Influences of emission sources and meteorology on aerosol chemistry in a polluted urban environment: results from DISCOVER-AQ California

Young, D. E.; Kim, Hwajin; Parworth, Caroline; Zhou, Shan; Zhang, Xiaolu; Cappa, C. D.; Seco, Roger; Kim, Saewung; Zhang, Qi

doi:10.5194/acp-16-5427-2016

Cited by 86 publications

(123 citation statements)

References 93 publications

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“…The morning peaks in HOA and BC during weekends might be influenced by the 9 highway next to the sampling site, where heavy traffic tended to occur during weekend morning 10 as residents drive out of SMA. A similar weekend effect on primary aerosol components was 11 observed in SMA during winter (Kim et al, 2017) and in urban and suburban sites in the U.S. as 12 well (Young et al, 2016;Zhou et al, 2016). 13…”

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confidence: 60%

“…8a). These major peaks and the overall picket 20 fence fragmentation pattern resulting from the CnH2n+1 + ions are typical features of the HOA 21 spectra reported in other studies and are due to the association of these aerosols with fossil fuel 22 combustion (e.g., Alfarra et al, 2007;Lanz et al, 2008;Sun et al, 2011b;Zhang et al, 2005a;Huang 23 et al, 2010;Morgan et al, 2010;Ng et al, 2011;Collier, 2015;Ge et al, 2012a;Kim et al, 24 2017;Young et al, 2016). In addition, strong correlations were observed between the time series 25 of HOA and the CnH2n+1 + and CnH2n-1 + ions, e.g., C3H7 + (r = 0.87), C4H7 + (r = 0.81), C4H9 + (r = 26 0.95), and C5H11 + (r = 0.96) (Fig.…”

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confidence: 85%

“…COA has been widely reported in urban areas with high population densities (e.g., He et 27 al., 2010;Huang et al, 2010;Mohr et al, 2012;Sun et al, 2011b;Young et al, 2016;Ge et al, 28 2012a;Wang et al, 2016b;Xu et al, 2014;Hayes et al, 2013). In this study, COA was found to 29 account for 22% of the total OA mass, higher than HOA (Fig.…”

Section: Cooking Oa (Coa) 26mentioning

confidence: 99%

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Influence of Intense secondary aerosol formation and long range transport on aerosol chemistry and properties in the Seoul Metropolitan Area during spring time: Results from KORUS-AQ

Kim¹,

Zhang²

2017

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22Non-refractory submicrometer particulate matter (NR-PM1) was measured in the Seoul 23Metropolitan Area (SMA), Korea, using an Aerodyne high-resolution time-of-flight aerosol mass 24 spectrometer (HR-ToF-AMS) from April 14 to June 15, 2016, as a part of the Korea-U.S. Air 25 Atmos. Chem. Phys. Discuss., https://doi.org/10. 5194/acp-2017-947 Manuscript under review for journal Atmos. Chem. Phys. Discussion started: 8 November 2017 c Author(s) 2017. CC BY 4.0 License. 2Quality Study (KORUS-AQ) campaign. This was the first highly time-resolved, real-time 1 measurement study of springtime aerosol in SMA and the results reveal valuable insights into the 2 sources and atmospheric processes that contribute to PM pollution in this region. 3The average concentration of submicrometer aerosol (PM1 = NR-PM1 + black carbon (BC)) 4 was 22.1 µg m -3 , which was composed of 44% organics, 20% sulfate, 17% nitrate, 12 % 5 ammonium, and 7 % BC. Organics had an average atomic oxygen-to-carbon (O/C) ratio of 0.49 6 and an average organic mass-to-carbon (OM/OC) ratio of 1.82. The concentration and composition 7 of PM1 varied dynamically due to the influences of different meteorological conditions, emission 8 sources, and air mass origins. Four distinct sources of OA were identified via positive matrix 9 factorization (PMF) analysis of the HR-ToF-AMS data: vehicle emissions represented by a 10 hydrocarbon like OA factor (HOA; O/C = 0.15; 17% of OA mass), cooking activities represented 11 by a cooking OA factor (COA; O/C = 0.19; 22% of OA mass), and secondary organic aerosol 12 (SOA) represented by a semi-volatile oxygenated OA factor (SV-OOA; O/C = 0.44; 27% of OA 13 mass) and a low volatility oxygenated OA factor (LV-OOA; O/C = 0.91; 34% of OA mass). 14 Our results indicate that air quality in SMA during KORUS-AQ was influenced strongly by 15 secondary aerosol formation with sulfate, nitrate, ammonium, SV-OOA, and LV-OOA together 16 accounting for 76% of the PM1 mass. In particular, high temperature, elevated ozone 17 concentrations, and photochemical reactions during daytime promoted the formation of SV-OOA, 18 LV-OOA and sulfate whereas nocturnal processing of nitrogen oxides and daytime photochemical 19 reactions promoted nitrate formation. In addition, gas-to-particle partitioning processes appeared 20 to have enhanced nighttime SV-OOA and nitrate formation. During a period of 4 days (from May 21 20 to May 23), LV-OOA was significantly enhanced and accounted for up to 41% of the PM1 22 mass. This intense LV-OOA formation event was associated with large enhancements of both 23 anthropogenic and biogenic VOCs (e.g., isoprene, toluene), high concentration of Ox (= O3 + NO2), 24 strong solar radiation, and stagnant conditions, suggesting that it was mainly driven by local 25 photochemical formation. We have also investigated the formation and evolution mechanisms of 26 severe haze episodes. Unlike the winter haze events which were mainly caused by intense local 27 emissions coupled with stagnant meteorological conditions,...

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confidence: 60%

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confidence: 85%

Section: Cooking Oa (Coa) 26mentioning

confidence: 99%

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Influence of Intense secondary aerosol formation and long range transport on aerosol chemistry and properties in the Seoul Metropolitan Area during spring time: Results from KORUS-AQ

Kim¹,

Zhang²

2017

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“…The common occurrence of regional particle pollution has acquired worldwide attention in the scientific community (Malm et al, 1994;Putaud et al, 2004;Chan and Yao, 2008) due to its adverse impacts on visibility (Singh and Dey, 2012;pollution include the emission of pollutants and weather conditions (Oanh and Leelasakultum, 2011;Young et al, 2016). Particle pollution in urban agglomerations is primarily attributed to very large amounts of the anthropogenic emissions of primary particles and their precursors (e.g., SO 2 , NO x , VOCs).…”

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confidence: 99%

Regional severe particle pollution and its association with synoptic weather patterns in the Yangtze River Delta region, China

et al. 2017

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Abstract. Regional air pollution is significantly associated with dominant weather systems. In this study, the relationship between the particle pollution over the Yangtze River Delta (YRD) region and weather patterns is investigated. First, the pollution characteristics of particles in the YRD are studied using in situ monitoring data (PM 2.5 and PM 10 ) in 16 cities and Terra/MODIS AOD (aerosol optical depth) products collected from December 2013 to November 2014. The results show that the regional mean value of AOD is high in the YRD, with an annual mean value of 0.71 ± 0.57. The annual mean particle concentrations in the cities of Jiangsu Province all exceed the national air quality standard. The pollution level is higher in inland areas, and the highest concentrations of PM 2.5 and PM 10 are 79 and 130 µg m −3 , respectively, in Nanjing. The PM 2.5 : PM 10 ratios are typically high, thus indicating that PM 2.5 is the overwhelmingly dominant particle pollutant in the YRD. The wintertime peak of particle concentrations is tightly linked to the increased emissions during the heating season as well as adverse meteorological conditions. Second, based on NCEP (National Center for Environmental Prediction) reanalysis data, synoptic weather classification is conducted and five typical synoptic patterns are objectively identified. Finally, the synthetic analysis of meteorological fields and backward trajectories are applied to further clarify how these patterns impact particle concentrations. It is demonstrated that air pollution is more or less influenced by high-pressure systems. The relative position of the YRD to the anti-cyclonic circulation exerts significant effects on the air quality of the YRD. The YRD is largely influenced by polluted air masses from the northern and the southern inland areas when it is located at the rear of the East Asian major trough. The significant downward motion of air masses results in stable weather conditions, thereby hindering the diffusion of air pollutants. Thus, this pattern is quite favorable for the accumulation of pollutants in the YRD, resulting in higher regional mean PM 10 (116.5 ± 66.9 µg m −3 ), PM 2.5 (75.9 ± 49.9 µg m −3 ), and AOD (0.74) values. Moreover, this pattern is also responsible for the occurrence of most large-scale regional PM 2.5 (70.4 %) and PM 10 (78.3 %) pollution episodes. High wind speed and clean marine air masses may also play important roles in the mitigation of pollution in the YRD. Especially when the clean marine air masses account for a large proportion of all trajectories (i.e., when the YRD is affected by the cyclonic system or oceanic circulation), the air in the YRD has a lesser chance of being polluted. The observed correlation between weather patterns and particle pollution can provide valuable insight into making decisions about pollution control and mitigation strategies.

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“…Previous observations in the SJV region have found a buildup of NH 4 NO 3 during pollution episodes (e.g., Chow et al, 2008). Approximately 30-80 % of the wintertime PM 2.5 mass in this region is ammonium nitrate (NH 4 NO 3 ), with a strong diurnal variability, and most other PM 2.5 is organic matter (Chow et al, 2006;Ge et al, 2012;Young et al, 2016;Parworth et al, 2017). During DISCOVER-AQ specifically, NO − 3 (p) was found to represent 28 % of non-refractory PM 1.0 (NR-PM 1 ; PM 1.0 , PM with aerodynamic diameter < 1 µm) mass on average ).…”

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Observational assessment of the role of nocturnal residual-layer chemistry in determining daytime surface particulate nitrate concentrations

et al. 2017

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Abstract. This study discusses an analysis of combined airborne and ground observations of particulate nitrate ) concentrations made during the wintertime DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically resolved observations relevant to Air Quality) study at one of the most polluted cities in the United States -Fresno, CA -in the San Joaquin Valley (SJV) and focuses on developing an understanding of the various processes that impact surface nitrate concentrations during pollution events. The results provide an explicit case-study illustration of how nighttime chemistry can influence daytime surface-level NO 3 (p) in the RL, along with daytime photochemical production, can contribute substantially to the buildup and sustaining of severe pollution episodes. The exceptionally shallow nocturnal boundary layer (NBL) heights characteristic of wintertime pollution events in the SJV intensify the importance of nocturnal production aloft in the residual layer to daytime surface concentrations. The observations also demonstrate that dynamics within the RL can influence the earlymorning vertical distribution of NO − 3 (p) , despite low wintertime wind speeds. This overnight reshaping of the vertical distribution above the city plays an important role in determining the net impact of nocturnal chemical production on local and regional surface-level NO − 3 (p) concentrations. Entrainment of clean free-tropospheric (FT) air into the boundary layer in the afternoon is identified as an important process that reduces surface-level NO − 3 (p) and limits buildup during pollution episodes. The influence of dry deposition of HNO 3 gas to the surface on daytime particulate nitrate concentrations is important but limited by an excess of ammonia in the region, which leads to only a small fraction of nitrate existing in the gas phase even during the warmer daytime. However, in the late afternoon, when diminishing solar heating leads to a rapid fall in the mixed boundary layer height (BLH), the impact of surface deposition is temporarily enhanced and can lead to a substantial decline in surface-level particulate nitrate concentrations; this enhanced deposition is quickly arrested by a decrease in surface temperature, whichPublished by Copernicus Publications on behalf of the European Geosciences Union. 14748 G. Prabhakar et al.: Particulate nitrate formation in the wintertime drops the gas-phase fraction to near zero. The overall importance of enhanced late-afternoon gas-phase loss to the multiday buildup of pollution events is limited by the very shallow nocturnal boundary layer. The case study here demonstrates that mixing down of NO − 3 (p) from the RL can contribute a majority of the surface-level NO − 3 (p) in the morning (here, ∼ 80 %), and a strong influence can persist into the afternoon even when photochemical production is maximum. The particular day-to-day contribution of aloft nocturnal NO − 3 (p) production to surface concentrations will depend on prevailing chemical and meteorological ...

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Influences of emission sources and meteorology on aerosol chemistry in a polluted urban environment: results from DISCOVER-AQ California

Cited by 86 publications

References 93 publications

Influence of Intense secondary aerosol formation and long range transport on aerosol chemistry and properties in the Seoul Metropolitan Area during spring time: Results from KORUS-AQ

Influence of Intense secondary aerosol formation and long range transport on aerosol chemistry and properties in the Seoul Metropolitan Area during spring time: Results from KORUS-AQ

Regional severe particle pollution and its association with synoptic weather patterns in the Yangtze River Delta region, China

Observational assessment of the role of nocturnal residual-layer chemistry in determining daytime surface particulate nitrate concentrations

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