scholarly journals PM speciation and sources in Mexico during the MILAGRO-2006 Campaign

2007 ◽  
Vol 7 (4) ◽  
pp. 10589-10629 ◽  
Author(s):  
X. Querol ◽  
J. Pey ◽  
M. C. Minguillón ◽  
N. Pérez ◽  
A. Alastuey ◽  
...  
Keyword(s):  
Road Traffic ◽  
Principal Component ◽  
Coarse Fraction ◽  
Similar Proportion ◽  
Mineral Matter ◽  
Road Traffic Emissions ◽  
Pm10 And Pm2.5 ◽  
Local Soil ◽  
Rural Sites ◽  
Urban Sites

Abstract. Levels of PM10, PM2.5 and PM1 and chemical speciation of PM10 and PM2.5 were measured during the MILAGRO campaign (1 to 31 March 2006, but extended in some cases until 6 April) at four urban, one suburban, two rural, two rural background sites with different degree of industrial influence in the Mexico City Metropolitan Area (MCMA) and adjacent regions. PM10 and PM2.5 daily levels varied between 50–56 μg/m³ and 24–46 μg/m³ at the urban sites, 22–35 μg/m³ and 13–25 μg/m³ at the rural sites, and 75 μg/m³ and 31 $\\mu $g/m³ at the industrial hotspot, respectively; lower than those recorded at some Asian mega-cities and similar to those recorded at other South American cities. At the urban sites, hourly PM2.5 and PM1 concentrations showed a marked impact of road traffic emissions (at rush hours), with levels of coarse PM remaining elevated during daytime. At the suburban and rural sites, different PM daily patterns were registered according to the influence of the pollution plume from MCMA and also on local soil resuspension. The speciation studies showed that mineral matter accounted for 25–27% of bulk PM10 at the urban sites and a higher proportion (up to 43%) at the suburban and rural sites. This pattern is repeated in PM2.5, with 15% at urban and 28% at suburban and rural sites. Carbonaceous compounds accounted for a similar proportion at the urban sites (24–32% in PM10, and up to 37% in PM2.5), markedly reduced at the suburban and rural sites (17% in PM10, and 23–38% in PM2.5). The secondary inorganic aerosols accounted for 10–20% of bulk PM10 at urban, suburban, rural and industrial sites, with a higher proportion (40%) at the industrial background site. A relatively high proportion of nitrate in rural sites was present in the coarse fraction. Typically anthropogenic elements (As, Cr, Zn, Cu, Pb, Sn, Sb, Ba, among others) showed considerably high levels at the urban sites; however levels of particulate Hg and crustal trace elements (Rb, Ti, La, Sc, Ga) were generally higher at the suburban site. Principal component analysis identified three common factors: crustal, regional background and road traffic. Moreover, some specific factors were obtained for each site.

scholarly journals PM speciation and sources in Mexico during the MILAGRO-2006 Campaign

2008 ◽  
Vol 8 (1) ◽  
pp. 111-128 ◽  
Author(s):  
X. Querol ◽  
J. Pey ◽  
M. C. Minguillón ◽  
N. Pérez ◽  
A. Alastuey ◽  
...  
Keyword(s):  
Latin American ◽  
Road Traffic ◽  
Significant Proportion ◽  
Coarse Fraction ◽  
Mineral Matter ◽  
Industrial Sites ◽  
Pm10 And Pm2.5 ◽  
Local Soil ◽  
Rural Sites ◽  
Urban Sites

Abstract. Levels of PM10, PM2.5 and PM1 and chemical speciation of PM10 and PM2.5 were measured during the MILAGRO campaign (1st to 31st March 2006, but extended in some cases until 6th April) at four urban, one suburban, two rural background and two rural sites, with different degree of industrial influence, in the Mexico City Metropolitan Area (MCMA) and adjacent regions. PM10 and PM2.5 daily levels varied between 50–56μg/m3 and 24–46μg/m3 at the urban sites, 22–35μg/m3 and 13–25μg/m3 at the rural sites, and 75μg/m3 and 31μg/m3 at the industrial hotspot, lower than those recorded at some Asian mega-cities and similar to those recorded at other Latin American cities. At the urban sites, hourly PM2.5 and PM1 concentrations showed a marked impact of road traffic emissions (at rush hours), with levels of coarse PM remaining elevated during daytime. At the suburban and rural sites different PM daily patterns were registered according to the influence of the pollution plume from MCMA, and also of local soil resuspension. The speciation studies showed that mineral matter accounted for 25–27% of bulk PM10 at the urban sites and a higher proportion (up to 43%) at the suburban and rural sites. This pattern is repeated in PM2.5, with 15% at urban and 28% at suburban and rural sites. Carbonaceous compounds accounted for a significant proportion at the urban and industrial sites (32–46% in PM10, and 51–55% in PM2.5), markedly reduced at the suburban and rural sites (16–23% in PM10, and 30% in PM2.5). The secondary inorganic aerosols accounted for 10–20% of bulk PM10 at urban, suburban, rural and industrial sites, with a higher proportion (40%) at the industrial background site. A relatively high proportion of nitrate in rural sites was present in the coarse fraction. Typically anthropogenic elements (As, Cr, Zn, Cu, Pb, Sn, Sb, Ba, among others) showed considerably high levels at the urban sites; however levels of particulate Hg and crustal trace elements (Rb, Ti, La, Sc, Ga) were generally higher at the suburban site. Principal component analysis identified three major common factors: crustal, regional background and road traffic. Moreover, some specific factors were obtained for each site.

scholarly journals Two lichens differing in element concentrations have similar spatial patterns of element concentrations responding to road traffic and soil input

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuan-yuan Wu ◽  
Jing Gao ◽  
Guo-zhan Zhang ◽  
Run-kang Zhao ◽  
Ai-qin Liu ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Inner Mongolia ◽  
Element Concentration ◽  
Road Traffic ◽  
Enrichment Factors ◽  
Soil Samples ◽  
The Road ◽  
Element Concentrations ◽  
Road Traffic Emissions ◽  
Local Soil

Abstract Two epiphytic lichens (Xanthoria alfredii, XAa; X. ulophyllodes, XAu) and soil were sampled at three sites with varied distances to a road in a semiarid sandland in Inner Mongolia, China and analyzed for concentrations of 42 elements to assess the contribution of soil input and road traffic to lichen element burdens, and to compare element concentration differences between the two lichens. The study showed that multielement patterns, Fe:Ti and rare earth element ratios were similar between the lichen and soil samples. Enrichment factors (EFs) showed that ten elements (Ca, Cd, Co, Cu, K, P, Pb, S, Sb, and Zn) were enriched in the lichens relative to the local soil. Concentrations of most elements were higher in XAu than in XAa regardless of sites, and increased with proximity to the road regardless of lichen species. These results suggested that lichen element compositions were highly affected by soil input and road traffic. The narrow-lobed sorediate species were more efficient in particulate entrapment than the broad-lobed nonsorediate species. XAa and XAu are good bioaccumulators for road pollution in desert and have similar spatial patterns of element concentrations for most elements as response to road traffic emissions and soil input.

scholarly journals Variability of carbonaceous aerosols in remote, rural, urban and industrial environments in Spain: implications for air quality policy

2013 ◽  
Vol 13 (3) ◽  
pp. 6971-7019
Author(s):  
X. Querol ◽  
A. Alastuey ◽  
M. Viana ◽  
T. Moreno ◽  
C. Reche ◽  
...  
Keyword(s):  
Air Quality ◽  
Road Traffic ◽  
Mixing Layer ◽  
Gaseous Emissions ◽  
Carbonaceous Aerosols ◽  
Health Related ◽  
Remote Sites ◽  
Rural Sites ◽  
The Impact ◽  
Urban Sites

Abstract. We interpret here the variability of levels of carbonaceous aerosols based on a 12-yr database from 78 monitoring stations across Spain especially compiled for this article. Data did not evidence any spatial trends of carbonaceous aerosols across the country. Conversely, results show marked differences in average concentrations from the cleanest, most remote sites (around 1 μg m−3 of non-mineral carbon (nmC), mostly made of organic carbon (OC), with very little elemental carbon (EC) 0.1 μg m−3; OC/EC = 12–15), to the highly polluted major cities (8–10 μg m−3 of nmC; 3–4 μg m−3 of EC; 4–5 μg m−3 of OC; OC/EC = 1–2). Thus, urban (and very specific industrial) pollution was found to markedly increase levels of carbonaceous aerosols in Spain, with much lower impact of biomass burning. Correlations between yearly averaged OC/EC and EC concentrations adjust very well to a potential equation (OC/EC = 3.37 EC−0.67 R2 = 0.94). A similar equation is obtained when including average concentrations obtained at other European sites (y = 3.61x−0.5, R2 = 0.78). A clear seasonal variability in OC and EC concentrations was detected. Both OC and EC concentrations were higher during winter at the traffic and urban sites, but OC increased during the warmer months at the rural sites. Hourly equivalent black carbon (EBC) concentrations at urban sites accurately depict road traffic contributions, varying with distance to road, traffic volume and density, mixing layer height and wind speed. Weekday urban rush-hour EBC peaks are mimicked by concentrations of primary gaseous emissions from road traffic, whereas a single midday peak is characteristic of remote and rural sites. Decreasing annual trends for carbonaceous aerosols were observed between 1999 and 2011 at a large number of stations, probably reflecting the impact of the EURO4 and EURO5 standards in reducing the diesel PM emissions. This has resulted in some cases in an increasing trend of NO2/OC+EC ratios, because these standards have been much less effective for the abatement of NOx exhaust emissions in passenger diesel cars. This study concludes that EC, EBC, and especially nmC and OC+EC are very good candidates for new air quality standards since they cover both emission impact and health related issues.

scholarly journals Seasonal Variation, Chemical Composition, and PMF-Derived Sources Identification of Traffic-Related PM1, PM2.5, and PM2.5–10 in the Air Quality Management Region of Žilina, Slovakia

2021 ◽  
Vol 18 (19) ◽  
pp. 10191
Author(s):  
Dusan Jandacka ◽  
Daniela Durcanska
Keyword(s):  
Seasonal Variation ◽  
Urban Environment ◽  
Maximum Concentration ◽  
Inductively Coupled Plasma ◽  
Road Traffic ◽  
Fine Fraction ◽  
Gravimetric Method ◽  
Principal Component ◽  
Coarse Fraction ◽  
Over Time

Particulate matter (PM) air pollution in the urban environment is mainly related to the presence of potential sources throughout the year. Road transport is one of the most important sources of PM in the urban environment, because it directly affects pedestrians. PM measurements were performed in the city of Žilina, Slovakia, at various road-traffic-related measurement stations over the course of several years. This paper evaluates changes in the concentration of the fine fraction (PM2.5), the ultrafine fraction (PM1), and the coarse fraction (PM2.5–10) over time. PM concentrations were measured by reference gravimetric method. Significant changes in PM concentrations over time due to the diversification of pollution sources and other, secondary factors can be observed from the analysis of the measured data. PM samples were subjected to chemical analysis inductively coupled plasma mass spectrometry (ICP-MS) to determine the concentrations of elements (Mg, Al, Ca, Cr, Cu, Fe, Cd, Sb, Ba, Pb, Ni, and Zn). The seasonal variation of elements was evaluated, and the sources of PM2.5, PM1, and PM2.5–10 were estimated using principal component analysis (PCA) and positive matrix factorization (PMF). PM2.5 (maximum concentration of 148.95 µg/m3 over 24 h) and PM1 (maximum concentration of 110.51 µg/m3 over 24 h) showed the highest concentrations during the heating season, together with the elements Cd, Pb, and Zn, which showed a significant presence in these fractions. On the other hand, PM2.5–10 (maximum concentration of 38.17 µg/m3 over 24 h) was significantly related to the elements Cu, Sb, Ba, Ca, Cr, Fe, Mg, and Al. High correlation coefficients (r ≥ 0.8) were found for the elements Mg, Ca, Fe, Al, Cd, Pb, and Zn in the PM1 fraction, Cd, Pb, and Zn in PM2.5, and Ba, Sb, Fe, Cu, Cr, Mg, Al, and Ca in PM2.5–10. Using PMF analysis, three major sources of PM (abrasion from tires and brakes, road dust resuspension/winter salting, and combustion processes) were identified for the PM2.5 and PM1 fractions, as well as for the coarse PM2.5–10 fraction. This study reveals the importance of non-exhaust PM emissions in the urban environment.

scholarly journals Size and time-resolved roadside enrichment of atmospheric particulate pollutants

2011 ◽  
Vol 11 (6) ◽  
pp. 2917-2931 ◽  
Author(s):  
F. Amato ◽  
M. Viana ◽  
A. Richard ◽  
M. Furger ◽  
A. S. H. Prévôt ◽  
...  
Keyword(s):  
Road Traffic ◽  
Heavy Traffic ◽  
Transport Processes ◽  
Traffic Emissions ◽  
Atmospheric Pollutants ◽  
Mineral Matter ◽  
Atmospheric Particulate ◽  
Time Resolved ◽  
Road Traffic Emissions ◽  
Particulate Pollutants

Abstract. Size and time-resolved roadside enrichments of atmospheric particulate pollutants in PM10 were detected and quantified in a Mediterranean urban environment (Barcelona, Spain). Simultaneous data from one urban background (UB), one traffic (T) and one heavy traffic (HT) location were analysed, and roadside PM10 enrichments (RE) in a number of elements arising from vehicular emissions were calculated. Tracers of primary traffic emissions (EC, Fe, Ba, Cu, Sb, Cr, Sn) showed the largest REs (>70%). Other traffic tracers (Zr, Cd) showed lower but still consistent REs (25–40%), similar to those obtained for mineral matter resulting from road dust resuspension (Ca, La, Ce, Ti, Ga, Sr, 30–40%). The sum of primary and secondary organic carbon showed a RE of 41%, with contributions of secondary OC (SOC) to total OC ranging from 46% at the HT site, 63% at the T site, and 78% in the UB. Finally, other trace elements (As, Co, Bi) showed unexpected but consistent roadside enrichments (23% up to 69%), suggesting a link to traffic emissions even though the emission process is unclear. Hourly-resolved PM speciation data proved to be a highly resourceful tool to determine the source origin of atmospheric pollutants in urban environments. At the HT site, up to 62% of fine Mn was attributable to industrial plumes, whereas coarse Mn levels were mainly attributed to traffic. Similarly, even though Zn showed on average no roadside enrichment and thus was classified as industrial, the hourly-resolved data proved that at least 15% of coarse Zn may be attributed to road traffic emissions. In addition, our results indicate that secondary nitrate formation occurs within the city-scale, even in the absence of long atmospheric residence times or long-range atmospheric transport processes. Characteristic tracer ratios of road traffic emissions were identified: Cu/Sb = 6.8–8.0, Cu/Sn = 4.7–5.4 and Sn/Sb = 1.5.

scholarly journals Variability of carbonaceous aerosols in remote, rural, urban and industrial environments in Spain: implications for air quality policy

2013 ◽  
Vol 13 (13) ◽  
pp. 6185-6206 ◽  
Author(s):  
X. Querol ◽  
A. Alastuey ◽  
M. Viana ◽  
T. Moreno ◽  
C. Reche ◽  
...  
Keyword(s):  
Air Quality ◽  
Road Traffic ◽  
Mixing Layer ◽  
Gaseous Emissions ◽  
Carbonaceous Aerosols ◽  
Health Related ◽  
Remote Sites ◽  
Rural Sites ◽  
The Impact ◽  
Urban Sites

Abstract. We interpret here the variability of levels of carbonaceous aerosols based on a 12 yr database from 78 monitoring stations across Spain specially compiled for this article. Data did not evidence any spatial trends of carbonaceous aerosols across the country. Conversely, results show marked differences in average concentrations from the cleanest, most remote sites (around 1 μg m−3 of non-mineral carbon (nmC), mostly made of organic carbon (OC) with very little elemental carbon (EC), around 0.1 μg m−3; OC / EC = 12–15), to the highly polluted major cities (8–10 μg m−3 of nmC; 3–4 μg m−3 of EC; 4–5 μg m−3 of OC; OC / EC = 1–2). Thus, urban (and very specific industrial) pollution was found to markedly increase levels of carbonaceous aerosols in Spain, with much lower impact of biomass burning and of biogenic emissions. Correlations between yearly averaged OC / EC and EC concentrations adjust very well to a potential equation (OC = 3.37 EC0.326, R2 = 0.8). A similar equation is obtained when including average concentrations obtained at other European sites (OC = 3.60EC0.491, R2 = 0.7). A clear seasonal variability in OC and EC concentrations was detected. Both OC and EC concentrations were higher during winter at the traffic and urban sites, but OC increased during the warmer months at the rural sites. Hourly equivalent black carbon (EBC) concentrations at urban sites accurately depict road traffic contributions, varying with distance from road, traffic volume and density, mixing-layer height and wind speed. Weekday urban rush-hour EBC peaks are mimicked by concentrations of primary gaseous emissions from road traffic, whereas a single midday peak is characteristic of remote and rural sites. Decreasing annual trends for carbonaceous aerosols were observed between 1999 and 2011 at a large number of stations, probably reflecting the impact of the EURO4 and EURO5 standards in reducing the diesel PM emissions. This has resulted in some cases in an increasing trend for NO2 / (OC + EC) ratios as these standards have been much less effective for the abatement of NOx exhaust emissions in passenger diesel cars. This study concludes that EC, EBC, and especially nmC and OC + EC are very good candidates for new air quality standards since they cover both emission impact and health-related issues.

scholarly journals EPID-07. ACCESS TO GLIOBLASTOMA CLINICAL TRIALS FOR RURAL PATIENTS IN THE UNITED STATES FROM 2010–2020

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii79-ii79
Author(s):  
Kathryn Nevel ◽  
Samuel Capouch ◽  
Lisa Arnold ◽  
Katherine Peters ◽  
Nimish Mohile ◽  
...  
Keyword(s):  
United States ◽  
Clinical Trials ◽  
Rural Communities ◽  
The United States ◽  
Interventional Treatment ◽  
Phase Ii Trials ◽  
Treatment Trials ◽  
Rural Sites ◽  
Rural Patients ◽  
Urban Sites

Abstract BACKGROUND Patients in rural communities have less access to optimal cancer care and clinical trials. For GBM, access to experimental therapies, and consideration of a clinical trial is embedded in national guidelines. Still, the availability of clinical trials to rural communities, representing 20% of the US population, has not been described. METHODS We queried ClinicalTrials.gov for glioblastoma interventional treatment trials opened between 1/2010 and 1/2020 in the United States. We created a Structured Query Language database and leveraged Google application programming interfaces (API) Places to find name and street addresses for the sites, and Google’s Geocode API to determine the county location. Counties were classified by US Department of Agriculture Rural-Urban Continuum Codes (RUCC 1–3 = urban and RUCC 4–9 = rural). We used z-ratios for rural-urban statistical comparisons. RESULTS We identified 406 interventional treatment trials for GBM at 1491 unique sites. 8.7% of unique sites were in rural settings. Rural sites opened an average of 1.7 trials/site and urban sites 2.8 trials/site from 1/2010–1/2020. Rural sites offered more phase II trials (63% vs 57%, p= 0.03) and fewer phase I trials (22% vs 28%, p= 0.01) than urban sites. Rural locations were more likely to offer federally-sponsored trials (p< 0.002). There were no investigator-initiated or single-institution trials offered at rural locations, and only 1% of industry trials were offered rurally. DISCUSSION Clinical trials for GBM were rarely open in rural areas, and were more dependent on federal funding. Clinical trials are likely difficult to access for rural patients, and this has important implications for the generalizability of research as well as how we engage the field of neuro-oncology and patient advocacy groups in improving patient access to trials. Increasing the number of clinical trials in rural locations may enable more rural patients to access and enroll in GBM studies.

scholarly journals Open Globe Injury related to Road Traffic Accident: a Retrospective Study

2019 ◽  
Author(s):  
Phit Upaphong ◽  
Pongsant Supreeyathitikul ◽  
Janejit Choovuthayakorn
Keyword(s):  
Road Traffic ◽  
Visual Outcome ◽  
Considerable Proportion ◽  
Similar Proportion ◽  
Safety Education ◽  
Open Globe Injury ◽  
Eye Injuries ◽  
Globe Rupture ◽  
Open Globe ◽  
High Prevalence

Abstract BackgroundTo evaluate epidemiology, clinical characteristics and outcomes of patients who sustained road traffic-related open globe injury (OGI)MethodsMedical records of all road traffic-related OGI patients who were admitted to the hospital from January 2006 to December 2016 were retrospectively reviewed. Data including age, gender, vehicle type, initial ocular presentation, and final visual outcome were extracted.ResultsAmong the overall causes of OGI, road traffic-related accidents comprised 92/978 (9%) of cases. Of these, ten (11%) patients acquired bilateral eye injuries and 72 (78%) were male. Nearly half of the injuries (51%) occurred in the 20-39 years old age group and the majority of cases (59%) involved automobile transportation. Globe rupture, 48 (47%) eyes, occurred in a similar proportion of penetration, 46 (45%) eyes. Following treatments, LogMAR visual acuity (VA) significantly improved from a median (interquartile range) of 2.3 (1.9 - 2.3) to 1.7 (0.3 - 3.0), at the final follow-up appointment. Presence of relative afferent pupillary defect and presence of retinal detachment were predictors for poor final visual outcomes.ConclusionsThis study provides information regarding road traffic-related OGI that had a high prevalence in young. The risky transportation mode were motorcycles in teenager and automobiles in young adult. A considerable proportion of impaired final VA might have a significant impact on the socio-economic system. Establishing effective safety education and encouraging regular adherence to road safety behaviors are challenging issues that need more action.

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