Understanding of processes such as the direct radiative effect (Wang et al., 2008b), transport of ammonia in deep convection (Ge et al., 2018), aerosol These results, in turn, haveīeen used to inform and improve the results of CTMs, influencing our Species identified, cost, and personnel needs). Each method has different advantagesĪnd disadvantages (e.g., time resolution, sample preparation, range of Online ion chromatography (Talbot et al., 1997 Weber et al., 2001 Nie et al., 2010), and collection onto filters to be extracted and measured offline by Mass concentration, including by mass spectrometry (DeCarlo et al., 2006 Ĭanagaratna et al., 2007 Pratt and Prather, 2010 Froyd et al., 2019), There are numerous methods to quantify inorganic aerosol composition and Song et al., 2018) and remote regions (e.g., Hodzic et al., 2020), and theĬhemistry controlling the inorganic portion of aerosol is still not well The aerosol budget, both in polluted cities (e.g., Jimenez et al., 2009 Further, the inorganic portion of aerosol is an important fraction of Sodium) species, controls many of these impacts through the regulation ofĬharge balance, aerosol pH, and aerosol liquid water concentration (Guo etĪl., 2015, 2018 Hennigan et al., 2015 Nguyen et al., 2016 Pye et al., 2020). The inorganic portion of aerosol, which includesīoth volatile (e.g., nitrate, ammonium) and nonvolatile (e.g., calcium, Necessary to understand these impacts and to constrain and improve chemical Measurements of chemical composition and aerosol mass concentration are (Meskhidze et al., 2003 Abbatt et al., 2006 Seinfeld and Pandis, 2006 Visibility, climate, cloud formation and lifetime, and atmospheric chemistry Particulate matter (PM), or aerosol, impacts human health, ecosystem health, Finally, a more meaningful limit of detection for University of New Hampshire Soluble Acidic Gases and Aerosol (SAGA) filters collected during airborne campaigns is ∼0.2 µg sm −3 of ammonium, which is substantially higher than the limit of detection of ion chromatography.Ī similar analysis should be conducted for filters that collect inorganicĪerosol and do not have ammonia scrubbers and/or are handled in the presence This analysis enables guidelines for filter handling to reduce ammonia uptake. Measurements of gas-phase ammonia inside the cabin of the DC-8 show ammonia mixing ratios of 45☒0 ppbv, consistent with mixing ratios observed in other indoor environments. Using a gas uptake model with literature values for accommodation coefficients, we show that for ambient ammonia mixing ratios greater than 10 ppbv, the timescale for ammonia reacting with acidic aerosol on filter substrates is less than 30 s (typical filter handling time in the aircraft) for typical aerosol volume distributions. Another online measurement is consistent with the AMS in showing that the aerosol has lower ammonium-to-anion ratios than obtained by the filters. Versus an Aerodyne aerosol mass spectrometer (AMS). NASA DC-8 and NSF C-130 during six different aircraft campaigns, aĬonsistent, substantial difference in ammonium mass concentration andĪmmonium-to-anion ratios when comparing the aerosols collected on filters We show, using filters collected onboard the Turn affects our understanding of numerous physicochemical processes andĪerosol radiative properties. Any biases would impact the measured chemical composition, which in Method to analyze aerosols is to collect them onto filters and analyze theįilters offline however, biases in some chemical components are possibleĭue to changes in the accumulated particles during the handling of the Near emission sources to the most remote regions of the atmosphere. Measurements of the mass concentration and chemical speciation of aerosolsĪre important to investigate their chemical and physical processing from
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