Household Demand for Broadband Internet Service

As part of the Federal Communications Commission (“FCC”) National Broadband Report to Congress, we have been asked to conduct a survey to help determine consumer valuations of different aspects of broadband Internet service. This report details our methodology, sample and preliminary results. We do not provide policy recommendations. This draft report uses data obtained from a nationwide survey during late December 2009 and early January 2010 to estimate household demand for broadband Internet service. The report combines household data, obtained from choices in a real market and an experimental setting, with a discrete-choice model to estimate the marginal willingness-to-pay (WTP) for improvements in eight Internet service characteristics.

Instrument to collect fogwater for chemical analysis

An instrument is presented which collects large samples of ambient fogwater by impaction of droplets on a screen. The collection efficiency of the instrument is determined as a function of droplet size, and it is shown that fog droplets in the range 3–100-µm diameter are efficiently collected. No significant evaporation or condensation occurs at any stage of the collection process. Field testing indicates that samples collected are representative of the ambient fogwater. The instrument may easily be automated, and is suitable for use in routine air quality monitoring programs

The H_2SO_4-HNO_3-NH_3 System at High Humidities and in Fogs: 1. Spatial and Temporal Patterns in the San Joaquin Valley of California

A systematic characterization of the atmospheric H_2SO_4-HNO_3-NH_3 system was conducted in the fog water, the aerosol, and the gas phase at a network of sites in the San Joaquin Valley of California. Spatial patterns of concentrations were established that reflect the distribution of SO_2, NO_x, and NH_3 emissions within the valley. The concept of atmospheric alkalinity was introduced to interpret these concentrations in terms of the buffering capacity of the atmosphere with respect to inputs of strong acids. Regions of predominantly acidic and alkaline fog water were identified. Fog water was found to be alkaline in most of the valley, but small changes in emission budgets could lead to widespread acid fog. An extended stagnation episode was studied in detail: progressive accumulation of H_2SO_4-HNO_3-NH_3 species was documented over the course of the episode and interpreted in terms of production and removal mechanisms. Secondary production of strong acids H_2SO_4 and HNO_3 under stagnant conditions resulted in a complete titration of available alkalinity at the sites farthest from NH_3 sources. A steady SO_2 conversion rate of 0.4–1.1% h^(−1) was estimated in the stagnant mixed layer under overcast conditions and was attributed to nonphotochemical heterogeneous processes. Removal of SO_2 was enhanced in fog, compared to nonfoggy conditions. Conversion of NO_x to HNO_3 slowed down during the stagnation episode because of reduced photochemical activity; fog did not appear to enhance conversion of NO_x. Decreases in total HNO_3 concentrations were observed upon acidification of the atmosphere and were attributed to displacement of NO_3− by H_2SO_4 in the aerosol, followed by rapid deposition of HNO_3(g). The occurrence of fog was associated with general decreases of aerosol concentrations due to enhanced removal by deposition

Fogwater chemistry in an urban atmosphere

Analyses of fogwater collected by inertial impaction in the Los Angeles basin and the San Joaquin Valley indicated unusually high concentrations of major and minor ions. The dominant ions measured were NO_3^−, SO_4^(2−), NH_4^+, and H^+. Nitrate exceeded sulfate on an equivalent basis by a factor of 2.5 in the central and coastal regions of the Los Angeles basin but was approximately equal in the eastern Los Angeles basin and the San Joaquin Valley. Maximum observed values for NH_4^+, NO_3^−, and SO_4^(2−) were 10.0, 12.0, and 5.0, meq 1^(−1), while the lowest p;H observed was 2.2. Iron and lead concentrations of over 0.1 mM and 0.01 mM, respectively, were observed. High concentrations of chemical components in fog appeared to correlate well with the occurrence of smog events. Concentrations in fogwater were also affected by the physical processes of condensation and evaporation. Light, dissipating fogs routinely showed the highest concentrations

The H_2SO_4-HNO_3-NH_3 System at High Humidities and in Fogs: 2. Comparison of Field Data With Thermodynamic Calculations

Concentrations of HNO_3(g) and NH_3(g) determined in the field were compared to predictions from aerosol equilibrium models. The products of HNO_3(g) and NH_3(g) concentrations measured under cool and humid nonfoggy conditions agreed in magnitude with predictions from a comprehensive thermodynamic model for the atmospheric H_2SO_4-HNO_3-NH_3-H_2O system. Observed concentrations of NH_3(g) in fogs were generally consistent with those predicted at equilibrium with fog water, but important discrepancies were noted in some cases. These discrepancies may be due to fluctuations in fog water composition over the course of sample collection or to the sampling of nonfoggy pockets of air present within the fog. Detectable concentrations of HNO_3(g) (up to 23 neq m^(−3)) were often found in fogs with pH 5 were below the detection limit of 4–8 neq m^(−3)

Characterization of Reactants Reaction Mechanisms and Reaction Products Leading to Extreme Acid Rain and Acid Aerosol Conditions in Southern California

Analyses of fogwater collected by inertial impaction in the Los Angeles basin and the San Joaquin Valley indicated unusually high concentrations of major and minor ions. The dominant ions measured were NO_3^-, SO_4^(2-), NH_4^+ and H^+ Nitrate exceeded sulfate on an equivalent basis by a factor of 2.5 in the central and coastal regions of the Los Angeles basin, but was approximately equal in the eastern Los Angeles basin and the San Joaquin Valley. Maximum observed values for NH_4^+, NO_3^- and SO_4^(2-) were 10., 12., and 5. meq L^(-1), while the lowest pH observed was 2.2. Iron and lead concentrations over 0.1 mM and 0.01 mM, respectively, were observed. High concentrations of chemical components in fog appeared to correlate well with the occurrence of smog events. Concentrations in fogwater were also affected by the physical processes of condensation and evaporation. Light, dissipating fogs routinely showed the highest concentrations. The chemistry of urban fog has been modelled using a hybrid kinetic and equilibrium computer code. Extreme acidity found in Southern California fog may be due either to condensation and growth on acidic condensation nuclei or in situ S(IV) oxidation. Important oxidants of S(IV) were found to be O_2 as catalyzed by Fe(III) and Mn(II), H_2)_2 and 0_3. formation of hydroxymethane sulfonate ion (HMSA) via the nucleophilic addition of HSO_3^-to CH_2 CH_2O(ℓ) significantly increased the droplet capacity for S(IV) but did not slow down the net S(IV) oxidation rate leading to fog acidification. Gas phase nitric acid, ammonia and hydrogen peroxide were scavenged efficiently, although aqueous phase hydrogen peroxide was depleted rapidly by reduction with S(IV). Nitrate production in the aqueous phase was found to be dominated by HNO_3 gas phase scavenging. Major aqueous-phase species concentrations were controlled primarily by condensation, evaporation, and pH