2012 Progress Report: Assessing The Synergistic Impact Of Anthropogenic And Biogenic Emissions On Air Pollution Using Novel High-Sensitivity, Real-Time Monitors For Fundamental Carbonyls
EPA Grant Number:
Assessing The Synergistic Impact Of Anthropogenic And Biogenic Emissions On Air Pollution Using Novel High-Sensitivity, Real-Time Monitors For Fundamental Carbonyls
Keutsch, Frank N
University of Wisconsin - Madison
EPA Project Officer:
February 1, 2012 through
January 31, 2015
(Extended to January 31, 2016)
Project Period Covered by this Report:
February 1, 2012 through January 31,2013
Developing the Next Generation of Air Quality Measurement Technology (2011)
Air Quality and Air Toxics
The goal of this project is to demonstrate instrumentation that will allow the use of novel high time resolution monitoring data sets as new metrics to determine the contribution of anthropogenic and biogenic emissions to ozone and organic aerosol (PM). We will demonstrate that the proposed novel instrumentation can obtain long-term, low-maintenance and accurate measurements of key carbonyl-containing compounds such as formaldehyde and glyoxal, consistent with the requirements for instrumentation employed in monitoring networks. The project will validate this approach by collecting a year-long dataset at the Horicon National Core Monitoring Station, a rural site in Wisconsin that is part of the EPA Region 5 Ambient Monitoring Network. An objective of this work is to develop the ratio and absolute concentration of monitored glyoxal/formaldehyde as a metric of the contribution of biogenic and anthropogenic volatile organic compounds (VOCs) to atmospheric oxidation. This metric will allow distinction between the direct contribution of anthropogenic VOCs and the anthropogenic impact on biogenic VOC oxidation (resulting O3 and PM via NOx), an emerging issue in air quality control, in particular for PM. In addition, these data will be compared with WRF-CMAQ model output to evaluate and improve the representation of atmospheric oxidative chemistry in models, thereby helping to provide strategies to control air quality related to O3 and PM.
In year 1 of the project, instrument construction, testing, calibration and intercomparison were conducted as well as advances of a chemical box model and preparation for year-long deployment to the Horicon site in Wisconsin. The activities conducted in year 1 of the project can be summarized into four major thrusts, which all focus on the development and evaluation of our instrumentation and measurements in preparation for the application to the novel, year-long measurements that are central to the proposed use of the carbonyl measurements for determination of the anthropogenic influence on rural secondary pollutant formation. Specifically, the following tasks were conducted in year 1:
(1) Assembly of monitoring instrumentation: Assembly of the formaldehyde fiber laser-induced fluorescence instrument and glyoxal laser-induced phosphorescence instrument was completed and both instruments were extensively tested; these tasks correspond to a major part of the tasks conducted in the first year, providing the novel monitoring instruments that are central to the proposed approach of using the measured carbonyls as metrics for assessing the synergistic impact of anthropogenic and biogenic emissions on air pollution. At the heart of both instruments are novel compact solid-state lasers that replace bulkier, open-path, high power-usage, and high maintenance traditional lasers.
(2) Instrument upgrades based on initial testing of the formaldehyde fiber laser-induced fluorescence instrument: Tests conducted at UW-Madison and as part of the instrument intercomparison (see 3 below) enabled a number of improvements aimed specifically at increasing the robustness of the instrument while maintaining ultra-high sensitivity and fast time response, all of which are central to the long-term autonomous monitoring that presents a critical aspect of the novelty proposed in this work. The advances included upgrade of flow and pressure control hardware and software; upgrade of instrument control software and data acquisition hardware/electronics for faster and remote operation as well as design/construction of a more robust detection cell and automated calibrations.
(3) Intercomparison of formaldehyde fiber laser-induced fluorescence instrument with state-of-the-art Hantzsch instrument confirmed the excellent performance of our autonomous instrument, making it ideally suited for the long-term, continuous and high-time resolution and high sensitivity formaldehyde measurements. The agreement between the lower time resolution Hantzsch instrument and our instrument was very good (within the instrument uncertainties at all times); the intercomparison is a central part of our quality assurance/control protocol.
(4) Advances in the chemical box model that will be applied by the Keutsch Group to the Horicon data. The box model mechanism was upgraded to allow integration of a number of recently proposed reaction schemes involving oxidative chemistry of VOCs and production of oxidation products (e.g., carbonyls). The model was tested and represents a state-of-the-art chemical one-dimensional (vertical) model. We will apply this model to the Horicon data to provide complementary information to the CMAQ models that will be provided by our collaborators.
The focus of year 2 will be continuous, long-term, fast (high time-resolution) and high precision measurements of two important carbonyls, formaldehyde (a toxic air pollutant) and glyoxal at the Horicon site in Wisconsin. This effort will contain extensive evaluation of the long-term behavior of the monitoring instruments with respect to sensitivity, accuracy and overall instrument performance. Towards the end of year 2, we expect to start addressing central scientific questions of evaluating anthropogenic influence on rural photochemistry using the novel data sets. During the second year, we will also collaborate with CMAQ modeling groups. Data will be made available to interested partners.
No journal articles submitted with this report: View all 2 publications for this project
Formaldehyde, secondary pollutant formation, ozone, anthropogenic influence, toxic air pollutants, secondary organic aerosol
Progress and Final Reports:
2013 Progress Report
2014 Progress Report