scholarly journals Intercontinental transport of pollution and dust aerosols: implications for regional air quality

2007 ◽  
Vol 7 (21) ◽  
pp. 5501-5517 ◽  
Author(s):  
Mian Chin ◽  
T. Diehl ◽  
P. Ginoux ◽  
W. Malm
Keyword(s):  
North America ◽  
Ammonium Sulfate ◽  
The United States ◽  
Annual Average ◽  
Dust Aerosols ◽  
African Dust ◽  
The North ◽  
Western Asia ◽  
The Impact ◽  
The U.S

Abstract. We use the global model GOCART to examine the impact of pollution and dust aerosols emitted from their major sources on surface fine particulate matter concentrations at regional and hemispheric scales. Focusing on the North America region in 2001, we use measurements from the IMPROVE network in the United States to evaluate the model-simulated surface concentrations of the "reconstructed fine mass" (RCFM) and its components of ammonium sulfate, black carbon (BC), organic matter (OM), and fine mode dust. We then quantify the RCFM budget in terms of the RCFM chemical composition, source type, and region of origin to find that in the eastern U.S., ammonium sulfate is the dominant RCFM component (~60%) whereas in the western U.S., dust and OM are just as important as sulfate but have considerable seasonal variations, especially in the NW. On an annual average, pollution aerosol (defined as aerosols from fuel combustion for industrial and transportation uses) from North America accounts for 65–70% of the surface RCFM in the eastern U.S. and for a lower proportion of 30–40% in the western U.S.; by contrast, pollution from outside of North America contributes to just 2–6% (~0.2 μg m−3) of the total RCFM over the U.S. In comparison, long-range transport of dust brings 3 to 4 times more fine particles than the transport of pollution to the U.S. (0.5–0.8 μg m−3 on an annual average) with a maximum influence in spring and over the NW. Of the major pollution regions, Europe has the largest potential to affect the surface aerosol concentrations in other continents due to its shorter distance from receptor continents and its larger fraction of sulfate-producing precursor gas in the outflow. With the IPCC emission scenario for the year 2000, we find that European emissions increase levels of ammonium sulfate by 1–5 μg m−3 over the surface of northern Africa and western Asia, and its contribution to eastern Asia (≥0.2 μg m−3) is twice as much as the Asian contribution to North America. Asia and North America pollution emissions exert strong impacts on their neighboring oceans, but their influences over other continents are relatively small (≤10%) due to long traveling distances across the oceans and efficient removal during transport. Among the major dust source regions, Asia displays a significant influence over large areas in the northern hemisphere except over the North Atlantic and the tropics, where African dust dominates. We also notice that the African dust and European pollution can travel eastward through a pathway spanning across Asia and North Pacific to western North America; such a pathway is difficult to detect because these aerosols usually merge and travel together with Asian dust and pollution labeled as "Asian outflow".

scholarly journals Intercontinental transport of pollution and dust aerosols: implications for regional air quality

2007 ◽  
Vol 7 (3) ◽  
pp. 9013-9051 ◽  
Author(s):  
◽  
T. Diehl ◽  
P. Ginoux ◽  
W. Malm
Keyword(s):  
North America ◽  
Ammonium Sulfate ◽  
The United States ◽  
Asian Dust ◽  
Annual Average ◽  
Dust Aerosols ◽  
African Dust ◽  
The North ◽  
The Impact ◽  
The U.S

Abstract. We use the global model GOCART to examine the impact of pollution and dust aerosols emitted from their major sources on surface fine particulate matter concentrations at regional and hemispheric scales. Focusing on the North America region in 2001, we use measurements from the IMPROVE network in the United States to evaluate the model-simulated surface concentrations of the "reconstructed fine mass" (RCFM) and its components of ammonium sulfate, black carbon (BC), organic matter (OM), and fine mode dust. We then quantify the RCFM budget in terms of the RCFM composition, type, and origin to find that in the eastern U.S., ammonium sulfate is the dominant RCFM component (~60%) whereas in the western U.S., dust and OM are just as important as sulfate but have considerable seasonal variations, especially in the NW. On an annual average, North America regional pollution accounts for nearly 30–40% of the surface RCFM in the western U.S., and for a much higher proportion of 65–70% in the eastern U.S. By contrast, pollution from outside of North America contributes to just 2–6% (~0.2 μg m−3) of the total RCFM over the U.S. on an annual average. In comparison, long-range transport of dust is more efficient than that of pollution, which brings 3 to 4 times more fine particles to the U.S. (0.5–0.8 μg m−3 on an annual average) with a maximum influence in spring and over the NW. Of the major pollution regions, Europe has the largest potential to affect the surface aerosol concentrations in other continents due to its shorter distance from receptor continents and its larger fraction of sulfate-producing precursor gas in the outflow. With the IPCC emission scenario for the year 2000, we find that European emissions increase levels of ammonium sulfate by 1–5 μg m−3 over the surface of northern Africa and western Asia, and its contribution to eastern Asia (≥0.2 μg m−3) is twice as much as the Asian contribution to North America. Asia and North America pollution emissions exert strong impacts on their neighboring oceans, but their influences on other continents are relatively small (≤10%) due to the long traveling distance across the oceans and efficient removal during transport. Among the major dust source regions, Asia displays a significant influence over large areas in the Northern Hemisphere except over the North Atlantic and the tropics, where African dust dominates. The trans-Pacific transport of Asian dust is much more efficient than that of Asian pollution because of the higher elevation and lower removal rate of dust. We notice that the African dust can travel eastward through a pathway spanning across Asia and North Pacific to settle down over the surface of western North America. African dust transported through such a pathway is difficult to detect because it usually merges and travels together with the Asian dust.

scholarly journals The North American Lightning Detection Network (NALDN)—Analysis of Flash Data: 2001–09

2011 ◽  
Vol 139 (5) ◽  
pp. 1305-1322 ◽  
Author(s):  
Richard E. Orville ◽  
Gary R. Huffines ◽  
William R. Burrows ◽  
Kenneth L. Cummins
Keyword(s):  
United States ◽  
North America ◽  
North American ◽  
The United States ◽  
The North ◽  
Lightning Detection ◽  
Geographical Regions ◽  
Positive Peak ◽  
The U.S ◽  
Cg Lightning

Cloud-to-ground (CG) lightning data have been analyzed for the years 2001–09 for North America, which includes Alaska, Canada, and the lower 48 U.S. states. Flashes recorded within the North American Lightning Detection Network (NALDN) are examined. No corrections for detection efficiency variability are made over the 9 yr of the dataset or over the large geographical area comprising North America. There were network changes in the NALDN during the 9 yr, but these changes have not been corrected for nor have the recorded data been altered in any way with the exception that all positive lightning reports with peak currents less than 15 kA have been deleted. Thus, the reader should be aware that secular changes are not just climatological in nature. All data were analyzed with a spatial resolution of 20 km. The analyses presented in this work provide a synoptic view of the interannual variability of lightning observations in North America, including the impacts of physical changes in the network during the 9 yr of study. These data complement and extend previous analyses that evaluate the U.S. NLDN during periods of upgrade. The total (negative and positive) flashes for ground flash density, the percentage of positive lightning, and the positive flash density have been analyzed. Furthermore, the negative and positive first stroke peak currents and the flash multiplicity have been examined. The highest flash densities in Canada are along the U.S.–Canadian border (1–2 flashes per square kilometer) and in the United States along the Gulf of Mexico coast from Texas through Florida (exceeding 14 flashes per square kilometer in Florida). The Gulf Stream is “outlined” by higher flash densities off the east coast of the United States. Maximum annual positive flash densities in Canada range primarily from 0.01 to 0.3 flashes per square kilometer, and in the United States to over 0.5 flashes per square kilometer in the Midwest and in the states of Louisiana and Mississippi. The annual percentage of positive lightning to ground varies from less than 2% over Florida to values exceeding 25% off the West Coast, Alaska, and the Yukon. A localized maximum in the percentage of positive lightning in the NALDN occurs in Manitoba and western Ontario, just north of North Dakota and Minnesota. When averaged over North America, first stroke negative median peak currents range from 19.8 kA in 2001 to 16.0 kA in 2009 and for all years, average 16.1 kA. First stroke positive median peak currents range from a high of 29.0 kA in 2008 and 2009 to a low of 23.3 kA in 2003 with a median of 25.7 kA for all years. There is a relatively sharp transition from low to high median negative peak currents along the Gulf and Atlantic coasts of the United States. No sharp transitions are observed for the median positive peak currents. Relatively lower positive peak currents occur throughout the southeastern United States. The highest values of mean negative multiplicity exceed 3.0 strokes per flash in the NALDN with some variation over the 9 yr. Lower values of mean negative multiplicity occur in the western United States. Positive flash mean multiplicity is slightly higher than 1.1, with the highest values of 1.7 observed in the southwestern states. As has been noted in prior research, CG lightning has significant variations from storm to storm as well as between geographical regions and/or seasons and, consequently, a single distribution for any lightning parameter, such as multiplicity or peak current, may not be sufficient to represent or describe the parameter.

scholarly journals The Impact of NAFTA on the United States

2001 ◽  
Vol 15 (1) ◽  
pp. 125-144 ◽  
Author(s):  
Mary E Burfisher ◽  
Sherman Robinson ◽  
Karen Thierfelder
Keyword(s):  
Free Trade Agreement ◽  
Trade Agreement ◽  
Trade Diversion ◽  
The United States ◽  
Trade Creation ◽  
Policy Debate ◽  
Trade Data ◽  
The North ◽  
The Impact ◽  
The U.S

We describe the main economic arguments posed for and against the North American Free Trade Agreement (NAFTA) during the U.S. policy debate. To evaluate these arguments, we analyze recent trade data and survey post-NAFTA studies. We find that both the U.S. and Mexico benefit from NAFTA, with much larger relative benefits for Mexico. NAFTA also has had little effect on the U.S. labor market. These results confirm the consensus opinion of economists at the time of the debate. Finally, studies find that trade creation greatly exceeds trade diversion in the region under NAFTA, especially in intermediate goods.

scholarly journals Prospects for the North America’ shale hydrocarbons development

2014 ◽  
pp. 97-105
Author(s):  
T. V. Polyakova
Keyword(s):  
North America ◽  
Oil And Gas ◽  
Gas Production ◽  
Oil And Gas Production ◽  
Political Issues ◽  
Political Consequences ◽  
The North ◽  
Oil And Gas Resources ◽  
The Impact ◽  
The U.S

An entire generation of American politicians were concerned about the growing U.S. dependence on imported oil and natural gas. However, in the last few years the situation has changed dramatically: there was started the development of not only the resources of shale gas, but shale oil. As a result in political and economic circles they began to talk about it as the most significant breakthrough in the energy resources development since the oil boom in Texas in the late 1920s. How large are these resources? What problems have to be overcome if the available potential will be realized? How will this problems affect the U.S. energy policy? Concerns about the adequacy of regulation, in particular the environmental issues associated with the non-conventional hydrocarbons production, have led to the internal public debate on the impact of unconventional oil and gas resources mining boom. One thing is clear: significant amounts of additional oil and gas supplies in the U.S. will have far-reaching political consequences for the world. The article presents the different points of view on the prospects for oil and gas production in North America, as well as on the political issues related to it.

Pentecostalism and African diaspora : a case study of the Redeemed Christian Church of God (RCCG), in North America

2020 ◽  
Vol 1 (2) ◽  
pp. 77-92
Author(s):  
Rotimi Williams Omotoye
Keyword(s):  
United States ◽  
North America ◽  
United States Of America ◽  
The United States ◽  
Church Of God ◽  
Sources Of Information ◽  
Christian Church ◽  
Secondary Sources ◽  
The Impact ◽  
The Church

Pentecostalism as a new wave of Christianity became more pronounced in 1970's and beyond in Nigeria. Since then scholars of Religion, History, Sociology and Political Science have shown keen interest in the study of the Churches known as Pentecostals because of the impact they have made on the society. The Redeemed Christian Church of God (RCCG) was established by Pastor Josiah Akindayomi in Lagos,Nigeria in 1952. After his demise, he was succeeded by Pastor Adeboye Adejare Enock. The problem of study of this research was an examination of the expansion of the Redeemed Christian Church of God to North America, Caribbean and Canada. The missionary activities of the church could be regarded as a reversed mission in the propagation of Christianity by Africans in the Diaspora. The methodology adopted was historical. The primary and secondary sources of information were also germane in the research. The findings of the research indicated that the Redeemed Christian Church of God was founded in North America by Immigrants from Nigeria. Pastor Adeboye Enock Adejare had much influence on the Church within and outside the country because of his charisma. The Church has become a place of refuge for many immigrants. They are also contributing to the economy of the United States of America. However, the members of the Church were faced with some challenges, such as security scrutiny by the security agencies. In conclusion, the RCCGNA was a denomination that had been accepted and embraced by Nigerians and African immigrants in the United States of America.

THE INFLUENCE OF SCOTTISH ACCOUNTANTS IN THE UNITED STATES: THE EARLY CASE OF THE SOCIETY OF ACCOUNTANTS IN EDINBURGH

1997 ◽  
Vol 24 (1) ◽  
pp. 117-141 ◽  
Author(s):  
T. A. LEE
Keyword(s):  
United States ◽  
General Theory ◽  
Research Program ◽  
The United States ◽  
The World ◽  
Early Case ◽  
The Impact ◽  
Chartered Accountants ◽  
The U.S

This study represents part of a long-term research program to investigate the influence of U.K. accountants on the development of professional accountancy in other parts of the world. It examines the impact of a small group of Scottish chartered accountants who emigrated to the U.S. in the late 1800s and early 1900s. Set against a general theory of emigration, the study's main results reveal the significant involvement of this group in the founding and development of U.S. accountancy. The influence is predominantly with respect to public accountancy and its main institutional organizations. Several of the individuals achieved considerable eminence in U.S. public accountancy.

scholarly journals Progress in Diagnosing Primary Ciliary Dyskinesia: The North American Perspective

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1278
Author(s):  
Michael Glenn O’Connor ◽  
Amjad Horani ◽  
Adam J. Shapiro
Keyword(s):  
Genetic Testing ◽  
North America ◽  
North American ◽  
Primary Ciliary Dyskinesia ◽  
Clinical Phenotype ◽  
The United States ◽  
Diagnostic Process ◽  
The North ◽  
Diagnostic Guideline ◽  
Ciliary Dyskinesia

Primary Ciliary Dyskinesia (PCD) is a rare, under-recognized disease that affects respiratory ciliary function, resulting in chronic oto-sino-pulmonary disease. The PCD clinical phenotype overlaps with other common respiratory conditions and no single diagnostic test detects all forms of PCD. In 2018, PCD experts collaborated with the American Thoracic Society (ATS) to create a clinical diagnostic guideline for patients across North America, specifically considering the local resources and limitations for PCD diagnosis in the United States and Canada. Nasal nitric oxide (nNO) testing is recommended for first-line testing in patients ≥5 years old with a compatible clinical phenotype; however, all low nNO values require confirmation with genetic testing or ciliary electron micrograph (EM) analysis. Furthermore, these guidelines recognize that not all North American patients have access to nNO testing and isolated genetic testing is appropriate in cases with strong clinical PCD phenotypes. For unresolved diagnostic cases, referral to a PCD Foundation accredited center is recommended. The purpose of this narrative review is to provide insight on the North American PCD diagnostic process, to enhance the understanding of and adherence to current guidelines, and to promote collaboration with diagnostic pathways used outside of North America.

scholarly journals How Representative Are Snowball Samples? Using the Ethnosurvey to Study Guatemala-U.S. Migration

2016 ◽  
Vol 666 (1) ◽  
pp. 64-76
Author(s):  
David P. Lindstrom
Keyword(s):  
Rhode Island ◽  
Composite Index ◽  
The United States ◽  
Mexican Migration ◽  
Background Characteristics ◽  
Household Location ◽  
Sample Weighting ◽  
Migrant Integration ◽  
The Impact ◽  
The U.S

This analysis draws on binational data from an ethnosurvey conducted in Guatemala and in the United States in Providence, Rhode Island, to develop a refinement of the weighting scheme that the Mexican Migration Project (MMP) uses. The alternative weighting procedure distinguishes between temporary and settled migrants by using a question on household location in the Guatemala questionnaire that is not used in the MMP. Demographic characteristics and integration experiences of the most recent U.S. trip are used to assess the composition and representativeness of the U.S. sample. Using a composite index of migrant integration to compare the impact of alternative U.S. sample weights on point estimates, I find that although the U.S. sample is broadly representative across a range of background characteristics, the MMP sample weighting procedure biases estimates of migrant integration downward.

scholarly journals A Risk-Based Strategy for Evaluating Mitigation Options for Process-Formed Compounds in Food

2016 ◽  
Vol 35 (3) ◽  
pp. 358-370 ◽  
Author(s):  
Paul Hanlon ◽  
Gregory P. Brorby ◽  
Mansi Krishan
Keyword(s):  
North America ◽  
Decision Tree ◽  
Scientific Community ◽  
Life Sciences ◽  
Technical Committee ◽  
Global Approach ◽  
Chemical Safety ◽  
The Public ◽  
The North ◽  
The Impact

Processing (eg, cooking, grinding, drying) has changed the composition of food throughout the course of human history; however, awareness of process-formed compounds, and the potential need to mitigate exposure to those compounds, is a relatively recent phenomenon. In May 2015, the North American Branch of the International Life Sciences Institute (ILSI North America) Technical Committee on Food and Chemical Safety held a workshop on the risk-based process for mitigation of process-formed compounds. This workshop aimed to gain alignment from academia, government, and industry on a risk-based process for proactively assessing the need for and benefit of mitigation of process-formed compounds, including criteria to objectively assess the impact of mitigation as well as research needed to support this process. Workshop participants provided real-time feedback on a draft framework in the form of a decision tree developed by the ILSI North America Technical Committee on Food and Chemical Safety to a panel of experts, and they discussed the importance of communicating the value of such a process to the larger scientific community and, ultimately, the public. The outcome of the workshop was a decision tree that can be used by the scientific community and could form the basis of a global approach to assessing the risks associated with mitigation of process-formed compounds.

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