Switzerland, with sampling covering all seasons. Concentrations of cellulose, as well as carbonaceous aerosol and other source-specific chemical tracers (e.g. Elemental Carbon (EC), levoglucosan, polyols, trace metals, and glucose) were quantified. Annual mean free cellulose concentrations within PM10 ranged from 29 ± 38 ng m−3 at Bern (urban site) to 284 ± 225 ng m−3 at Payerne (rural site). Concentrations were considerably higher during episodes, with spikes exceeding 1150 and 2200 ng m−3 at Payerne and ANDRA-OPE (rural site), respectively. A clear seasonality, with highest cellulose concentrations during summer and autumn, was observed at all rural and some urban sites. However, some urban locations exhibited a weakened seasonality. Contributions of cellulose-carbon to total organic carbon are moderate on average (0.7–5.9 %), but much greater during ‘episodes’, reaching close to 20 % at Payerne. Cellulose concentrations correlated poorly between sites, even a ranges of about 10 km, indicating the localised nature of the sources of atmospheric plant debris. With regards to these sources, correlations between cellulose and typical biogenic chemical tracers (polyols and glucose) were moderate to strong (Rs 0.28−0.78, p < 0.0001) across the nine sites. Seasonality was strongest at sites with stronger biogenic correlations, suggesting the main source of cellulose arises from biogenic origins. A second input to ambient plant debris concentrations was suggested via resuspension of plant matter at several urban sites, due to moderate cellulose correlations with mineral dust tracers, Ca2+ and Ti metal (Rs 0.28−0.45, p < 0.007). No correlation was obtained with the biomass burning tracer (levoglucosan), an indication that this is not a source of atmospheric cellulose. Finally, an investigation into the interannual variability of atmospheric cellulose across the Grenoble metropole area was completed. It was shown that concentrations and sources of ambient cellulose can vary considerably between years. All together, these results deeply improve our knowledge on the phenomenology of plant debris within ambient air.

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Spatio-Temporal Variation of Atmospheric Gaseous and Particulate Reactive Nitrogen over Northern India

Current World Environment ◽

10.12944/cwe.16.special-issue1.05 ◽

2021 ◽

Vol Special Issue (1) ◽

pp. 53-67

Author(s):

Manisha Mishra ◽

Umesh C Kulshrestha

Keyword(s):

Source Parameters ◽

Ambient Air ◽

Water Soluble ◽

Rural Site ◽

Urban Site ◽

Local Source ◽

Reactive Nitrogen ◽

Gangetic Plain ◽

Reactive N ◽

Spatio Temporal

The present study reports spatio-temporal distribution pattern of major gaseous (NH3 and NO2) and particulate water soluble total nitrogen (pWSTN) in the ambient air to explore the seasonal variation, major interactions and dominating sources. Considering the major hotspot of atmospheric reactive nitrogen (N) emission, three sites in Indo-Gangetic plain (IGP) were selected based on different local source parameters. Results have shown that gas phase reactive N contribute up to 90% of total analyzed reactive N, where NH3 imparted highest at all the three sites. Prayagraj, a fast growing urban site, has shown highest concentrations of NH3 (72.0 μg m−3), followed by Madhupur rural site (57.7 μg m−3) and Delhi, an urban megacity site (35.8 μg m−3). As compared to previous studies conducted at different sites of IGP, NH3 concentrations were reported to be the highest at the former two sites. However, unlike NH3, NO2 levels were recorded lower at Madhupur (3.1 μg m−3) and Prayagraj (9.4 μg m−3) sites as compared to Delhi (13.4 μg m−3). Similarly, pWSTN concentrations were in the order of Madhupur (6.6 μg m−3) < Prayagraj (10.0 μg m−3) < Delhi (10.1 μg m−3). A strong correlation of NO2 with pWSTN at urban sites has shown the crucial role of NO2 in the formation of nitrogenous aerosols. Significant spatial variation can be attributed to varying local emission sources ranging from microbial emission from improper sewage treatment and open waste dumping at Prayagraj, agricultural activities at Madhupur and vehicular exhausts at Delhi site.

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PM10 Chemical Profile during North African Dust Episodes over French West Indies

Atmosphere ◽

10.3390/atmos12020277 ◽

2021 ◽

Vol 12 (2) ◽

pp. 277

Author(s):

Philippe Quénel ◽

Jade Vadel ◽

Céline Garbin ◽

Séverine Durand ◽

Olivier Favez ◽

...

Keyword(s):

West Indies ◽

Rural Site ◽

Urban Site ◽

Chemical Profile ◽

North African ◽

French West Indies ◽

Specific Chemical ◽

Limit Values ◽

African Dust ◽

Emerging Pollutant

The French West Indies are periodically affected by North African dust episodes (NADE) resulting in PM10 concentrations exceeding air quality standards. The aim of the present study was to decipher the PM10 chemical profile during NADE over Guadeloupe. PM10 samples were collected daily at a rural site and an urban site during five episodes between April and October in 2017. During these events, the median PM10 mass concentrations were, on average, 2 to 5 times higher than in the post-episode baseline period. Sampled filters were analyzed for their quantification of chemical constituents including carbonaceous fractions (elemental and organic carbon, EC/OC), anions/cations and levoglucosan, 51 elements, and 57 selected organic species. An orthogonal partial least squares discriminant analysis (OPLS-DA) was conducted to identify the specific chemical profile of PM10 during NADE: 16 elements were identified as the most discriminant between the NADE and the control samples with mass concentration levels twice as high during a NADE. Among them, only two (Mn and V) are classified as emerging pollutant while no limit values exist for the other ones. The extensive characterization of the NADE PM10 chemical profile we performed is a key step to assess the chemical exposure of French West Indies populations during such events.

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Size-resolved aerosol composition at an urban and a rural site in the Po Valley in summertime: implications for secondary aerosol formation

10.5194/acp-2015-1036 ◽

2016 ◽

Cited By ~ 2

Author(s):

S. Sandrini ◽

D. van Pinxteren ◽

L. Giulianelli ◽

H. Herrmann ◽

L. Poulain ◽

...

Keyword(s):

Water Soluble ◽

Photochemical Oxidation ◽

Carbonaceous Aerosol ◽

Rural Site ◽

Urban Site ◽

Aerosol Formation ◽

Aerosol Composition ◽

Accumulation Mode ◽

Secondary Aerosol ◽

Po Valley

Abstract. The aerosol size-segregated chemical composition was analyzed at an urban (Bologna) and a rural site (San Pietro Capofiume) in the Po Valley, Italy, during June and July 2012, to investigate sources and mechanisms of secondary aerosol formation during the summer. A significant enhancement of secondary organic and inorganic aerosol mass was observed under anticyclonic conditions with recirculation of planetary boundary layer air, but with substantial differences between the urban and the rural site. The data analysis, including a Principal Component Analysis (PCA) on the size-resolved dataset of chemical concentrations, indicated that the photochemical oxidation of inorganic and organic gaseous precursors was an important mechanism of secondary aerosol formation at both sites. In addition at the rural site a second formation process, explaining the largest fraction (22 %) of the total variance, was active at night-time, especially under stagnant conditions. Nocturnal chemistry in the rural Po Valley was associated with the formation of ammonium nitrate in large accumulation mode (0.42–1.2 µm) aerosols favored by local thermodynamic conditions (higher relative humidity and lower temperature compared to the urban site). Nocturnal concentrations of fine nitrate were, in fact, on average five times higher at the rural site than in Bologna. The water uptake by this highly hygroscopic compound under high RH conditions provided the medium for increased nocturnal aerosol uptake of water soluble organic gases and possibly also for aqueous chemistry, as revealed by the shifting of peak concentrations of secondary compounds (WSOC and sulfate) toward the large accumulation mode (0.42–1.2 µm). Contrarily, the diurnal production of WSOC (proxy for secondary organic aerosol) by photochemistry was similar at the two sites but mostly affected the small accumulation mode of particles (0.14–0.42 µm) in Bologna, while a shift to larger accumulation mode was observed at the rural site. A significant increment in carbonaceous aerosol concentration (for both WSOC and WINC) at the urban site was recorded mainly in the size range 0.05–0.14 µm indicating a direct influence of traffic emissions on the mass concentrations of quasi-ultrafine particles.

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Persistent primary organic tar particles during the regional wintertime hazes in North China: insights into their aging and optical changes

10.5194/acp-2020-1012 ◽

2020 ◽

Author(s):

Lei Liu ◽

Jian Zhang ◽

Yinxiao Zhang ◽

Yuanyuan Wang ◽

Liang Xu ◽

...

Keyword(s):

Radiative Forcing ◽

Aging Process ◽

North China ◽

Clean Energy ◽

Rural Site ◽

Urban Site ◽

Average Particle ◽

Rural And Urban ◽

Lensing Effect ◽

Urban Sites

Abstract. Primary organic aerosol (POA) is a major component of PM2.5 in the winter polluted air in the North China Plain (NCP), but our understanding on the atmospheric aging process of POA particles and the resulting influences on their optical properties is limited. As part of the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-Beijing) programme, we collected airborne particles at an urban site (Beijing) and an upwind rural site (Gucheng, Hebei province) in the NCP during 13–27 November 2016 for microscopic analyses. We confirmed that a distinct group of spherical or irregular POA particles with high viscosity, defined as primary organic tar (POT) particles, was emitted from the domestic coal and biomass burning at the rural site and was further transported to the urban site during the regional wintertime hazes. During the heavily polluted period (PM2.5 > 200 μg m−3), more than 60 % of the POT particles were thickly coated with secondary inorganic aerosols (named as core–shell POT-SIA particle) through the aging process, suggesting that POT particles can provide surfaces for the heterogeneous reactions of SO2 and NOx. As a result, their average particle-to-core ratios at the rural and urban sites in the heavily polluted period increased to 1.60 and 1.67, respectively. Interestingly, we found that the aging process did not change the morphology and sizes of the POT cores, indicating that POT particles are quite inert in the atmosphere and can be transported long distances. We using the Mie theory estimated that the light absorption of individual POT particles was enhanced by ~ 1.39 times in the heavily polluted period at the rural and urban sites due to the lensing effect of secondary inorganic coatings. We highlight that the lensing effect on POT particles should be considered in radiative forcing models and the governments should continue to promote clean energy in rural areas to effectively reduce primary emissions.

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Persistent residential burning-related primary organic particles during wintertime hazes in North China: insights into their aging and optical changes

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-2251-2021 ◽

2021 ◽

Vol 21 (3) ◽

pp. 2251-2265

Author(s):

Lei Liu ◽

Jian Zhang ◽

Yinxiao Zhang ◽

Yuanyuan Wang ◽

Liang Xu ◽

...

Keyword(s):

Radiative Forcing ◽

Aging Process ◽

North China ◽

Clean Energy ◽

Rural Site ◽

Urban Site ◽

Average Particle ◽

Rural And Urban ◽

Lensing Effect ◽

Urban Sites

Abstract. Primary organic aerosols (POAs) are a major component of PM2.5 in winter polluted air in the North China Plain (NCP), but our understanding of the atmospheric aging processes of POA particles and the resulting influences on their optical properties is limited. As part of the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-Beijing) program, we collected airborne particles at an urban site (Beijing) and an upwind rural site (Gucheng, Hebei province) in the NCP during 13–27 November 2016 for microscopic analyses. We confirmed that large numbers of light-absorbing spherical POA (i.e., tarball) and irregular POA particles with high viscosity were emitted from domestic coal and biomass burning at the rural site and were further transported to the urban site during regional wintertime hazes. During the heavily polluted period (PM2.5 > 200 µg m−3), more than 60 % of these burning-related POA particles were thickly coated with secondary inorganic aerosols (named as core–shell POA–SIA particles) through the aging process, suggesting that POA particles can provide surfaces for the heterogeneous reactions of SO2 and NOx. As a result, during the heavily polluted period, their average particle-to-core diameter ratios at the rural and urban sites increased to 1.60 and 1.67, respectively. Interestingly, we found that the aging process did not change the morphology and sizes of POA cores, indicating that the burning-related POA particles are quite inert in the atmosphere and can be transported over long distances. Using Mie theory we estimated that the absorption capacity of these POA particles was enhanced by ∼ 1.39 times in the heavily polluted period at the rural and urban sites due to the “lensing effect” of secondary inorganic coatings. We highlight that the lensing effect on burning-related POA particles should be considered in radiative forcing models and authorities should continue to promote clean energy in rural areas to effectively reduce primary emissions.

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Representing the Urban Heat Island Effect in Future Climates

10.5194/egusphere-egu2020-1352 ◽

2020 ◽

Author(s):

Annkatrin Burgstall ◽

Ana Casanueva ◽

Elke Hertig ◽

Erich Fischer ◽

Reto Knutti ◽

...

Keyword(s):

Urban Heat Island ◽

Urban Areas ◽

Rural Site ◽

Urban Site ◽

Heat Island ◽

Hot Days ◽

Urban Heat ◽

Rural Sites ◽

Urban Sites

An increasing fraction of people living in urban areas and the expected increase in long lasting heat waves highlight the important role of urban climates in terms of future climate change impacts, especially with relation to the heat-health sector. Due to the urban heat island (UHI) effect and its (generally) increased intensity particularly during nighttime, people living in urban areas happen to be more affected by heat-related discomfort and health risks than those in non-urban regions. In this contribution, temperatures of both rural and urban sites (station couples) in Switzerland and Southern Germany are analyzed, using (i) observed as well as (ii) bias-corrected and downscaled climate model data for daily minimum (tmin) and daily maximum temperature (tmax) to account for the UHI in future climates. As meteorological data are often restricted to locations of long-term measurements at rural sites only, they need to be transferred to urban sites first. For this purpose, the well-established quantile mapping technique (QM) is tested in a two-step manner. The resulting products are urban time series at daily resolution for tmin and tmax. By analyzing the temperature differences of the observed climate at rural sites and their respective urban counterparts and by assuming a stationary relationship between both, we can represent the UHI in future climates, which is quantified in terms of heat indices based on tmin and tmax (tropical nights, summer days, hot days).The QM performance is evaluated using long-term weather station data of a Zurich station couple in a comprehensive cross-validation framework. Results reveal a promising performance in the present-day climate, given very low biases in the validation.Applying the proposed method to the employed station couples, projections indicate distinct urban-rural temperature differences (UHI) during nighttime (considering the frequency of tropical nights based on tmin) compared to weak differences during the day (considering the frequency of summer days and hot days based on tmax). Moreover, scenarios suggest the frequency of all indices to dramatically rise at the urban site by the end of the century under a strong emission scenario (RCP8.5): compared to the rural site, the number of tropical nights almost doubles while the number of summer days reveals about 15% more days at the urban site when focusing on the station couple in Zurich and the late scenario period. The lack of nighttime relief, indicated by tmin not falling below 20&#176;C (i.e. a tropical night), is especially problematic in terms of human health and makes the study of the urban climate in general and the UHI effect in particular indispensable.

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Size-resolved aerosol composition at an urban and a rural site in the Po Valley in summertime: implications for secondary aerosol formation

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-10879-2016 ◽

2016 ◽

Vol 16 (17) ◽

pp. 10879-10897 ◽

Cited By ~ 17

Author(s):

Silvia Sandrini ◽

Dominik van Pinxteren ◽

Lara Giulianelli ◽

Hartmut Herrmann ◽

Laurent Poulain ◽

...

Keyword(s):

Water Soluble ◽

Photochemical Oxidation ◽

Carbonaceous Aerosol ◽

Rural Site ◽

Urban Site ◽

Aerosol Formation ◽

Aerosol Composition ◽

Accumulation Mode ◽

Secondary Aerosol ◽

Po Valley

Abstract. The aerosol size-segregated chemical composition was analyzed at an urban (Bologna) and a rural (San Pietro Capofiume) site in the Po Valley, Italy, during June and July 2012, by ion-chromatography (major water-soluble ions and organic acids) and evolved gas analysis (total and water-soluble carbon), to investigate sources and mechanisms of secondary aerosol formation during the summer. A significant enhancement of secondary organic and inorganic aerosol mass was observed under anticyclonic conditions with recirculation of planetary boundary layer air but with substantial differences between the urban and the rural site. The data analysis, including a principal component analysis (PCA) on the size-resolved dataset of chemical concentrations, indicated that the photochemical oxidation of inorganic and organic gaseous precursors was an important mechanism of secondary aerosol formation at both sites. In addition, at the rural site a second formation process, explaining the largest fraction (22 %) of the total variance, was active at nighttime, especially under stagnant conditions. Nocturnal chemistry in the rural Po Valley was associated with the formation of ammonium nitrate in large accumulation-mode (0.42–1.2 µm) aerosols favored by local thermodynamic conditions (higher relative humidity and lower temperature compared to the urban site). Nocturnal concentrations of fine nitrate were, in fact, on average 5 times higher at the rural site than in Bologna. The water uptake by this highly hygroscopic compound under high RH conditions provided the medium for increased nocturnal aerosol uptake of water-soluble organic gases and possibly also for aqueous chemistry, as revealed by the shifting of peak concentrations of secondary compounds (water-soluble organic carbon (WSOC) and sulfate) toward the large accumulation mode (0.42–1.2 µm). Contrarily, the diurnal production of WSOC (proxy for secondary organic aerosol) by photochemistry was similar at the two sites but mostly affected the small accumulation mode of particles (0.14–0.42 µm) in Bologna, while a shift to larger accumulation mode was observed at the rural site. A significant increment in carbonaceous aerosol concentration (for both WSOC and water-insoluble carbon) at the urban site was recorded mainly in the quasi-ultrafine fraction (size range 0.05–0.14 µm), indicating a direct influence of traffic emissions on the mass concentrations of this range of particles.

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Persistent residential burning-related primary organic particles during wintertime hazes in North China: insights into their aging and optical changes

10.5194/egusphere-egu21-3796 ◽

2021 ◽

Author(s):

Lei Liu ◽

Jian Zhang ◽

Weijun Li

Keyword(s):

Radiative Forcing ◽

Aging Process ◽

North China ◽

Clean Energy ◽

Rural Site ◽

Urban Site ◽

Average Particle ◽

Rural And Urban ◽

Lensing Effect ◽

Urban Sites

Primary organic aerosol (POA) is a major component of PM2.5 in winter polluted air in the North China Plain (NCP), but our understanding on the atmospheric aging process of POA particles and the resulting influences on their optical properties is limited. As part of the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-Beijing) programme, we collected airborne particles at an urban site (Beijing) and an upwind rural site (Gucheng, Hebei province) in the NCP during 13&#8211;27 Nov. 2016 for microscopic analyses. We confirmed that large amounts of light-absorbing spherical POA (i.e., tarball) and irregular POA particles with high viscosity were emitted from the domestic coal and biomass burning at the rural site and were further transported to the urban site during regional wintertime hazes. During the heavily polluted period (PM2.5 > 200 &#956;g m&#8722;3), more than 60% of these burning-related POA particles were thickly coated with secondary inorganic aerosols (named as core&#8211;shell POA&#8211;SIA particle) through the aging process, suggesting that POA particles can provide surfaces for the heterogeneous reactions of SO2 and NOx. As a result, their average particle-to-core diameter ratios at the rural and urban sites in the heavily polluted period increased to 1.60 and 1.67, respectively. Interestingly, we found that the aging process did not change the morphology and sizes of POA cores, indicating that these POA particles are quite inert in the atmosphere and can be transported long distances. Using Mie theory we estimated that the absorption capacity of POA particles was enhanced by ~1.39 times in the heavily polluted period at the rural and urban sites due to the &#8220;lensing effect&#8221; of secondary inorganic coatings. We highlight that the &#8220;lensing effect&#8221; on burning-related POA particles should be considered in radiative forcing models and the governments should continue to promote clean energy in rural areas to effectively reduce primary emissions.

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Postharvest Burning of Crop Residues in Home Stoves in a Rural Site of Daejeon, Korea: Its Impact to Atmospheric Carbonaceous Aerosol

Atmosphere ◽

10.3390/atmos12020257 ◽

2021 ◽

Vol 12 (2) ◽

pp. 257

Author(s):

Jin Sang Jung ◽

Ji Hwan Kang

Keyword(s):

Urban Area ◽

Rural Area ◽

Crop Residues ◽

Sampling Period ◽

Carbonaceous Aerosol ◽

Rural Site ◽

Carbonaceous Aerosols ◽

High Concentration ◽

Crop Residue Burning ◽

The Impact

To investigate the impact of burning postharvest crop residues in home stoves, PM2.5 samples (particulate matter with a diameter of <2.5 μm) were collected every 3 h at a rural site in Daejeon, Korea during the postharvest season in 2014. A high concentration of levoglucosan was observed with a peak value of 3.8 µg/m3 during the sampling period. The average mannosan/levoglucosan ratio (0.18) at the rural site during a severe BB episode (levoglucosan > 1 μg/m3) was similar to burnings of pepper stems (0.19) and bean stems (0.18) whereas the average OC/levoglucosan ratio (9.9) was similar to burning of pepper stems (10.0), implying that the severe BB episode was mainly attributed to burning of pepper stems. A very strong correlation was observed between levoglucosan and organic carbon (OC) (R2 = 0.81) during the entire sampling period, suggesting that the emission of organic aerosols at the rural site was strongly associated with the burning of crop residues in home stoves. The average mannosan/levoglucosan ratio (0.17 ± 0.06) in the rural area was similar to that in a nearby urban area in Daejeon (0.16 ± 0.04). It was concluded that crop residue burning in a home stove for space heating is one of the important sources of carbonaceous aerosols not only in a rural area but also in the urban area of Daejeon, Korea during the postharvest season.

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Salt Intake in Nigeria: a nationwide population survey

European Heart Journal ◽

10.1093/ehjci/ehaa946.2866 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

A.N Odili ◽

B.S Chori ◽

B Danladi ◽

P.C Nwakile ◽

J.O Ogedengbe ◽

...

Keyword(s):

Salt Intake ◽

Sodium Intake ◽

Population Analysis ◽

Cost Effective ◽

Rural Site ◽

Urban Site ◽

Funding Source ◽

Salt Reduction ◽

High Salt Intake ◽

The Impact

Abstract Background Population wide salt reduction programmes are cost effective strategies for control of cardiovascular diseases (CVDs). Obtaining a nationwide salt consumption data in a multi-cultural setting as Nigeria's is key for proper implementation and monitoring of such strategy. Methods We measured sodium in 24-hour urine of free-living adult Nigerians selected from an urban and a rural site each from the 6 geopolitical zones of Nigeria to evaluate patterns of salt intake and its associations with blood pressures (BP). Results Across the 12 sites, sodium intake ranged from 97.9 in the rural South-South to 210 mmol/day in the urban site of the same zone. Overall, the median (IQR) daily sodium intake was 143.5 (97.8) mmol; with higher (p=0.0028) levels among the urban 149.7 (113.8) compared to the rural 133.1 (105.2) dwellers. Overall, 20% of the subjects consumed less than the recommended 2g (86mmol) of sodium daily. After adjustment for age, sex and BMI; sodium intake and BP (systolic and diastolic) were positively associated in 8 out of the 12 sites; significantly so in 2 (p<0.05) for systolic. Within population analysis; which included 973 individuals, increasing sodium intake tended (not significantly) to increase SBP but decrease DBP. However, among subjects whose sodium intake was in excess of 257mmol/day, a 100 mmol/day increase in sodium intake was significantly (p=0.04) associated with a 3.3 mmHg increase in SBP. Conclusion Salt intake among Nigerians is higher than the recommended. The impact of sodium intake on BP appears to be evident only among individuals with high salt intake. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Wellcome Trust

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