Future year ozone source attribution modeling study using CMAQ-ISAM.

To achieve the current United States National Ambient Air Quality Standards (NAAQS) attainment level for ozone or particulate matter, current photochemical air quality models include tools to determine source apportionment and/or source sensitivity. Previous studies by the authors have used the Ozone and Particulate Matter Source Apportionment Technology and Higher-order Decoupled Direct Method probing tools in CAMx to investigate these source-receptor relationships for ozone. The recently available source apportionment for CMAQ, referred to as the Integrated Source Apportionment Method (ISAM), was used in this study to conduct future year (2030) source attribution modeling.

Future-year ozone prediction for the United States using updated models and inputs.

Unlabelled: The relationship between emission reductions and changes in ozone can be studied using photochemical grid models. These models are updated with new information as it becomes available. The primary objective of this study was to update the previous Collet et al.

Implementation and application of sub-grid-scale plume treatment in the latest version of EPA's third-generation air quality model, CMAQ 5.01.

Unlabelled: The Community Multiscale Air Quality (CMAQ) modeling system Version 5.0 (CMAQv5.0) was released by the US.

Evaluation of light-duty vehicle mobile source regulations on ozone concentration trends in 2018 and 2030 in the western and eastern United States.

To improve U.S. air quality, there are many regulations on-the-way (OTW) and on-the-books (OTB), including mobile source California Low Emission Vehicle third generation (LEV III) and federal Tier 3 standards.

A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3).

Global source attribution for mercury deposition in the United States.

A multiscale modeling system that consists of a global chemical transport model (CTM) and a nested continental CTM was used to simulate the global atmospheric fate and transport of mercury and its deposition over the contiguous United States. The performance of the CTMs was evaluated against available data. The coefficient of determination (r2) for observed versus simulated annual mercury wet deposition fluxes over North America was 0.

On the effect of spatial resolution on atmospheric mercury modeling.

Mathematical modeling of the atmospheric fate and transport of mercury (Hg) was conducted using three nested domains covering global, continental and regional scales with horizontal resolutions of approximately 1000, 100 and 20 km, respectively. Comparisons of modeling results with wet deposition fluxes show a coefficient of determination (r(2)) of 0.45 for the continental simulation and 0.

Simulation of Sulfate and Nitrate Chemistry in Power Plant Plumes.

The rate of formation of secondary particulate matter (PM) in power plant plumes varies as the plume material mixes with the background air. Consequently, the rate of oxidation of sulfur dioxide (SO) and nitrogen dioxide (NO) to sulfate and nitric acid, respectively, can be very different in plumes and in the background air (i.e.

The Development of a Model to Examine Source-Receptor Relationships for Visibility on the Colorado Plateau.

This paper describes the development and application of the Visibility and Haze in the Western Atmosphere (VISHWA) model to understand the source-receptor relationships that govern chemical species relevant to visibility degradation in the western United States. The model was developed as part of a project referred to as Visibility Assessment for Regional Emission Distributions (VARED), the objective of which is to estimate the contributions of various geographical regions, compounds, and emission sources to light scattering and absorption by particles on the Colorado Plateau. The VISHWA model is a modified version of a comprehensive Eulerian model, known as the Acid Deposition and Oxidant Model.