Generation and dissemination of climate/environmental relevant gas and aerosol standards Hanspeter Andres

Agenda Introduction Climate relevant gas standards current status and ideas for future research activities Environmental relevant aerosol standards Summary METAS 08.04.2019

Introduction Identified gas metrology needs Physical and chemical properties of the atmosphere, i.e. its physical state, the chemical composition as well as the essential transport processes by means of optical remote sensing methodologies and local “in situ” sensing techniques, focusing on establishing traceability in measurements and the evaluation of uncertainties, for important atmospheric constituents and their precursors, reaction partners and isotopologues of the atmospheric Water-, Ozone-, Nitrogen-, Carbon- and Sulfur-cycles, and other reactive climate change relevant gaseous components. METAS 08.04.2019

Introduction Identified aerosol metrology needs Traceable measurements are required for size number concentration mass surface area for particles from a few nm up to several μm, especially at low concentrations and for nanoparticles of different type and morphology. The chemical composition of particulates remains a key issue for air quality. METAS 08.04.2019

Climate-relevant gas standards generation of SI-traceable halocarbons Dynamic generation of reference gas mixtures with a coated magnetic suspension balance Reference gas mixtures in the nmol/mol range collected in pressurized cylinders by cryotrapping Scale comparison measurements using Medusa-GC-MS technology (Empa). 135 km I II III METAS 08.04.2019

Climate-relevant gas standards halocarbon observation networks NOAA/ESRL Halocarbon Surface and Aircraft Sampling Network AGAGE Continuous Halocarbon in-situ Sampling Network METAS 08.04.2019

Climate-relevant gas standards motivation extending work on halocarbons Contribution of halocarbons to climate change is increasing Current scale NOAA and AGAGE scales focus on precision not on SI-traceability no WMO CCL for halocarbons Legend: HFOs: 4th generation halocarbons HFCs: 3rd generation halocarbons HCFCs: 2nd generation halocarbons CFCs: 1st generation halocarbons Velders et al., Science (2012) METAS 08.04.2019

Climate-relevant gas standards HFCs – to be banned as well Nature, 12. November 2015 “The world took a step in the right direction in the early hours of 6 November [2015]. Meeting in Dubai, 195 governments decided to pull the management of hydrofluorocarbons (HFCs) under the umbrella of the Montreal Protocol. [...] Unfortunately, some governments still seem to be hedging their bets. In particular, India, Saudi Arabia and Kuwait pushed to delay consideration of detailed amendments to the Montreal Protocol until next year. [...] METAS 08.04.2019

Environmental aerosol standards current aerosol calibration sources Single-component calibration aerosols Generators Aerosol properties already established at METAS Particle size: from a few nm to a few μm Oil droplets Electrospray Number concentration: how many particles /cm3? Salt particles Chemical composition: Inorganic, organic? Does it contain trace metals? Atomiser Mass concentration: μg of particulates pro m3 Combustion particles Particle morphology: spherical, rod like, nanotubes? miniCAST METAS 08.04.2019

Environmental aerosol standards aerosol characterisatioin Multi-component calibration aerosols Generators Aerosol properties Particle size: from a few nm to a few μm Oil droplets Electrospray Number concentration: how many particles /cm3? Salt particles Tunable Chemical composition: Inorganic, organic? Does it contain trace metals? Atomiser Mass concentration: μg of particulates pro m3 Combustion particles Particle morphology: spherical, rod like, nanotubes? miniCAST METAS 08.04.2019

Environmental aerosol standards composition of a representative ambient aerosol Dust particles Combustion particles Organic particles Salts Bioaerosols Si Al Ca Fe Mg K etc. Elemental Carbon + Organic Matter Isoprene Terpenes Alcohols Aldehydes Ketones etc NO3- NH4+ SO42- Na+ Mg+ Cl- etc. Viruses Bacteria Fungi Pollen EC12.6% Unknown 13.4% Trace elements Trace ele- ments 13.8% OM 26.5% Humidity: 30%-80% Mineral dust 8.2% Sulfate (SO42-) 7.4% METAS 08.04.2019 Ammonium (NH4+) 5.2% Nitrate (NO3-) 12.8%

Environmental aerosol standards ambient air generator The mixing chamber will be equipped with: Inlets for various primary aerosol species Two-stage dilution air injection allowing for turbulent mixing Humidity and temperature control for aerosol processing Isokinetic sampling ports Analysis: Chromatography Laser-induced incandescence Particle counting Particle sizing Mixing chamber chemical to optical physical ✓ ✓ METAS 08.04.2019

Environmental aerosol standards calibration of automatic PM-monitors Particle mass concentration is the most important particle metric for air quality Ambient threshold values for PM2.5 and PM10 have been established in Europe (EU Air Quality Directive 2008/50/EC) and worldwide However, no reference aerosol exists for calibrating commercial PM- measuring instruments Comparison to reference method with field measurements at least twice a year at 2 different sites (time-consuming/expensive procedures with high uncertainties) Ambient air generators will allow calibrations in the lab Automatic PM-instruments: based on different measurement techniques different sampling inlet TEOM (Tapered Element Oscillating Microbalance) Light scattering Beta-absorption METAS 08.04.2019

Summary Climate-relevant gas standards: continue and extend work on dynamic generation and crypotrapping of reactive and sub-ppt gas species; i.e. banned climate relevant gas components CFCs, HCFCs and HFCs under the 'Montreal Protocol‘ in collaboration with Empa Environmental aerosol standard: develop an ambient aerosol source with tunable parameters such as particle size, number concentration, EC/OC ratio, PAHs and salt content for easy calibration of widely used PM monitors Ideas for WPs and not entire JRPs, METAS/Empa are not entitled to coordinate METAS 08.04.2019

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