Emissions, air quality and heat in urban areas: CSU researchers receive over $2.2 million

nyc skyline

The Climate Program Office at NOAA has announced research funding that increases understanding of emissions – and chemical transformation of those emissions – in the urban atmosphere. Four of the 10 new projects have gone to Colorado State University researchers, totaling over $2.2 million to CSU.

The federal research program, called Atmospheric Chemistry, Carbon Cycle, and Climate, competitively selected projects that total $5.48 million in grants.

Urban air quality

Despite decades of decline in ground-level ozone and fine particulate matter, many U.S. metropolitan areas still violate the eight-hour ozone standard as regulated under the Clean Air Act. This could be a result of unanticipated trends in emissions, increasing influence of regional background sources, long-range transport of emissions, changes in atmospheric chemistry, and/or a consequence of a changing climate with heat waves in the United States becoming more frequent, longer in duration, and more intense. In fact, warming climate and increasing episodes of extreme heat – because they exacerbate air quality – require higher emission reductions to meet air quality standards.

Recent research has also revealed major gaps in the understanding of urban chemistry. In urban atmospheres, volatile chemical products like coatings, adhesives, inks, personal care products and cleaning agents are emerging as major sources of volatile organic compounds that have harmful environmental and health impacts.

The emissions and impacts of volatile chemical products on atmospheric chemistry are not well understood. In the presence of nitrogen oxides, volatile organic compounds undergo chemistry that leads to the formation of ground-level ozone and aerosols. In a pilot study, field measurements in New York City revealed that fragrant consumer products, such as air freshener, and other volatile chemical products account for over half of anthropogenic VOC emissions and enhance the formation of ground-level ozone during a heatwave event. Ground-level ozone can trigger a variety of health problems in children, the elderly and people of all ages who have lung diseases such as asthma.

To improve understanding of emissions and chemical reactions that affect urban air quality and climate, the NOAA Chemical Sciences Laboratory is planning the Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas (AEROMMA) aircraft-based field campaign to collect new observations from megacities to marine environments, currently scheduled for the summer of 2023. CSU researchers will support and participate in the AEROMMA aircraft campaign in a variety of ways.

Here are CSU’s funded projects:

Near Real-Time Aerosol Composition Measurements during the Atmospheric Emissions and Reactions Observed from Megacities to Marine Areas

Lead: Amy Sullivan, research scientist, Department of Atmospheric Science
Collaborator: Rodney Weber, Georgia Institute of Technology

This project will make particle-into-liquid-sampler measurements on the AEROMMA WP-3 NOAA aircraft to provide aerosol composition data for the AEROMMA campaign. The proposed measurement protocol comprises a well-established aerosol collection device that provides a liquid sample containing dissolved aerosol particles that can be analyzed by various methods. These measurements will provide high chemical specificity of sulfur species to complement other aerosol composition measurements to be deployed, such as aerosol mass spectrometry, and will be used to address the following research questions: What are the differences in the type of sulfate observed in urban vs. marine emissions? How important of a source is biomass burning in the study region during summer? How does it compare to winter? What is the pH of the aerosol in the study region in summer? How does it compare to winter? Overall, the project will provide information that could guide emission control strategies and meet air quality standards for protecting human health.

Ammonia for AEROMMA

Lead: Ilana Pollack, research scientist, Department of Atmospheric Science
Collaborators: Associate Professor Emily Fischer, Professor Jeffrey Pierce, Department of Atmospheric Science

Coastal megacities like Los Angeles and New York City experience some of the worst air quality in the United States. The Summer 2021 AEROMMA field campaign will address precursor emissions, pollutant formation and transport between megacities and marine environments. Gas-phase ammonia will be an essential observation during the AEROMMA study. Ammonia is an unregulated air pollutant that contributes to fine particle formation and nitrogen deposition. However, our observations of the atmospheric sources, sinks and phase partitioning of ammonia are limited compared to other major anthropogenic pollutants. In contrast to declining emissions of nitrogen oxide from combustion sources, the emissions of ammonia from combustion and agricultural activities have grown and the deposition of reduced nitrogen has increased. Ammonia emissions, particularly from vehicular sources in urban areas, are not well understood. This project will deploy a flight-ready quantum-cascade tunable infrared laser direct absorption spectrometer aboard the NOAA WP-3 aircraft to provide observations of gas-phase ammonia for the AEROMMA field campaign. The ammonia measurements and analysis objectives will provide information about the abundances and emissions of ammonia relative to other regulated pollutants as well as the chemical processes leading to fine particle formation in megacity and marine environments. This information will aid in guiding emission control strategies and policies.

Understanding the Emerging Contribution of Volatile Chemical Products and Food Cooking to Air Quality, the Aerosol Size Distribution, and Climate-Relevant Properties Over Urban to Regional Scales

Lead: Shantanu Jathar, Department of Mechanical Engineering
Collaborator: Jeffrey Pierce, Department of Atmospheric Science

Read more about this project, as well as Jathar’s funding from NSF. 

While emissions from traditional sources have been strictly controlled, newly identified sources, namely volatile chemical products and food cooking, may contribute substantially to the atmospheric chemistry and composition as well as air quality from urban to regional scales. The goal of this study is to understand the emerging role of volatile chemical products and food cooking emissions on ozone and organic aerosol, as well as the aerosol size distribution in the urban atmosphere, in the evolving downwind plume, and on regional aerosol properties. The project has three objectives. In Objective 1, recent laboratory data will be leveraged to develop mechanisms and parameterizations to represent ozone and aerosol formation from volatile chemical products and cooking sources. In Objective 2, aircraft observations and plume-model simulations will be used to understand the formation and evolution of ozone and aerosol mass, size and composition in urban plumes, sampled during the AEROMMA field campaign. In Objective 3, the mechanisms and parameters developed and evaluated in the previous objectives will be used in a regional chemistry-climate model to simulate the atmospheric chemistry and air quality in New York City and four other North American cities studied during the AEROMMA field campaign. The plume-model and climate model simulations will quantify the contribution of volatile chemical products and cooking sources to the urban and regional, ozone and aerosol burden and test if the inclusion of these sources improves the model performance in these cities.

Fluxes of Reactive Organic Gases in New York: Direct Quantification by Multi-Instrument Eddy Covariance in Support of AEROMMA

Lead: Delphine Farmer, Department of Chemistry
Collaborators: Dylan Millet and Timothy Griffis, University of Minnesota

Urban volatile organic compound emissions contribute to smog through formation of ozone and secondary organic aerosols. Quantifying urban volatile organic compound sources is a major challenge of importance for air quality and for understanding the reactive carbon cycle. This project will help address this by directly quantifying the urban flux of reactive carbon using an atmospheric turbulence measurement called eddy covariance.

Specifically, the project applies two complementary time-of-flight chemical ionization mass spectrometers to measure fluxes, gradients and concentrations of an expansive suite of reactive volatile organic compounds from a tower in metropolitan New York as part of AEROMMA. The measurements will make a key contribution to the broader AEROMMA campaign by sampling a predominantly residential footprint that represents a critical component of the diverse New York landscape. The project provides significant broader impacts to the scientific community and to the general public through: enhanced volatile organic compound understanding for improving atmospheric models; better source apportionment for more accurate air quality predictions; and unique opportunities for public engagement around the science of air pollution.

What scientific objectives do the grants support?

In fiscal year 2021, the Atmospheric Chemistry, Carbon Cycle and Climate program focused on a subset of AEROMMA by seeking to support studies of emissions and chemical transformation in the urban atmosphere. Specifically, the program is supporting the types of projects that:

• Determine organics emissions and chemistry, including of understudied volatile chemical products to better understand the impact on ozone and aerosol formation, and to study their relative importance on urban air quality compared to other sources of volatile organic compounds such as from energy-related, cooking and natural sources.
• Determine reactive nitrogen emissions and chemistry in urban corridors to understand the current importance of combustion and non-combustion sources, continue the trend analysis and determine changes in the reactive nitrogen cycle chemistry and its influence on ozone and aerosol formation.
• Determine the fraction of urban volatile organic compound and nitrogen oxide emissions associated with emissions of carbon dioxide and methane from transportation, buildings, industry and landfills to quantify corresponding benefits of managing for both air quality and carbon emissions in urban settings.
• Investigate urban meteorology to better understand extreme heat impacts on urban air quality, urban heat islands, and the role of long-range transport versus local sources of air pollution.