Research

HMSThe Role of Formaldehyde in Particulate Air Pollution Control

 

BACKGROUND:

Controlling formaldehyde can be an important lever for reducing particulate air pollution. Hydroxymethanesulfonate (HMS) is formed by the aqueous phase reaction of formaldehyde and sulfite or bisulfite. While HMS chemistry is well understood and was included in many early atmospheric chemistry models, this chemical pathway has been mostly overlooked since the late 1980s. Importantly, HMS can be confused for sulfate in measurements. This may have led to the misidentification of HMS as sulfate in measurements of PM2.5 chemical composition. This implies that, where HMS comprises a significant portion of particulate sulfur, reductions of formaldehyde may also be an effective tool at reducing particulate air pollution.

OBJECTIVES:

  • Understand the significance of HMS in particulate matter during extreme haze in China;
  • Determine the importance of HMS globally;
  • Determine the effectiveness of reducing formaldehyde versus reducing sulfur dioxide for PM2.5 concentrations.

REFERENCES:

  • Moch, J.M., E. Dovrou, L.J. Mickley, F.N. Keutsch, Z. Liu, Y. Wang, T.L. Dombek, M. Kuwata, S.H. Budisulistiorini, L. Yang, S. Decesari, M. Paglione, B. Alexander, J. Shao, J.W. Munger, D.J. Jacob, Global importance of hydroxymethanesulfonate in ambient particular matter: Implications for air quality, accepted to J. Geophys. Res., 2020. [PDFSupplement].
  • Moch, J.M., E. Dovrou, L.J. Mickley, F.N. Keutsch, Y. Cheng, D.J. Jacob, J. Jiang, M. Li, J.W. Munger, X. Qiao, and Q. Zhang, Contribution of hydroxymethane sulfonate to ambient particulate matter: A potential explanation for high particulate sulfur during severe winter haze in Beijing, Geophys. Res. Lett., 2018. [PDF, Supplement]

China_hazeClimate Effects of Chinese Air Pollution 

 

BACKGROUND:

Fine particle air pollution, also called PM2.5 or aerosols, can exert an influence on climate through interactions with solar radiation and clouds. Aerosols often affect climate in ways that enhance PM2.5 concentrations, and therefore reducing PM2.5 can lead to a climate bonus where local and regional climate is modified so that the meteorological conditions that promote a buildup of air pollution are less likely. However, this change in climate due to reduced aerosols is also generally accompanied by a local warming and can lead to changes in regional circulation patterns. In the past, examining the combined effects of these local and regional changes to climate due to aerosols has been limited by constrained representations of either chemistry or physics in models. Because China has such a heavy air pollution burden, it represents a good case study region for examining the effects of aerosols on climate.

OBJECTIVES:

  • Fully couple the GEOS-Chem atmospheric chemistry model to NASA's GEOS climate model;
  • Use the new coupled GEOS-GEOS-Chem (GEOS-GC) climate-chemistry model to examine the climate impacts of reductions in Chinese air pollution since 2013;
  • Determine the effect of aerosol-driven changes to climate on surface air pollution concentrations and public health.

REFERENCES:

  •  Li, K., H. Liao, J. Zhu, and J.M. Moch, Implications of RCP emissions on future PM2.5 air quality and direct radiative forcing over China, J. Geophys. Res., 2016. [PDF].

geoengineering Solar Geoengineering and Public Health 

 

BACKGROUND:

Solar geoengineering is a proposed strategy for attempting to reduce some damages from climate change and supplement mitigation efforts by reflecting a small fraction of the sunlight that Earth receives back into space, thereby slightly cooling the planet. The most commonly proposed method for solar geoengineering is to inject sulfate aerosols into the stratosphere. Geoengineering might reduce some climate risks such as extreme temperatures, but there remain significant uncertainties and risks surrounding geoengineering. One risk is the effect geoengineering may have on public health. Since solar geoengineering impacts sunlight, it will change atmospheric photochemistry with unclear consequences for surface pollution concentrations and surface levels of UV radiation, both of which can influence mortality.

OBJECTIVES:

  • Implement solar geoengineering by stratospheric aerosol injection into the GEOS-Chem atmospheric chemistry model;
  • Estimate the public health impacts of geoengineering;
  • Estimate the additional radiative forcing due to atmospheric composition changes induced by geoengineering.

BC particleCo-Production of Environmental Politics and Black Carbon Aerosol  

 

BACKGROUND:

The reduction of black carbon, a component of atmospheric particulate matter, is often referred to as a ‘win-win’ for climate and air quality. However, this common framing of black carbon overlooks the fact that improvement in air quality from black carbon reduction is due mostly to reductions in pollutants co-emitted with black carbon and that most of these pollutants co-emitted with black carbon are reflective and therefore their removal has a warming impact on the climate. The framework of co-production, which hold that science and society underwrite each other's existence, can provide an explanation for how the commonly used definition of black carbon came to embody these contradictions.

OBJECTIVES:

  • Trace the history of definitions of black carbon aerosol and how various definitions reflected environmental problems of the time;
  • Examine how various competing definitions for black carbon got combined, eventually leading to the idea of black carbon as a 'win-win' for climate and health;
  • Develop recommendations for how to better characterize carbonaceous aerosols for the purposes of implementing policies to improve public health and mitigate climate change.

The Tesla Semi Truck (40705940423).jpg  Electric Vehicle Policy Challenges and Environmental Implications 

 

BACKGROUND:

Electric vehicles (EV), both passenger and commercial, will play an essential part of solutions that aim to reduce global greenhouse gas emissions and mitigate anthropogenic climate change. However, as EV technology is new and evolving, many challenges remain to widespread EV deployment, such as the development of sufficient charging infrastructure. Furthermore, given the varied contexts in which EVs may be used, the economic and environmental benefits are not always easily quantifiable.

OBJECTIVES:

  • Identify policy challenges for widespread deployment of passenger and commercial electric vehicles and potential solutions;
  • Quantify the impacts of long haul truck electrification in high demand regions such as China;
  • Identify challenges to using EVs to support renewable energy on the electric grid (vehicle to grid) and potential solutions.

REFERENCES:

  • Moch, J.M., Environmental Implications and Policy Challenges for Bringing Long-Haul Electric Trucks into China: The Case of the Tesla Semi, Environment and Natural Resources Program, Belfer Center Paper, 2019. [PDF]
  • Moch, J.M. Plug-in Vehicles and Vehicle to Grid TechnologyRenewable Energy and the Electric Grid in the U.S. Task Force for Princeton University School of Public and International Affairs, 2011. [PDF]

 

cloud_pHCloud and Rain Acidity 

 

BACKGROUND:

Cloud acidity is determined by a balance between acids and bases, including buffering effects that are not well understood. Being able to model cloud acidity is of key importance for in-cloud chemistry relevant to sulfate formation, halogen cycling, and organic aerosol formation. Cloud acidity is closely tied to rain acidity, which has a range of effects on ecosystems.

OBJECTIVES:

  • Develop a new capability for simulating cloud and rain acidity in GEOS-Chem;
  • Apply it to improve the model representations of sulfate and halogen chemistry through better representation of in-cloud processes;
  • Provide a framework for understanding how future changes in emissions will affect cloud and rain acidity.

REFERENCES:

  • Shah, V., D.J. Jacob, J.M. Moch, X. Wang, and S. Zhai, Global modeling of cloudwater acidity, precipitation acidity, and acid inputs to ecosystemsAtmos. Chem. Phys. Discuss., 2020. [PDF]
  • Moch, J.M., E. Dovrou, L.J. Mickley, F.N. Keutsch, Z. Liu, Y. Wang, T.L. Dombek, M. Kuwata, S.H. Budisulistiorini, L. Yang, S. Decesari, M. Paglione, B. Alexander, J. Shao, J.W. Munger, D.J. Jacob, Global importance of hydroxymethanesulfonate in ambient particular matter: Implications for air quality, accepted to J. Geophys. Res., 2020. [PDFSupplement].
  • Luo, G., F. Yu, and J.M. Moch, Further improvement of wet process treatments in GEOS-Chem v12.6.0: impact on global distributions of aerosols and aerosol precursorsGeophys. Model Dev., 2020. [PDF]

 

permafrostMethane Emissions from Arctic Permafrost 

 

BACKGROUND:

Permafrost, subsurface soil or rock that remains frozen year round, contains large amounts of frozen organic carbon. When permafrost thaws, as is projected to occur more frequently as climate change progresses, this organic carbon can be decomposed by microorganisms and released into the atmosphere as carbon dioxide or as methane depending on conditions. However, microorganisms also exist in the soil that can consume methane and release it as carbon dioxide. Since methane is a more potent greenhouse gas than carbon dioxide, whether decomposed organic carbon is released as carbon dioxide or methane can make a big difference for the effect of thawing permafrost on climate.

OBJECTIVES:

  • Develop a computer model for the dynamics of methane emissions and consumption for arctic permafrost;
  • Understand the factors that influence arctic permafrost methane emissions;
  • Predict how methane emissions from arctic permafrost will respond to climate change.

REFERENCES:

  • Oh, Y., B. Stackhouse, M.C.Y. Lau, X. Xu, A.T. Trugman, J.M. Moch, T.C. Onstott, C.J. Jørgensen, L. D’Imperio, B. Elberling, C.A. Emmerton, V.S. St. Louis, D. Medvigy, A scalable model for methane consumption in arctic mineral soils, Geophys. Res. Lett., 2016. [PDF]

US-China_cooperationU.S.-China Cooperation on Climate and Energy Policy 

 

BACKGROUND:

The United States and China are the world's two largest emitters of greenhouse gases that cause climate change. Solving climate change therefore requires both the U.S. and China to take significant action to reduce greenhouse gas emissions. In the run-up to the Paris Climate Agreement the U.S. and China began working together on multiple fronts regarding climate and energy policy and the momentum gained from those efforts helped push the Paris Agreement across the finish line. Cooperation between the U.S. and China on climate and energy policy has therefore already been essential in shaping the global effort to address the challenge of climate change and cooperation between the two countries remains critical for further progress.

OBJECTIVES:

  • Identify and suggest opportunities for U.S.-China collaboration on climate and energy policy;
  • Build and sustain momentum for further U.S.-China collaborative efforts on climate;
  • Build and support cross country collaborations at the non-governmental organization level.

REFERENCES:

  • Forbes, S., and J.M. Moch, How U.S.-China Cooperation Can Expand Clean Energy Development, WRI: Insights, 2014. [Link].
  • Moch, J.M., and S. Forbes, Recent Progress Shows China’s Leadership on Carbon Capture and Storage, WRI: Insights, 2013. [Link].
  • Igusky, K. and J.M. Moch, 3 Big Takeaways from the New Global Commitment to Phase Down HFCs, WRI: Insights, 2013. [Link].
  • Moch, J.M., 4 Promising Themes Emerge in U.S.-China Agreements at Strategic and Economic Dialogue, WRI: Insights, 2013. [Link].