scholarly journals The impact of monthly variation of the Pacific-North America (PNA) teleconnection pattern on wintertime surface-layer aerosol concentrations in the United States

2015 ◽  
Vol 15 (22) ◽  
pp. 33209-33251
Author(s):  
J. Feng ◽  
H. Liao ◽  
J. Li
Keyword(s):  
United States ◽  
Surface Layer ◽  
Air Quality ◽  
North America ◽  
Organic Carbon ◽  
Black Carbon ◽  
The United States ◽  
Monthly Variation ◽  
The Pacific ◽  
The Us

Abstract. The Pacific-North America teleconnection (PNA) is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variation of the PNA phase (positive or negative phase) on wintertime surface-layer aerosol concentrations in the US by analyzing observations during 1999–2013 from the Air Quality System of Environmental Protection Agency (EPA-AQS) and the model results for 1986–2006 from the global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). The composite analyses on the EPA-AQS observations over 1999–2003 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon aerosols over the US were higher in the PNA positive phases than in the PNA negative phases by 1.4 μg m−3 (12.7 %), 0.1 μg m−3 (6.4 %), 0.3 μg m−3 (39.1 %), 0.2 μg m−3 (22.8 %), 0.8 μg m−3 (21.3 %), and 0.2 μg m−3 (34.1 %), respectively. The simulated geographical patterns of the differences in concentrations of all aerosol species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation driven by the assimilated meteorological fields, the PNA-induced variation in planetary boundary layer height was found to be the most dominant meteorological factor that influenced the concentrations of PM2.5, sulfate, ammonium, organic carbon, and black carbon, and the PNA-induced variation in temperature was the most important parameter that influenced nitrate aerosol. Results from this work have important implications for understanding and prediction of air quality in the United States.

scholarly journals The impact of monthly variation of the Pacific–North America (PNA) teleconnection pattern on wintertime surface-layer aerosol concentrations in the United States

2016 ◽  
Vol 16 (8) ◽  
pp. 4927-4943 ◽  
Author(s):  
Jin Feng ◽  
Hong Liao ◽  
Jianping Li
Keyword(s):  
United States ◽  
Surface Layer ◽  
Air Quality ◽  
North America ◽  
Organic Carbon ◽  
Black Carbon ◽  
The United States ◽  
The Pacific ◽  
The Us ◽  
The Impact

Abstract. The Pacific–North America teleconnection (PNA) is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variations of the PNA phase (positive or negative phase) on wintertime surface-layer aerosol concentrations in the United States (US) by analyzing observations during 1999–2013 from the Air Quality System of the Environmental Protection Agency (EPA-AQS) and the model results for 1986–2006 from the global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). The composite analyses on the EPA-AQS observations over 1999–2013 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon aerosols over the US were higher in the PNA positive phases (25 % of the winter months examined, and this fraction of months had the highest positive PNA index values) than in the PNA negative phases (25 % of the winter months examined, and this fraction of months had the highest negative PNA index values) by 1.0 µg m−3 (8.7 %), 0.01 µg m−3 (0.5 %), 0.3 µg m−3 (29.1 %), 0.1 µg m−3 (11.9 %), 0.6 µg m−3 (13.5 %), and 0.2 µg m−3 (27.8 %), respectively. The simulated geographical patterns of the differences in concentrations of all aerosol species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation, the pattern correlation coefficients were calculated to show the impacts of PNA-induced variations in meteorological fields on aerosol concentrations. The PNA phase was found (i) to influence sulfate concentrations mainly through changes in planetary boundary layer height (PBLH), precipitation (PR), and temperature; (ii) to influence nitrate concentrations mainly through changes in temperature; and (iii) to influence concentrations of ammonium, organic carbon, and black carbon mainly through changes in PR and PBLH. Results from this work have important implications for the understanding and prediction of air quality in the US.

scholarly journals The Dimensions of the US-China Trade War

2020 ◽  
Vol 3 (1) ◽  
pp. 47-55
Author(s):  
Mohamad Zreik
Keyword(s):  
United States ◽  
Indian Ocean ◽  
Free Trade ◽  
The United States ◽  
Bilateral Agreements ◽  
China Trade ◽  
The Pacific ◽  
The Us ◽  
The Indian Ocean ◽  
Trade War

AbstractThe Chinese Ministry of Commerce issued a statement Friday morning, July 6, 2018, confirming the outbreak of a trade war between the United States and China. The statement came after the United States imposed tariffs on many Chinese goods, in violation of international and bilateral agreements, and the destruction of the concept of free trade which the United States calls for following it. It is a war of opposite directions, especially the contradiction between the new Trump policy and the Chinese approach. The proof is what US Defense Secretary James Matisse announced in Singapore in early June 2018 of “the full strategy of the new United States, in the Indian Ocean and the Pacific,” where China was the “sole enemy of the United States” in China’s geostrategic region. Intentions have become publicized, and trade war between the two economic giants is turning into a reality. This paper will give an overview of the US-China scenario of trade war, then a focused analysis on the Trump’s administration economic decision regarding China, and the consequences of this decision.

scholarly journals Bicycling, Birding and #BLM across America in a Summer of Chaos

2020 ◽  
Vol 4 ◽  
Author(s):  
Scott Edwards
Keyword(s):  
United States ◽  
Social Media ◽  
National Level ◽  
Political Stability ◽  
The United States ◽  
Local Communities ◽  
Rural America ◽  
The Pacific ◽  
The Us ◽  
White Violence

From 6 June to 20 August, 2020, I undertook a 76-day, ~3800 mile bicycle trip across the United States from the Atlantic to the Pacific oceans. In this talk I will share with you some of the amazing people, landscapes and birds I encountered, mostly in rural towns and along blue highways. The gradually changing birdscape, both in sight and sound, underscored the sensitive ecological gradients to which birds respond, as well as the ability of some species to thrive in agricultural monocultures. Rivers large and small regularly benchmarked my progress, as well as the western journey of Lewis & Clark over 200 years ago. The recent incidents in the US involving African Americans as targets of white violence inexorably caused me to festoon my bicycle with #BlackLivesMatter (#BLM) signs and share my experiences on social media. I encountered a variety of reactions, often positive and occasionally sharply negative, in a sea of generosity and extraordinary kindness as I wheeled my way through towns on the brink of collapse, vast private ranches and the occasional city. Rural America exhibits an abundance of loyalty and empathy for local communities, yet it is sometimes hard for Americans – myself included – to empathize with people they have never met in person. Two imperatives I took away, with ramifications for both biodiversity and political stability, were the need to somehow bring divergent communities together and to encourage empathy at the national level, among communities that otherwise experience each other only on TV.

Burden-sharing: the US, Australia and New Zealand alliances in the Pacific islands

2021 ◽  
Author(s):  
Joanne Wallis ◽  
Anna Powles
Keyword(s):  
United States ◽  
New Zealand ◽  
Pacific Islands ◽  
Critical Role ◽  
The United States ◽  
Burden Sharing ◽  
Military Capability ◽  
The Pacific ◽  
Security Challenges ◽  
The Us

Abstract One of President Joseph Biden's foreign policy priorities is to ‘renew’ and ‘strengthen’ the United States' alliances, as they were perceived to have been ‘undermined’ during the Trump administration, which regularly expressed concern that allies were free-riding on the United States' military capability. Yet the broad range of threats states face in the contemporary context suggests that security assistance from allies no longer only—or even primarily—comes in the form of military capability. We consider whether there is a need to rethink understandings of how alliance relationships are managed, particularly how the goals—or strategic burdens—of alliances are understood, how allies contribute to those burdens, and how influence is exercised within alliances. We do this by analysing how the United States–Australia and Australia–New Zealand alliances operate in the Pacific islands. Our focus on the Pacific islands reflects the United States' perception that the region plays a ‘critical’ role in helping to ‘preserve a free and open Indo-Pacific region’. We conclude that these understandings need to be rethought, particularly in the Pacific islands, where meeting non-traditional security challenges such as economic, social and environmental issues, is important to advancing the United States, Australia and New Zealand's shared strategic goal of remaining the region's primary security partners and ensuring that no power hostile to their interests establishes a strategic foothold.

scholarly journals The contribution of marine organics to the air quality of the western United States

2010 ◽  
Vol 10 (15) ◽  
pp. 7415-7423 ◽  
Author(s):  
B. Gantt ◽  
N. Meskhidze ◽  
A. G. Carlton
Keyword(s):  
United States ◽  
Air Quality ◽  
San Francisco ◽  
Atmospheric Chemistry ◽  
Environmental Protection Agency ◽  
Regional Scale ◽  
The United States ◽  
Coastal Areas ◽  
Western United States ◽  
The Us

Abstract. The contribution of marine organic emissions to the air quality in coastal areas of the western United States is studied using the latest version of the US Environmental Protection Agency (EPA) regional-scale Community Multiscale Air Quality (CMAQv4.7) modeling system. Emissions of marine isoprene, monoterpenes, and primary organic matter (POM) from the ocean are implemented into the model to provide a comprehensive view of the connection between ocean biology and atmospheric chemistry and air pollution. Model simulations show that marine organics can increase the concentration of PM2.5 by 0.1–0.3 μg m−3 (up to 5%) in some coastal cities such as San Francisco, CA. This increase in the PM2.5 concentration is primarily attributed to the POM emissions, with small contributions from the marine isoprene and monoterpenes. When marine organic emissions are included, organic carbon (OC) concentrations over the remote ocean are increased by up to 50% (25% in coastal areas), values consistent with recent observational findings. This study is the first to quantify the air quality impacts from marine POM and monoterpenes for the United States, and it highlights the need for inclusion of marine organic emissions in air quality models.

The intelligence of six-year-olds in Hong Kong

1989 ◽  
Vol 21 (4) ◽  
pp. 461-464 ◽  
Author(s):  
Jimmy Chan ◽  
Richard Lynn
Keyword(s):  
United States ◽  
Hong Kong ◽  
Ethnic Minorities ◽  
The United States ◽  
Chinese Children ◽  
Pacific Basin ◽  
The Pacific ◽  
The Us ◽  
The Mean ◽  
The Uk

SummaryEvidence has accumulated to suggest that the mean IQs of Orientals in the United States and in the countries of the Pacific Basin are higher than those of Whites (Caucasoids) in the United States and Britain. This paper presents evidence from IQ tests on 4858 6-year-old Chinese children in Hong Kong. On the Coloured Progressive Matrices these children obtained a mean IQ of 116. Samples from Australia, Czechoslovakia, Germany, Romania, the UK and the US obtain IQs in the range 95–102. It is suggested that these results pose difficulties for the environmentalist explanations commonly advanced to explain the low mean IQs obtained by some ethnic minorities in the United States.

scholarly journals A Missed Partnership: Russia and the US at the Pacific

2019 ◽  
Vol 12 (1) ◽  
pp. 159-184
Author(s):  
D. V. Suslov
Keyword(s):  
United States ◽  
The United States ◽  
Asia Pacific ◽  
Asia Pacific Region ◽  
The Pacific ◽  
The Us ◽  
The Face ◽  
Soviet Space ◽  
Favorable Conditions ◽  
Post Soviet Space

Both Russia and the United States consider the Asia-Pacific as the center of the world economy and politics and assume the active presence in the region crucial for their security and economic development. They did not have such sharp contradictions there as in Europe or in the post-Soviet space. Moreover, some of their interests in the Asia-Pacific Region coincide – such as preventing Chinese hegemony. In this regard, the Russian-American dialogue and cooperation in the Asia-Pacific could be an important pillar of the positive agenda of their relations and a factor in their sustainability. Due to foreign policy inertia, the inflexibility of the agenda of Russian-American relations and the inability of the parties to go beyond the usual pattern, such a dialogue has not even begun. Both sides demonstrated strategic myopia. This weakened the resilience of US-Russian relations in the face of new challenges and accelerated their deterioration and disruption to a new confrontation. The Asia-Pacific has become another theater of the US-Russian systemic confrontation. However, it is in the interest of bothRussia and the United States to separate relations in this region from their general confrontation. This will create favorable conditions for Russia to build a balanced partnership system in the Asia-Pacific, which is necessary to consolidate its role as an independent global great power. In addition, the Russian-American dialogue on the Asia-Pacific, or at least the weakening of their confrontation in this region, will reduce its polarization and prevent tensions between the US and its Asian allies and partners.

scholarly journals Music Therapy in the United States

2001 ◽  
Vol 1 (2) ◽  
Author(s):  
Michele Forinash
Keyword(s):  
United States ◽  
North America ◽  
Music Therapy ◽  
The United States ◽  
The Us

As I have just come on board as the editor for North America for this particular issue I will address music therapy in the US. Future issues of the journal will focus on music therapy in other parts of North America.

scholarly journals Development and application of a United States-wide correction for PM<sub>2.5</sub> data collected with the PurpleAir sensor

2021 ◽  
Vol 14 (6) ◽  
pp. 4617-4637
Author(s):  
Karoline K. Barkjohn ◽  
Brett Gantt ◽  
Andrea L. Clements
Keyword(s):  
United States ◽  
Air Quality ◽  
Reference Method ◽  
Ambient Air ◽  
The United States ◽  
Global Network ◽  
Raw Data ◽  
The Us ◽  
State And Local ◽  
Multiplicative Models

Abstract. PurpleAir sensors, which measure particulate matter (PM), are widely used by individuals, community groups, and other organizations including state and local air monitoring agencies. PurpleAir sensors comprise a massive global network of more than 10 000 sensors. Previous performance evaluations have typically studied a limited number of PurpleAir sensors in small geographic areas or laboratory environments. While useful for determining sensor behavior and data normalization for these geographic areas, little work has been done to understand the broad applicability of these results outside these regions and conditions. Here, PurpleAir sensors operated by air quality monitoring agencies are evaluated in comparison to collocated ambient air quality regulatory instruments. In total, almost 12 000 24 h averaged PM2.5 measurements from collocated PurpleAir sensors and Federal Reference Method (FRM) or Federal Equivalent Method (FEM) PM2.5 measurements were collected across diverse regions of the United States (US), including 16 states. Consistent with previous evaluations, under typical ambient and smoke-impacted conditions, the raw data from PurpleAir sensors overestimate PM2.5 concentrations by about 40 % in most parts of the US. A simple linear regression reduces much of this bias across most US regions, but adding a relative humidity term further reduces the bias and improves consistency in the biases between different regions. More complex multiplicative models did not substantially improve results when tested on an independent dataset. The final PurpleAir correction reduces the root mean square error (RMSE) of the raw data from 8 to 3 µg m−3, with an average FRM or FEM concentration of 9 µg m−3. This correction equation, along with proposed data cleaning criteria, has been applied to PurpleAir PM2.5 measurements across the US on the AirNow Fire and Smoke Map (https://fire.airnow.gov/, last access: 14 May 2021) and has the potential to be successfully used in other air quality and public health applications.

scholarly journals How emissions, climate, and land use change will impact mid-century air quality over the United States: a focus on effects at National Parks

2014 ◽  
Vol 14 (19) ◽  
pp. 26495-26543 ◽  
Author(s):  
M. Val Martin ◽  
C. L. Heald ◽  
J.-F. Lamarque ◽  
S. Tilmes ◽  
L. K. Emmons ◽  
...  
Keyword(s):  
United States ◽  
Land Use ◽  
Air Quality ◽  
National Parks ◽  
Land Use Changes ◽  
The United States ◽  
Western Us ◽  
The Us ◽  
Us Epa ◽  
Surface O3

Abstract. We use a global coupled chemistry-climate-land model (CESM) to assess the integrated effect of climate, emissions and land use changes on annual surface O3 and PM2.5 on the United States with a focus on National Parks (NPs) and wilderness areas, using the RCP4.5 and RCP8.5 projections. We show that, when stringent domestic emission controls are applied, air quality is predicted to improve across the US, except surface O3 over the western and central US under RCP8.5 conditions, where rising background ozone counteracts domestic emissions reductions. Under the RCP4.5, surface O3 is substantially reduced (about 5 ppb), with daily maximum 8 h averages below the primary US EPA NAAQS of 75 ppb (and even 65 ppb) in all the NPs. PM2.5 is significantly reduced in both scenarios (4 μg m−3; ~50%), with levels below the annual US EPA NAAQS of 12 μg m−3 across all the NPs; visibility is also improved (10–15 deciviews; >75 km in visibility range), although some parks over the western US (40–74% of total sites in the US) may not reach the 2050 target to restore visibility to natural conditions by 2064. We estimate that climate-driven increases in fire activity may dominate summertime PM2.5 over the western US, potentially offsetting the large PM2.5 reductions from domestic emission controls, and keeping visibility at present-day levels in many parks. Our study suggests that air quality in 2050 will be primarily controlled by anthropogenic emission patterns. However, climate and land use changes alone may lead to a substantial increase in surface O3 (2–3 ppb) with important consequences for O3 air quality and ecosystem degradation at the US NPs. Our study illustrates the need to consider the effects of changes in climate, vegetation, and fires in future air quality management and planning and emission policy making.

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