scholarly journals Long-range transport of sulfur in the western United States. [Projections for 1985 and 1990]

1979 ◽  
Author(s):  
W. F. Sandusky ◽  
W. J. Eadie ◽  
D. R. Drewes
Keyword(s):  
United States ◽  
Long Range ◽  
Western United States ◽  
Long Range Transport ◽  
Range Transport

scholarly journals Inconsistent decadal variations between surface and free tropospheric nitrogen oxides over United States

2017 ◽  
Author(s):  
Zhe Jiang ◽  
Helen Worden ◽  
John R. Worden ◽  
Daven K. Henze ◽  
Dylan B. A. Jones ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Nitrogen Oxides ◽  
Climate Variability ◽  
Long Range ◽  
North American ◽  
Long Range Transport ◽  
Substantial Impact ◽  
Decadal Scale ◽  
Range Transport

Abstract. Decreases in surface emissions of nitrogen oxides (NOx = NO + NO2) in North America have led to substantial improvements in air-quality over the last several decades. Here we show that satellite observations of tropospheric nitrogen dioxide (NO2) columns over the contiguous United States (US) do not decrease after about 2009, while surface NO2 concentrations continue to decline through to the present. This divergence, if it continues, could have a substantial impact on surface air quality due to mixing of free-tropospheric air into the boundary layer. Our results show only limited contributions from local effects such as fossil fuel emissions, lightning, or instrument artifacts, but we do find a possible relationship of NO2 changes to decadal climate variability. Our analysis demonstrates that the intensity of transpacific transport is stronger in El Niño years and weaker in La Niña years, and consequently, that decadal-scale climate variability impacts the contribution of Asian emissions on North American atmospheric composition. Because of the short lifetime, it is usually believed that the direct contribution of long-range transport to tropospheric NOx distribution is limited. If our hypothesis about transported Asian emissions is correct, then this observed divergence between satellite and surface NOx could indicate mechanisms that allow for either NOx or its reservoir species to have a larger than expected effect on North American tropospheric composition. These results therefore suggest more aircraft and satellite studies to determine the possible missing processes in our understanding of the long-range transport of tropospheric NOx.

scholarly journals Long-range transport of North African dust to the eastern United States

1997 ◽  
Vol 102 (D10) ◽  
pp. 11225-11238 ◽  
Author(s):  
Kevin D. Perry ◽  
Thomas A. Cahill ◽  
Robert A. Eldred ◽  
Dabrina D. Dutcher ◽  
Thomas E. Gill
Keyword(s):  
United States ◽  
Long Range ◽  
Long Range Transport ◽  
Eastern United States ◽  
North African ◽  
African Dust ◽  
Range Transport

Air Quality Forecast Verification Using Satellite Data

2008 ◽  
Vol 47 (2) ◽  
pp. 425-442 ◽  
Author(s):  
S. Kondragunta ◽  
P. Lee ◽  
J. McQueen ◽  
C. Kittaka ◽  
A. I. Prados ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Long Range ◽  
Regional Scale ◽  
The United States ◽  
Long Range Transport ◽  
Forecast Performance ◽  
Air Quality Forecast ◽  
Time Period ◽  
Range Transport

Abstract NOAA’s operational geostationary satellite retrievals of aerosol optical depths (AODs) were used to verify National Weather Service developmental (research mode) particulate matter (PM2.5) predictions tested during the summer 2004 International Consortium for Atmospheric Research on Transport and Transformation/New England Air Quality Study (ICARTT/NEAQS) field campaign. The forecast period included long-range transport of smoke from fires burning in Canada and Alaska and a regional-scale sulfate event over the Gulf of Mexico and the eastern United States. Over the 30-day time period for which daytime hourly forecasts were compared with observations, the categorical (exceedance defined as AOD > 0.55) forecast accuracy was between 0% and 20%. Hourly normalized mean bias (forecasts − observations) ranged between −50% and +50% with forecasts being positively biased when observed AODs were small and negatively biased when observed AODs were high. Normalized mean errors are between 50% and 100% with the errors on the lower end during the 18–22 July 2004 time period when a regional-scale sulfate event occurred. Spatially, the errors are small over the regions where sulfate plumes were present. The correlation coefficient also showed similar features (spatially and temporally) with a peak value of ∼0.6 during the 18–22 July 2004 time period. The dominance of long-range transport of smoke into the United States during the summer of 2004, neglected in the model predictions, skewed the model forecast performance. Enhanced accuracy and reduced normalized mean errors during the time period when a sulfate event prevailed show that the forecast system has skill in predicting PM2.5 associated with urban/industrial pollution events.

An investigation of long-range transport of ozone across the midwestern and eastern united states

1977 ◽  
Vol 11 (9) ◽  
pp. 797-802 ◽  
Author(s):  
George T. Wolff ◽  
Paul J. Lioy ◽  
Gregory D. Wight ◽  
Ronald E. Meyers ◽  
Richard T. Cederwall
Keyword(s):  
United States ◽  
Long Range ◽  
Long Range Transport ◽  
Eastern United States ◽  
Range Transport

scholarly journals Investigating sources of gaseous oxidized mercury in dry deposition at three sites across Florida, USA

2012 ◽  
Vol 12 (19) ◽  
pp. 9201-9219 ◽  
Author(s):  
M. Sexauer Gustin ◽  
P. S. Weiss-Penzias ◽  
C. Peterson
Keyword(s):  
United States ◽  
Long Range ◽  
Dry Deposition ◽  
Passive Sampling ◽  
Point Sources ◽  
Long Range Transport ◽  
Range Transport ◽  
Potential Sources ◽  
Sampling Systems ◽  
Surrogate Surfaces

Abstract. During 2009–2010, the State of Florida established a series of air quality monitoring stations to collect data for development of a statewide total maximum daily load (TMDL) for mercury (Hg). At three of these sites, located near Ft. Lauderdale (DVE), Pensacola (OLF), and Tampa Bay (TPA), passive samplers for the measurement of air Hg concentrations and surrogate surfaces for measurement of Hg dry deposition were deployed. While it is known that Hg in wet deposition in Florida is high compared to the rest of the United States, there is little information on Hg dry deposition. The objectives of the work were to: (1) investigate the utility of passive sampling systems for Hg in an area with low and consistent air concentrations as measured by the Tekran® mercury measurement system, (2) estimate dry deposition of gaseous oxidized Hg, and (3) investigate potential sources. This paper focuses on Objective 3. All sites were situated within 15 km of 1000 MW electricity generating plants (EGPs) and major highways. Bi-weekly dry deposition and passive sampler Hg uptake were not directly correlated with the automated Tekran® system measurements, and there was limited agreement between these systems for periods of high deposition. Using diel, biweekly, and seasonal Hg observations, and ancillary data collected at each site, the potential sources of Hg deposited to surrogate surfaces were investigated. With this information, we conclude that there are three major processes/sources contributing to Hg dry deposition in Florida, with these varying as a function of location and time of year. These include: (1) in situ oxidation of locally and regionally derived Hg facilitated by mobile source emissions, (2) indirect and direct inputs of Hg from local EGPs, and (3) direct input of Hg associated with long range transport of air from the northeastern United States. Based on data collected with the surrogate surface sampling system, natural background dry deposition for Florida is estimated to be 0.03 ng m−2 h−1. Deposition associated with mobile sources is 0.10 ng m−2 h−1 at TPA and DVE, and 0.03 ng m−2 h−1 at OLF. Long range transport contributes 0.8 ng m−2 h−1 in the spring. At DVE ~0.10 ng m−2 h−1 is contributed directly or indirectly from local point sources. We also suggest based on the data collected with the Tekran® and passive sampling systems that different chemical forms of GOM are associated with each of these sources.

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