Atmospheric reduced nitrogen: Sources, transformations, effects, and management.

Human activities have increased atmospheric emissions and deposition of oxidized and reduced forms of nitrogen, but emission control programs have largely focused on oxidized nitrogen. As a result, in many regions of the world emissions of oxidized nitrogen are decreasing while emissions of reduced nitrogen are increasing. Emissions of reduced nitrogen largely originate from livestock waste and fertilizer application, with contributions from transportation sources in urban areas.

Modeling Emissions and Ozone Air Quality Impacts of Future Scenarios for Energy and Power Production in the Rocky Mountain States.

This study examines air quality impacts of scenarios for energy production and use in 2030 across Colorado, northern New Mexico, Utah, and Wyoming. Scenarios feature contrasting levels of oil and gas production and shares of electricity from coal, natural gas, and renewables. Hourly emissions are resolved for individual power plants; oil and gas emissions are basin-specific.

Emission Impacts of Electric Vehicles in the US Transportation Sector Following Optimistic Cost and Efficiency Projections.

This study investigates emission impacts of introducing inexpensive and efficient electric vehicles into the US light duty vehicle (LDV) sector. Scenarios are explored using the ANSWER-MARKAL model with a modified version of the Environmental Protection Agency's (EPA) 9-region database. Modified cost and performance projections for LDV technologies are adapted from the National Research Council (2013) optimistic case.

Increasing the Use of Earth Science Data and Models in Air Quality Management.

Unlabelled: In 2010, the U.S. National Aeronautics and Space Administration (NASA) initiated the Air Quality Applied Science Team (AQAST) as a 5-year, $17.

Managing Carbon on Federal Public Lands: Opportunities and Challenges in Southwestern Colorado.

Federal lands in the United States have been identified as important areas where forests could be managed to enhance carbon storage and help mitigate climate change. However, there has been little work examining the context for decision making for carbon in a multiple-use public land environment, and how science can support decision making. This case study of the San Juan National Forest and the Bureau of Land Management Tres Rios Field Office in southwestern Colorado examines whether land managers in these offices have adequate tools, information, and management flexibility to practice effective carbon stewardship.

Impacts of Foreign, Domestic, and State-Level Emissions on Ozone-Induced Vegetation Loss in the United States.

Exposure to elevated levels of ozone leads to yield reduction in agricultural crops and biomass loss in trees. Here, we quantify the impact of ozone pollution on two major U.S.

The short-term association of selected components of fine particulate matter and mortality in the Denver Aerosol Sources and Health (DASH) study.

Background: Associations of short-term exposure to fine particulate matter (PM2.5) with daily mortality may be due to specific PM2.5 chemical components.

Emissions implications of future natural gas production and use in the U.S. and in the Rocky Mountain region.

Enhanced prospects for natural gas production raise questions about the balance of impacts on air quality, as increased emissions from production activities are considered alongside the reductions expected when natural gas is burned in place of other fossil fuels. This study explores how trends in natural gas production over the coming decades might affect emissions of greenhouse gases (GHG), volatile organic compounds (VOCs) and nitrogen oxides (NOx) for the United States and its Rocky Mountain region. The MARKAL (MARKet ALlocation) energy system optimization model is used with the U.

Errors in coarse particulate matter mass concentrations and spatiotemporal characteristics when using subtraction estimation methods.

In studies of coarse particulate matter (PM10-2.5), mass concentrations are often estimated through the subtraction of PM2.5 from collocated PM10 tapered element oscillating microbalance (TEOM) measurements.

Unpacking the 'information barrier': comparing perspectives on information as a barrier to climate change adaptation in the interior mountain West.

Inadequate information has been repeatedly identified as a barrier to climate change adaptation planning and implementation. However less is known about how information functions as a barrier, and to what degree it prevents adaptation compared to other perceived barriers. In addition, the role of institutional context in mediating the demand for information in the context of adaptation has been less well studied.

Accounting for climate and air quality damages in future U.S. electricity generation scenarios.

The EPA-MARKAL model of the U.S. electricity sector is used to examine how imposing emissions fees based on estimated health and environmental damages might change electricity generation.

Positive matrix factorization of a 32-month series of daily PM speciation data with incorporation of temperature stratification.

This study presents source apportionment results for PM from applying positive matrix factorization (PMF) to a 32-month series of daily PM compositional data from Denver, CO, including concentrations of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solution was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutions with those from the base case solution. These eight factors were identified as inorganic ion, -alkane, EC/sterane, light -alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd -alkane.

Intra-urban spatial variability of PM-bound carbonaceous components.

The Denver Aerosol Sources and Health (DASH) study was designed to evaluate associations between PM species and sources and adverse human health effects. The DASH study generated a five-year (2003-2007) time series of daily speciated PM concentration measurements from a single, special-purpose monitoring site in Denver, CO. To evaluate the ability of this site to adequately represent the short term temporal variability of PM concentrations in the five county Denver metropolitan area, a one year supplemental set of PM samples was collected every sixth day at the original DASH monitoring site and concurrently at three additional sites.

Intra-urban spatial variability and uncertainty assessment of PM sources based on carbonaceous species.

To identify the sources of PM - bound carbonaceous species and examine the spatial variability of source contributions in the Denver metropolitan area, positive matrix factorization (PMF) was applied to one year of every sixth day ambient PM compositional data, including elemental carbon (EC), organic carbon (OC), and 32 organic molecular markers, from four sites (two residential and two near-traffic). Statistics (median, inner quantiles and 5 - 95 percentiles range) of factor contributions, expressed as reconstructed carbonaceous mass (EC + OC), were estimated from PMF solutions of replicate datasets generated by using a stationary block bootstrap technique. A seven-factor solution was resolved for a set of data pooled across the four sites, as it gave the most interpretable results and had the highest rate of neural network factor matching (76.

Positive matrix factorization of PM(2.5): comparison and implications of using different speciation data sets.

To evaluate the utility and consistency of different speciation data sets in source apportionment of PM(2.5), positive matrix factorization (PMF) coupled with a bootstrap technique for uncertainty assessment was applied to four different 1-year data sets composed of bulk species, bulk species and water-soluble elements (WSE), bulk species and organic molecular markers (OMM), and all species. The five factors resolved by using only the bulk species best reproduced the observed concentrations of PM(2.

Managing United States public lands in response to climate change: a view from the ground up.

Federal land managers are faced with the task of balancing multiple uses and goals when making decisions about land use and the activities that occur on public lands. Though climate change is now well recognized by federal agencies and their local land and resource managers, it is not yet clear how issues related to climate change will be incorporated into on-the-ground decision making within the framework of multiple use objectives. We conducted a case study of a federal land management agency field office, the San Juan Public Lands Center in Durango, CO, U.

Effects of plug-in hybrid electric vehicles on ozone concentrations in Colorado.

This study explores how ozone concentrations in the Denver, CO area might have been different if plug-in hybrid electric vehicles (PHEVs) had replaced light duty gasoline vehicles in summer 2006. A unit commitment and dispatch model was used to estimate the charging patterns of PHEVs and dispatch power plants to meet electricity demand. Emission changes were estimated based on gasoline displacement and the emission characteristics of the power plants providing additional electricity.

Source Apportionment Using Positive Matrix Factorization on Daily Measurements of Inorganic and Organic Speciated PM(2.5).

Particulate matter less than 2.5 microns in diameter (PM(2.5)) has been linked with a wide range of adverse health effects.

After the clean air mercury rule: prospects for reducing mercury emissions from coal-fired power plants.

Recent court decisions have affected the EPA's regulation of mercury emissions from coal burning, but some state laws are helping to clear the air.

Use of synthetic data to evaluate positive matrix factorization as a source apportionment tool for PM2.5 exposure data.

Positive matrix factorization (PMF) was applied to synthetic datasets that simulate personal exposures to airborne PM2.5 from 12 sources. Three differentfilter analysis scenarios using different analytical chemistry techniques were considered.

Prescribed burns and wildfires in Colorado: impacts of mitigation measures on indoor air particulate matter.

Wildfires and prescribed burns are receiving increasing attention as sources of fine particulate matter (PM2.5). The goal of this research project was to understand the impact of mitigation strategies for residences impacted by scheduled prescribed burns and wildfires.

Evaluation of incremental reactivity and its uncertainty in Southern California.

The incremental reactivity (IR) and relative incremental reactivity (RIR) of carbon monoxide and 30 individual volatile organic compounds (VOC) were estimated for the South Coast Air Basin using two photochemical air quality models: a 3-D, grid-based model and a vertically resolved trajectory model. Both models include an extended version of the SAPRC99 chemical mechanism. For the 3-D modeling, the decoupled direct method (DDM-3D) was used to assess reactivities.