Bibeau B.C.,Air Resource Specialists Inc.
Air and Waste Management Association - Symposium on Air Quality Measurement Methods and Technology 2010 | Year: 2010
MODBUS TCP/IP digital data acquisition has proven to be a robust and reliable method for collecting data from monitoring instrumentation, including trace-level NCore instruments. Its many advantages over RS-232 include efficient integration, standard hardware, and low cost. Combining this method of data collection with high-speed internet access and manufacturer supplied software, remote maintenance and troubleshooting can help provide a fast response to problems, often without the need to physically visit the station. Source
Hand J.L.,Colorado State University |
Schichtel B.A.,National Park Service |
Malm W.C.,Colorado State University |
Copeland S.,Colorado State University |
And 3 more authors.
Atmospheric Environment | Year: 2014
Visibility has improved significantly at many remote areas across the United States since the early 1990s. Trends in visibility were calculated using ambient light extinction coefficients (bext) estimated from speciated particulate concentrations measured by the IMPROVE (Interagency Monitoring of Protected Visual Environments) network. The 20% haziest bext levels were computed for each year following Regional Haze Rule guidelines and aggregated over three major regions of the United States. Over the last two decades (1992-2011) the regional mean 20% haziest bext dropped by 52% (-2.6%yr-1, p<0.01) in the eastern United States, and by 20% (-1.0%yr-1, p=0.08) for sites along the West Coast. However, in the Intermountain/Southwest region, the trend was insignificant (-0.2%yr-1, p=0.36). Over the last decade (2002-2011) the haziest bext in the Intermountain/Southwest region decreased by 15% (-1.5%yr-1, p=0.09), compared to a decrease of 35% (-3.5%yr-1, p=0.06) in the West Coast region and 50% (-5.0%yr-1, p=0.02) in the East. A novel aspect to this study is the visualization of trends through the simulation of images of national parks and other remote areas for early and current haziest conditions. These images are an effective means for communicating trends and illustrate the dramatic improvement in visibility, especially in the East, where reductions in sulfate concentrations and sulfur dioxide emissions have had a positive impact on visibility degradation. However, while conditions are clearer for regions in the West, less improvement points to the need for understanding the influences on the trends in haziest conditions in those regions. © 2014 Elsevier Ltd. Source
Collaud Coen M.,Federal Office of Meteorology and Climatology |
Andrews E.,University of Colorado at Boulder |
Andrews E.,National Oceanic and Atmospheric Administration |
Asmi A.,University of Helsinki |
And 23 more authors.
Atmospheric Chemistry and Physics | Year: 2013
Currently many ground-based atmospheric stations include in-situ measurements of aerosol physical and optical properties, resulting in more than 20 long-term (> 10 yr) aerosol measurement sites in the Northern Hemisphere and Antarctica. Most of these sites are located at remote locations and monitor the aerosol particle number concentration, wavelength-dependent light scattering, backscattering, and absorption coefficients. The existence of these multi-year datasets enables the analysis of long-term trends of these aerosol parameters, and of the derived light scattering Ångström exponent and backscatter fraction. Since the aerosol variables are not normally distributed, three different methods (the seasonal Mann-Kendall test associated with the Sen's slope, the generalized least squares fit associated with an autoregressive bootstrap algorithm for confidence intervals, and the least-mean square fit applied to logarithms of the data) were applied to detect the long-term trends and their magnitudes. To allow a comparison among measurement sites, trends on the most recent 10 and 15 yr periods were calculated. No significant trends were found for the three continental European sites. Statistically significant trends were found for the two European marine sites but the signs of the trends varied with aerosol property and location. Statistically significant decreasing trends for both scattering and absorption coefficients (mean slope of-2.0% yr-1) were found for most North American stations, although positive trends were found for a few desert and high-altitude sites. The difference in the timing of emission reduction policy for the Europe and US continents is a likely explanation for the decreasing trends in aerosol optical parameters found for most American sites compared to the lack of trends observed in Europe. No significant trends in scattering coefficient were found for the Arctic or Antarctic stations, whereas the Arctic station had a negative trend in absorption coefficient. The high altitude Pacific island station of Mauna Loa presents positive trends for both scattering and absorption coefficients. © 2013 Author(s). Source
Gebhart H.,Air Resource Specialists Inc. |
Branscum I.,POET LLC
Proceedings of the Air and Waste Management Association's Annual Conference and Exhibition, AWMA | Year: 2014
A discussion on the current air emission and air permitting topics in the renewable fuels industry covers the greenhouse gas regulation on biorefinery sources; Project LIBERTY, an advanced biofuels project aiming to make cellulosic bio-ethanol competitive with corn bio-ethanol, the primary renewable liquid transportation fuel on the US market today, including the unique permitting challenges associated with the project, and how the EPA rules governing biogenic carbon impacts the plant permitting requirements; ongoing efforts to develop advanced biofuel projects within the State Of California and the environmental/permitting challenges faced by the project developers; the California Low Carbon Fuel Standard (LCFS); fuel pathways already approved under the LCFS, and the procedures required for new fuel pathways to be approved; and how biofuels production is treated under the LCFS as opposed to other types of advanced transportation fuels. This is an abstract of a paper presented at the AWMA's 107th Annual Conference & Exhibition (Long Beach, CA 6/24-27/2014). Source
Molenar J.V.,Air Resource Specialists Inc.
Air and Waste Management Association - Aerosol and Atmospheric Optics: Visibility and Air Pollution Specialty Conference 2012 | Year: 2012
Measurements and analyses have shown that the exceptionally high photochemical ozone production observed in the UGRB in winter is the result of NOx and VOC effluents released in the production of natural gas in the area. These effluents become contained within a relatively shallow stagnant, stable air layer near the surface. When there is extensive snow cover and clear skies, these emmisions are rapidly converted photochemically to ozone which is in turn also trapped in the shallow, stable boundary layer. We conclude by noting that similar cold temperature ozone formation is probably occurring in other regions of the western U.S., and in Canada, Russia, Kazakhstan, Mongolia and China where fossil fuel extraction occurs in similar terrain and under similar meteorological conditions. At present, ozone measurements in most of these regions in winter are limited to non-existent. Source