Impact of Heatwaves and Declining NOx on Nocturnal Monoterpene Oxidation in the Urban Southeastern United States DOI Creative Commons

Nagappa Desai,

Aryiana Cemari Moore,

A. P. Mouat

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(17)

Published: Aug. 28, 2024

Abstract Nighttime oxidation of monoterpenes (MT) via the nitrate radical (NO 3 ) and ozone (O contributes to formation secondary organic aerosol (SOA). This study uses observations in Atlanta, Georgia from 2011 2022 quantify trends nighttime production NO (PNO O concentrations compare model outputs EPA's Air QUAlity TimE Series Project (EQUATES). We present urban‐suburban gradients their fractional importance (F) for MT oxidation. Both EQUATES show a decline PNO , with modeled declining faster than observations. Despite decreasing we find that continues dominate nocturnal boundary layer (NBL) (F NO3 = 60%) 2017, 2021, 2022, which is consistent 80%) 2013 2019. contrasts an anticipated F based on prior residual layer, where dominant oxidant. Using two case studies heatwaves summer extreme heat events can increase leading short lifetimes (<1 hr) high gas‐phase production. Regardless presence heatwaves, our findings suggest sustained urban SE US under x emissions, highlight need improved representation chemistry‐transport models additional along rural gradients.

Language: Английский

Comment on egusphere-2024-3694 DOI Creative Commons
Hans D. Osthoff

Published: Jan. 8, 2025

Abstract. Measurement of total peroxy nitrates (∑PNs) and alkyl (∑ANs) by instruments that use thermal dissociation (TD) inlets to convert the organic nitrate detectable NO2 may suffer from systematic bias (both positive negative) resulting unwanted secondary chemistry in heated inlets. Here we review sources methods used reduce it and/or correct for report new experiments using (for first time) atmospherically relevant, unsaturated, biogenic as well two different peroxyacetyl (PAN) sources. We show commonly commercial C3-alkyl-nitrate (isopropyl nitrate, IPN) inlet characterising ANs is not appropriate real-air samples contain longer chain nitrates. generated NO3-induced oxidation limonene are strongly positively biased presence NO. By detecting NOX rather than NO2, provide a simple solution avoid caused conversion NO primary radicals complex degradation long-chain, air at TD-temperatures. also photochemical source PAN characterise TD-inlets can result much stronger apparent diffusion synthesised (“pure”) similar mixing ratios. This explained thermally labile trace gases such peracetic acid (CH3C(O)OOH) hydrogen peroxide (H2O2).

Language: Английский

Citations

0
Gas-Phase Nitrate Radical Production Using Irradiated Ceric Ammonium Nitrate: Insights into Secondary Organic Aerosol Formation from Biogenic and Biomass Burning Precursors DOI
Andrew T. Lambe, Chase K. Glenn, Anita M. Avery

et al.

ACS Earth and Space Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 19, 2025

The importance of nitrate radicals (NO3) as an atmospheric oxidant is well-established. For decades, laboratory studies multiphase NO3 chemistry have used the same methods – either NO2 + O3 reactions or N2O5 thermal decomposition to generate it occurs in atmosphere. These methods, however, come with limitations, especially for N2O5, which must be produced and stored under cold dry conditions until its use. Recently, we developed a new photolytic source gas-phase by irradiating aqueous solutions ceric ammonium nitric acid. In this study, adapted method maintain stable concentrations over 24 h. We applied oxidation flow reactor (OFR) experiments measure yield chemical composition oxygenated volatile organic compounds (OVOCs) secondary aerosol (SOA) formed from (VOCs) emitted biogenic sources (isoprene, β-pinene, limonene, β-caryophyllene) biomass burning (phenol, guaiacol, syringol). SOA yields elemental ratios were typically within factor 2 10%, respectively, those obtained using conventional sources. Maximum our ranged 0.02 (isoprene/NO3) 0.96 (β-caryophyllene/NO3). highest oxygen-to-carbon (O/C) 0.48 (β-caryophyllene/NO3) 1.61 (syringol/NO3). Additionally, characterized novel condensed-phase products syringol/NO3 reactions. Overall, use irradiated cerium may enable more widespread NO3-initiated oxidative aging, has been less explored compared that hydroxyl radical chemistry.

Language: Английский

Citations

0
Influence of ambient NO and NO2 on the quantification of total peroxy nitrates (ΣPNs) and total alkyl nitrates (ΣANs) by thermal dissociation cavity ring-down spectroscopy (TD-CRDS) DOI Creative Commons

Laura Wüst,

Patrick Dewald,

Gunther N. T. E. Türk

et al.

Atmospheric measurement techniques, Journal Year: 2025, Volume and Issue: 18(8), P. 1943 - 1959

Published: April 30, 2025

Abstract. Measurement of total peroxy nitrates (ΣPNs) and alkyl (ΣANs) by instruments that use thermal dissociation (TD) inlets to convert the organic nitrate detectable NO2 may suffer from systematic bias (both positive negative) resulting unwanted secondary chemistry in heated inlets. Here we review sources methods used reduce it and/or correct for report new experiments using (for first time) atmospherically relevant, unsaturated, biogenic as well two different peroxyacetyl (PAN) sources. We show commonly commercial C3 (isopropyl nitrate, IPN) characterising ANs is not appropriate real-air samples contain longer-chain nitrates. Mixing ratios generated NO3-induced oxidation limonene are strongly positively biased presence NO. By detecting NOx rather than NO2, provide a simple solution avoid caused conversion NO primary radicals complex degradation long-chain, air at TD temperatures. also photochemical source PAN characterise can result much stronger apparent diffusion synthesised (“pure”) similar mixing ratios, especially if high acetone concentrations (and thus radical concentrations) involved. This explained thermally labile trace gases such peracetic acid (CH3C(O)OOH) hydrogen peroxide (H2O2).

Language: Английский

Citations

0
Insights Into Formation and Aging of Secondary Organic Aerosol From Oxidation Flow Reactors: A Review DOI
Zijun Zhang,

Weiqi Xu,

Andrew T. Lambe

et al.

Current Pollution Reports, Journal Year: 2024, Volume and Issue: 10(3), P. 387 - 400

Published: April 16, 2024

Language: Английский

Citations

3
Impact of Heatwaves and Declining NOx on Nocturnal Monoterpene Oxidation in the Urban Southeastern United States DOI Creative Commons

Nagappa Desai,

Aryiana Cemari Moore,

A. P. Mouat

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(17)

Published: Aug. 28, 2024

Abstract Nighttime oxidation of monoterpenes (MT) via the nitrate radical (NO 3 ) and ozone (O contributes to formation secondary organic aerosol (SOA). This study uses observations in Atlanta, Georgia from 2011 2022 quantify trends nighttime production NO (PNO O concentrations compare model outputs EPA's Air QUAlity TimE Series Project (EQUATES). We present urban‐suburban gradients their fractional importance (F) for MT oxidation. Both EQUATES show a decline PNO , with modeled declining faster than observations. Despite decreasing we find that continues dominate nocturnal boundary layer (NBL) (F NO3 = 60%) 2017, 2021, 2022, which is consistent 80%) 2013 2019. contrasts an anticipated F based on prior residual layer, where dominant oxidant. Using two case studies heatwaves summer extreme heat events can increase leading short lifetimes (<1 hr) high gas‐phase production. Regardless presence heatwaves, our findings suggest sustained urban SE US under x emissions, highlight need improved representation chemistry‐transport models additional along rural gradients.

Language: Английский

Citations

0