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Elevated levels of OH observed in haze events during wintertime in central Beijing

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Elevated levels of OH observed in haze events during wintertime in central Beijing. / Slater, Eloise; Whalley, Lisa K.; Woodward-Massey, Robert et al.
In: Atmospheric Chemistry and Physics , Vol. 20, 02.12.2020, p. 14847-14871.

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Harvard

Slater, E, Whalley, LK, Woodward-Massey, R, Ye, C, Lee, JD, Squires, F, Hopkins, JR, Dunmore, RE, Shaw, M, Hamilton, JF, Lewis, AC, Crilley, LR, Kramer, LJ, Bloss, WJ, Vu, T, Sun, Y, Xu, W, Yue, S, Ren, L, Acton, WJF, Hewitt, CN, Wang, X, Fu, P & Heard, DE 2020, 'Elevated levels of OH observed in haze events during wintertime in central Beijing', Atmospheric Chemistry and Physics , vol. 20, pp. 14847-14871. https://doi.org/10.5194/acp-20-14847-2020, https://doi.org/https://acp.copernicus.org/articles/20/14847/2020/

APA

Slater, E., Whalley, L. K., Woodward-Massey, R., Ye, C., Lee, J. D., Squires, F., Hopkins, J. R., Dunmore, R. E., Shaw, M., Hamilton, J. F., Lewis, A. C., Crilley, L. R., Kramer, L. J., Bloss, W. J., Vu, T., Sun, Y., Xu, W., Yue, S., Ren, L., ... Heard, D. E. (2020). Elevated levels of OH observed in haze events during wintertime in central Beijing. Atmospheric Chemistry and Physics , 20, 14847-14871. https://doi.org/10.5194/acp-20-14847-2020, https://doi.org/https://acp.copernicus.org/articles/20/14847/2020/

Vancouver

Slater E, Whalley LK, Woodward-Massey R, Ye C, Lee JD, Squires F et al. Elevated levels of OH observed in haze events during wintertime in central Beijing. Atmospheric Chemistry and Physics . 2020 Dec 2;20:14847-14871. doi: 10.5194/acp-20-14847-2020, https://acp.copernicus.org/articles/20/14847/2020/

Author

Slater, Eloise ; Whalley, Lisa K. ; Woodward-Massey, Robert et al. / Elevated levels of OH observed in haze events during wintertime in central Beijing. In: Atmospheric Chemistry and Physics . 2020 ; Vol. 20. pp. 14847-14871.

Bibtex

@article{4ee265a331a54adba09dcbb221321811,
title = "Elevated levels of OH observed in haze events during wintertime in central Beijing",
abstract = "Wintertime in situ measurements of OH, HO2 and RO2 radicals and OH reactivity were made in central Beijing during November and December 2016. Exceptionally elevated NO was observed on occasions, up to ∼250 ppbv. The daily maximum mixing ratios for radical species varied significantly day-to-day over the ranges 1–8×106 cm−3 (OH), 0.2–1.5×108 cm−3 (HO2) and 0.3–2.5×108 cm−3 (RO2). Averaged over the full observation period, the mean daytime peak in radicals was 2.7×106, 0.39×108 and 0.88×108 cm−3 for OH, HO2 and total RO2, respectively. The main daytime source of new radicals via initiation processes (primary production) was the photolysis of HONO (∼83 %), and the dominant termination pathways were the reactions of OH with NO and NO2, particularly under polluted haze conditions. The Master Chemical Mechanism (MCM) v3.3.1 operating within a box model was used to simulate the concentrations of OH, HO2 and RO2. The model underpredicted OH, HO2 and RO2, especially when NO mixing ratios were high (above 6 ppbv). The observation-to-model ratio of OH, HO2 and RO2 increased from ∼1 (for all radicals) at 3 ppbv of NO to a factor of ∼3, ∼20 and ∼91 for OH, HO2 and RO2, respectively, at ∼200 ppbv of NO. The significant underprediction of radical concentrations by the MCM suggests a deficiency in the representation of gas-phase chemistry at high NOx. The OH concentrations were surprisingly similar (within 20 % during the day) in and outside of haze events, despite j(O1D) decreasing by 50 % during haze periods. These observations provide strong evidence that gas-phase oxidation by OH can continue to generate secondary pollutants even under high-pollution episodes, despite the reduction in photolysis rates within haze.",
author = "Eloise Slater and Whalley, {Lisa K.} and Robert Woodward-Massey and Chunxiang Ye and Lee, {James D.} and Freja Squires and Hopkins, {James R.} and Dunmore, {Rachel E.} and Marvin Shaw and Hamilton, {Jacqueline F.} and Lewis, {Alastair C.} and Crilley, {Leigh R.} and Kramer, {Louisa J.} and Bloss, {William J.} and Tuan Vu and Yele Sun and Weiqi Xu and Siyao Yue and Lujie Ren and Acton, {W. Joe F.} and Hewitt, {C N} and Xinming Wang and Pingqing Fu and Heard, {Dwayne E.}",
year = "2020",
month = dec,
day = "2",
doi = "10.5194/acp-20-14847-2020",
language = "English",
volume = "20",
pages = "14847--14871",
journal = "Atmospheric Chemistry and Physics ",
issn = "1680-7316",
publisher = "Copernicus GmbH (Copernicus Publications) on behalf of the European Geosciences Union (EGU)",

}

RIS

TY - JOUR

T1 - Elevated levels of OH observed in haze events during wintertime in central Beijing

AU - Slater, Eloise

AU - Whalley, Lisa K.

AU - Woodward-Massey, Robert

AU - Ye, Chunxiang

AU - Lee, James D.

AU - Squires, Freja

AU - Hopkins, James R.

AU - Dunmore, Rachel E.

AU - Shaw, Marvin

AU - Hamilton, Jacqueline F.

AU - Lewis, Alastair C.

AU - Crilley, Leigh R.

AU - Kramer, Louisa J.

AU - Bloss, William J.

AU - Vu, Tuan

AU - Sun, Yele

AU - Xu, Weiqi

AU - Yue, Siyao

AU - Ren, Lujie

AU - Acton, W. Joe F.

AU - Hewitt, C N

AU - Wang, Xinming

AU - Fu, Pingqing

AU - Heard, Dwayne E.

PY - 2020/12/2

Y1 - 2020/12/2

N2 - Wintertime in situ measurements of OH, HO2 and RO2 radicals and OH reactivity were made in central Beijing during November and December 2016. Exceptionally elevated NO was observed on occasions, up to ∼250 ppbv. The daily maximum mixing ratios for radical species varied significantly day-to-day over the ranges 1–8×106 cm−3 (OH), 0.2–1.5×108 cm−3 (HO2) and 0.3–2.5×108 cm−3 (RO2). Averaged over the full observation period, the mean daytime peak in radicals was 2.7×106, 0.39×108 and 0.88×108 cm−3 for OH, HO2 and total RO2, respectively. The main daytime source of new radicals via initiation processes (primary production) was the photolysis of HONO (∼83 %), and the dominant termination pathways were the reactions of OH with NO and NO2, particularly under polluted haze conditions. The Master Chemical Mechanism (MCM) v3.3.1 operating within a box model was used to simulate the concentrations of OH, HO2 and RO2. The model underpredicted OH, HO2 and RO2, especially when NO mixing ratios were high (above 6 ppbv). The observation-to-model ratio of OH, HO2 and RO2 increased from ∼1 (for all radicals) at 3 ppbv of NO to a factor of ∼3, ∼20 and ∼91 for OH, HO2 and RO2, respectively, at ∼200 ppbv of NO. The significant underprediction of radical concentrations by the MCM suggests a deficiency in the representation of gas-phase chemistry at high NOx. The OH concentrations were surprisingly similar (within 20 % during the day) in and outside of haze events, despite j(O1D) decreasing by 50 % during haze periods. These observations provide strong evidence that gas-phase oxidation by OH can continue to generate secondary pollutants even under high-pollution episodes, despite the reduction in photolysis rates within haze.

AB - Wintertime in situ measurements of OH, HO2 and RO2 radicals and OH reactivity were made in central Beijing during November and December 2016. Exceptionally elevated NO was observed on occasions, up to ∼250 ppbv. The daily maximum mixing ratios for radical species varied significantly day-to-day over the ranges 1–8×106 cm−3 (OH), 0.2–1.5×108 cm−3 (HO2) and 0.3–2.5×108 cm−3 (RO2). Averaged over the full observation period, the mean daytime peak in radicals was 2.7×106, 0.39×108 and 0.88×108 cm−3 for OH, HO2 and total RO2, respectively. The main daytime source of new radicals via initiation processes (primary production) was the photolysis of HONO (∼83 %), and the dominant termination pathways were the reactions of OH with NO and NO2, particularly under polluted haze conditions. The Master Chemical Mechanism (MCM) v3.3.1 operating within a box model was used to simulate the concentrations of OH, HO2 and RO2. The model underpredicted OH, HO2 and RO2, especially when NO mixing ratios were high (above 6 ppbv). The observation-to-model ratio of OH, HO2 and RO2 increased from ∼1 (for all radicals) at 3 ppbv of NO to a factor of ∼3, ∼20 and ∼91 for OH, HO2 and RO2, respectively, at ∼200 ppbv of NO. The significant underprediction of radical concentrations by the MCM suggests a deficiency in the representation of gas-phase chemistry at high NOx. The OH concentrations were surprisingly similar (within 20 % during the day) in and outside of haze events, despite j(O1D) decreasing by 50 % during haze periods. These observations provide strong evidence that gas-phase oxidation by OH can continue to generate secondary pollutants even under high-pollution episodes, despite the reduction in photolysis rates within haze.

U2 - 10.5194/acp-20-14847-2020

DO - 10.5194/acp-20-14847-2020

M3 - Journal article

VL - 20

SP - 14847

EP - 14871

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

SN - 1680-7316

ER -