The Third Annual Statewide. Atmospheric Chemistry as a Pollution Prevention Tool. Ray Wells, Ph.D. Air Team USAF Research Lab.

Transcription

1 The Third Annual Statewide Atmospheric Chemistry as a Pollution Prevention Tool Ray Wells, Ph.D. Air Team USAF Research Lab Session 10

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3 USING ATMOSPHERIC CHEMISTRY AS A DECISION TOOL Ray Wells, Sheryl Wyatt, Bill Bradley AFRL/MLQR Air Team Tyndall AFB, FL (850) ray.wells@nlq.afrl.af.mil AFRL/MLQR s Air Team is using unique innovative technologies to address P2. Emissions from operations have and will continue to be identified as a source of burden. Air Team s investigations characterizing formulation emission and exploring atmospheric transfonnations of oxygenated organic compound substitutes have demonstrated potential air quality improvements of new formulations and lead to the discovery of complex atmospheric transformation mechanisms. Both of these contributions can benefit DoD operations by minimizing regulatory burdens and constraints. Solvent substitution is being used as a tool by manufacturers of -coatings, paint strippers and cleaners in order to meet Department of Defense pollution prevention initiatives. The newly revised ozone (0,) and particulate matter (PM,,) regulations have also amplified the need to reformulate. Reformulations cannot meet the new demands of economic and environmental constraints without accurate air quality impact assessments. Currently, formulation selection is based on scant Material Safety Data Sheets (MSDS) data, but a material s composition does not necessarily describe its emissions. Therefore if only MSDS data were used, the assessment of a formulation s impact on air quality could have a large degree of uncertainty. AFRL/MLQRs Air Team has developed the capability to accurately assess air quality impacts by characterizing the volatile organic compound (VOC) emissions from complex formulations (coatings, coating strippers, cleaners, fuels). This capability has helped the Army, Joint Acquisition, Sustainment Pollution Prevention Activity (JASPPA), and the Air Force Research Laboratory s Materials Directorate to optimize formulation selection. New classes of compounds such as oxygenated organics (ethers, acetates, and alcohols) are popular substitutes for aromatic compounds like benzene or toluene, but current understanding of their air quality impact is limited. Investigating the atmospheric chemistry of this class of compounds contributes an important component to emissions assessments and minimizes use of chemicals generating unnecessary and harmful air pollution.

4 ~ mn AIR FORCE RESEARCH LABORATORY USING ATMOSPHERIC CHEMISTRY AS A DECISION TOOL 1. Introduce Air Team. 2. Communicate principles of atmospheric chemistry. 3. Highlight experimental results and challenges. Ray Wells AFRL/MLQR Air Team (850) ray.mllr@mlqafti.af.mil *- DoD Releases by Media, 1994 Land Water 1.31% 1.25% TEAM ACCOMPLISHMENTS Lab Director Project CRADA Tri-Service Projects 7 Publications 3 Technical Reports TEAM SKILLS Chemistry AtmosphenC. Analytical Kinetics -Meteorology Ray Wells, Ph.D. Capt. Leon Perkowski Mike Henley - B.S. Sheryl Wyatt - B.S. Bill Bradley - M.S. 15'94 Toxics Release Inventwy for the DoD Public Data RepOrt, March 7,1996 Emissions Systems Clean Air Act new regulations and guidance documents Eva po ratio- They impact our missions!

5 Collaboration Sources of Pollution GOAL: Characterize emissions Achieved by addressing: 1. What is being emitted? 2. What happens to emitted chemicals? Combustion Exhausts New substitutions affect these sources OH Radical 0, + - hv O(lD) + 0, O(1D) + H,O 2 OH RH + OH- NO, Radical R + H,O NO, + 0, - NO, + 0, NO, + NO, z== N205 RH +NO3 - R + HN03 Reaction Chamber Atmospheric Transformation Processes RH +OH. R + HZO R+0, R02 RO, NO NOz + RO NO; + hv NO-+ 0 O+O,+M - 0, + M RH + OH. + 20, - RO + H20+ 0, Experimental Methods I. Relative Rate Techniaue: Compare unknown atmospheric radical reaction rate to one that is known: 1) Reference + OH/NO,- Products 2) Unknown + OH/NO,- Products Dividing differential equations to remove OH/NO, concentration and time and integrating yields:

6 -- I m 5 O B = 0.1 a05 0 :y I,\ O\ l 0 3 References First Report 163 hour lifetin Hydroxyl Radical Rate Constants Rate constants and chemical structures are variable Compound/Struare b,,( lu~lm~mol~ulrls~)/lifetime (hr) I Experimental Methods Atmospheric Transformation Mechanism for MIB a. Product Identification and Yields: Unknown + OH/N03 -Products Must correct for transformation productlabnospheric radical reaction to determine yield: [Unknown] Air Quality Impact CONCLUSIONS Coating A Coating B MIL-P-23377F = 0.27 g 031g paint = 0.27 g 031g paint = 0.75 g 0,lg paint Regulations are relying on more detailed science Regulations are becoming more stringent Atmospheric Chemistry is a key strategy to maintaining performance while meeting regulations gram OJgram Daint = X (gram emitted VWgram paint)' Factor,