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Aircraft activity at airports is a source of CO 2 emissions that affect the climate and other pollutants that affect air quality and human health. We estimate the air quality and climate benefits of two measures applied to aircraft operations at the Detroit Metropolitan Airport – pushback control and de-rated takeoffs. We also calculate the minimum air quality and environmental impacts beyond fuel burn and CO 2 minimization by optimizing gate holding and takeoff thrust hourly over the year. Pushback control (i.e. holding aircraft at their gates up to 25 min to reduce congestion) minimizes fuel burn and reduces emissions and air quality impacts from taxi operations by 35–38% relative to no gate holds. The PM 2.5 and O 3 costs can be further reduced beyond fuel burn minimization by 2.7% and 8.5%, respectively, by optimizing the gate holds according to time-varying atmospheric conditions. De-rated takeoffs (i.e. takeoffs at 75% thrust) reduce PM 2.5 costs from takeoff operations by 18% (up to 21.6% when optimized) relative to full-thrust takeoffs, but result in 3% increased fuel burn and CO 2 climate impacts. The environmental costs of takeoff operations are minimized with an average thrust setting of 81%, while total fuel combustion-related costs (i.e. the sum of environmental, fuel and maintenance costs) are minimized with 75% thrust. Our findings suggest that the pushback control strategy is effective in mitigating the environmental impacts of taxi operations at airports, and that de-rated takeoffs are effective in reducing the environmental costs of takeoff operations at an optimal level of de-rate. [ABSTRACT FROM AUTHOR]

Population exposure to daily maximum ozone is associated with an increased risk of premature mortality, and efforts to mitigate these impacts involve reducing emissions of nitrogen oxides (NO x ) and volatile organic compounds (VOCs). We quantify the dependence of U.S. national exposure to annually averaged daily maximum ozone on ambient VOC and NO x concentrations through ozone exposure isopleths, developed using emissions sensitivities from the adjoint of the GEOS-Chem air quality model for 2006. We develop exposure isopleths for all locations within the contiguous US and derive metrics based on the isopleths that quantify the impact of emissions on national ozone exposure. This work is the first to create ozone exposure isopleths using adjoint sensitivities and at a large scale. We find that across the US, 29% of locations experience VOC-limited conditions (where increased NO x emissions lower ozone) during 51% of the year on average. VOC-limited conditions are approximately evenly distributed diurnally and occur more frequently during the fall and winter months (67% of the time) than in the spring and summer (37% of the time). The VOC/NO x ratio of the ridge line on the isopleth diagram (denoting a local maximum in ozone exposure with respect to NO x concentrations) is 9.2 ppbC/ppb on average across grid cells that experience VOC-limited conditions and 7.9, 10.1 and 6.7 ppbC/ppb at the three most populous US cities of New York, Los Angeles and Chicago, respectively. Emissions that are ozone exposure-neutral during VOC-limited exposure conditions result in VOC/NO x concentration ratios of 0.63, 1.61 and 0.72 ppbC/ppb at each of the three US cities respectively, and between 0.01 and 1.91 ppbC/ppb at other locations. The sensitivity of national ozone exposure to NO x and VOC emissions is found to be highest near major cities in the US. Together, this information can be used to assess the effectiveness of NO x and VOC emission reductions on mitigating ozone exposure in the US, determine where they will be counterproductive, and quantify the optimal NO x /VOC reduction ratio. [ABSTRACT FROM AUTHOR]

Abstract: Combustion emissions adversely impact air quality and human health. A multiscale air quality model is applied to assess the health impacts of major emissions sectors in United States. Emissions are classified according to six different sources: electric power generation, industry, commercial and residential sources, road transportation, marine transportation and rail transportation. Epidemiological evidence is used to relate long-term population exposure to sector-induced changes in the concentrations of PM2.5 and ozone to incidences of premature death. Total combustion emissions in the U.S. account for about 200,000 (90% CI: 90,000–362,000) premature deaths per year in the U.S. due to changes in PM2.5 concentrations, and about 10,000 (90% CI: −1000 to 21,000) deaths due to changes in ozone concentrations. The largest contributors for both pollutant-related mortalities are road transportation, causing ∼53,000 (90% CI: 24,000–95,000) PM2.5-related deaths and ∼5000 (90% CI: −900 to 11,000) ozone-related early deaths per year, and power generation, causing ∼52,000 (90% CI: 23,000–94,000) PM2.5-related and ∼2000 (90% CI: −300 to 4000) ozone-related premature mortalities per year. Industrial emissions contribute to ∼41,000 (90% CI: 18,000–74,000) early deaths from PM2.5 and ∼2000 (90% CI: 0–4000) early deaths from ozone. The results are indicative of the extent to which policy measures could be undertaken in order to mitigate the impact of specific emissions from different sectors — in particular black carbon emissions from road transportation and sulfur dioxide emissions from power generation. [Copyright &y& Elsevier]

Abstract: The air quality impacts of aviation are becoming increasingly important given their impact on human health and the projected growth of aviation. In the United States, the government has set targets to manage and reduce the environmental impacts of aviation. In an environmental policy assessment context it is often necessary to rapidly evaluate many possible scenarios, and quantification of uncertainty is important. This makes direct application of comprehensive air quality models such as the Community Multiscale Air Quality (CMAQ) modeling system impractical due to computational cost. Here we develop a response surface model (RSM) – a form of rapid surrogate model – of the impact of aviation emissions on air quality in the United States. We develop an RSM design space and populate it with results from 46 CMAQ simulations, and perform cross-validation of the resultant RSM. The RSM models present-day as well as future impacts amid changing population and non-aviation emissions sources. This enables rapid estimates of the (particulate matter) air quality and human health impacts of aviation emissions scenarios. Cross-couplings between precursor gaseous emissions and PM2.5 species are found, consistent with competition for atmospheric ammonia. We apply the RSM to quantify the human health benefits of emissions reductions in 2018. Using the RSM we estimate that in 2005, aviation landing and takeoff emissions cause ∼195 [90% CI: 80–340] early deaths, while the same emissions cause ∼350 [90% CI: 145–610] mortalities in 2018. An emissions tradespace between aviation NO x and SO x emissions is constructed. It is found that with fleet-wide desulfurization of jet fuel, a 35% reduction in aviation NO x emissions would result in maintaining the same level of aviation-attributable early deaths in 2018 relative to 2005 levels, while an 80% reduction in NO x emissions would half aviation-attributable early deaths. [Copyright &y& Elsevier]

In the United States, general aviation piston-driven aircraft are now the largest source of lead emitted to the atmosphere. Elevated lead concentrations impair children's IQ and can lead to lower earnings potentials. This study is the first assessment of the nationwide annual costs of IQ_ losses from aircraft lead emissions. We develop a general aviation emissions inventory for the continental United States and model its impact on atmospheric concentrations using the community multi-scale air quality model (CMAQ). We use these concentrations to quantify the impacts of annual aviation lead emissions on the U.S. population using two methods: through static estimates of cohort-wide IQ, deficits and through dynamic economy-wide effects using a computational general equilibrium model. We also examine the sensitivity of these damage estimates to different background lead concentrations, showing the impact of lead controls and regulations on marginal costs. We find that aircraft-attributable lead contributes to $1.06 billion 2006 USD ($0.01--$11.6) in annual damages from lifetime earnings reductions, and that dynamic economy-wide methods result in damage estimates that are 54% larger. Because the marginal costs of lead are dependent on background concentration, the costs of piston-driven aircraft lead emissions are expected to increase over time as regulations on other emissions sources are tightened. [ABSTRACT FROM AUTHOR]

Abstract: With the projected growth in demand for commercial aviation, many anticipate increased environmental impacts associated with noise, air quality, and climate change. Therefore, decision-makers and stakeholders are seeking policies, technologies, and operational procedures that balance environmental and economic interests. The main objective of this paper is to address shortcomings in current decision-making practices for aviation environmental policies. We review knowledge of the noise, air quality, and climate impacts of aviation, and demonstrate how including environmental impact assessment and quantifying uncertainties can enable a more comprehensive evaluation of aviation environmental policies. A comparison is presented between the cost-effectiveness analysis currently used for aviation environmental policy decision-making and an illustrative cost–benefit analysis. We focus on assessing a subset of the engine NO X emissions certification stringency options considered at the eighth meeting of the International Civil Aviation Organization’s Committee on Aviation Environmental Protection. The FAA Aviation environmental Portfolio Management Tool (APMT) is employed to conduct the policy assessments. We show that different conclusions may be drawn about the same policy options depending on whether benefits and interdependencies are estimated in terms of health and welfare impacts versus changes in NO X emissions inventories as is the typical practice. We also show that these conclusions are sensitive to a variety of modeling uncertainties. While our more comprehensive analysis makes the best policy option less clear, it represents a more accurate characterization of the scientific and economic uncertainties underlying impacts and the policy choices. [ABSTRACT FROM AUTHOR]

Aircraft noise, air quality, and climate change damages are spatially and temporally heterogeneous. While policymakers often focus on aggregate cost-benefit analysis to examine tradeoffs in aviation environmental policy, these analyses do not always indicate who bears the costs or who gains the benefits of aviation. We model both the net cost and distribution of environmental damages from one year of aviation operations across the three environmental domains. We find that populations living at airport boundaries face damages of $100–400 per person per year from aircraft noise and between $5–16 per person per year from climate damages (in 2006 dollars). Expected damages from air quality are dependent on the number of operations at the airport and range from $20 to over $400 per person per year with air quality damages approaching those of noise at high volume airports. Mean expected noise and air quality damages decay with distance from the airport, but for noise, the range of expected damages at a given distance can be high and depends on orientation with respect to runways and flight patterns. Damages from aviation-induced climate change dominate those from local air quality degradation and noise pollution further away from the airport. However, air quality damages may exceed those from climate when considering the impact of cruise emissions on air quality. [ABSTRACT FROM AUTHOR]

In jurisdictions including the US and the EU ground transportation and marine fuels have recently been required to contain lower concentrations of sulfur, which has resulted in reduced atmospheric SOx emissions. In contrast, the maximum sulfur content of aviation fuel has remained unchanged at 3000 ppm (although sulfur levels average 600 ppm in practice). We assess the costs and benefits of a potential ultra-low sulfur (15 ppm) jet fuel standard ("ULSJ"). We estimate that global implementation of ULSJ will cost US$1-4bn per year and prevent 900-4000 air quality-related premature mortalities per year. Radiative forcing associated with reduction in atmospheric sulfate, nitrate, and ammonium loading is estimated at +3.4 mW/m2 (equivalent to about 1/10th of the warming due to CO2 emissions from aviation) and ULSJ increases life cycle CO2 emissions by approximately 2%. The public health benefits are dominated by the reduction in cruise SOx emissions, so a key uncertainty is the atmospheric modeling of vertical transport of pollution from cruise altitudes to the ground. Comparisons of modeled and measured vertical profiles of CO, PAN, O3, and 7Be indicate that this uncertainty is low relative to uncertainties regarding the value of statistical life and the toxicity of fine particulate matter. [ABSTRACT FROM AUTHOR]