Unexpectedly High Levels of H₂O₂ Drive Sulfate Formation over the Residual Layer in Beijing

Environmental Science & Technology, Год журнала: 2025, Номер unknown

Опубликована: Фев. 2, 2025

Hydrogen peroxide (H2O2) plays a key role in atmospheric chemistry, but knowledge of its variation, sources, and impact on sulfate formation remains incomplete, especially the urban boundary layer aloft. Here, we conducted field campaign with measurements H2O2 related species at tower-based site (∼528 m above ground surface) Beijing spring 2022. The observed hourly concentration reached up to 21.2 ppbv an average value 3.4 ± 3.7 during entire observation period, which was higher than values from previous observations throughout world. budget revealed that two known sources (self-reaction HO2 radicals ozonolysis alkenes) could not account for significant H2O2, leading considerable unknown source strength (∼0.14–0.53 h–1) noon after sunset. Based levoglucosan signal, distribution fire points, backward trajectories, biomass burning emissions southwest (e.g., North China Plain) were found contribute greatly formation. Besides, photochemical aging PM2.5 might also have potential production noon. unexpectedly high concentrations aloft made vital contribution (0.2–1.1 μg m–3 h–1), be transported surface turbulent mixing. Our findings provide improved understanding chemistry megacity, as well

Язык: Английский

---

High-Resolution Remote Sensing of the Gradient Richardson Number in a Megacity Boundary Layer

Remote Sensing, Год журнала: 2024, Номер 16(6), С. 1075 - 1075

Опубликована: Март 19, 2024

The Gradient Richardson Number (Ri) is an important parameter for appraising the stability and turbulence exchange at atmospheric boundary layer (ABL). However, high-resolution measurements of Ri profiles are rarely reported, especially in megacities. In this study, a Doppler wind lidar microwave radiometer were simultaneously utilized to measure 2 km vertical profile downtown Beijing. These verified have high accuracy compared with observations from 325 m meteorological tower, root-mean-square errors (RMSEs) less than 1.66 K, 7.9%, 1.45 m/s temperature, relative humidity, speed (WS) all altitudes corresponding Pearson correlation coefficients (R) 0.97, 0.93, 0.81. inter-comparisons different spatial (25 m, 50 100 m) temporal resolutions (1 min, 30 1 h) form 3 × resolution matrix Ri, which h overestimates intensity active area turbulence. value retrieved data these by half as it misidentifies height stable near surface. There significant differences between min 25 (defined standard Ri), rest other resolutions), RMSE > R < 0.8. difference increases elevations, results frequent weather processes or water-vapor blocking higher altitudes. reveal that 500 daytime unstable, 0, while neutral, 0 0.25, night-time 200 400 m. atmosphere above ABL megacity rather stable, whereas below ABL, neutral due drastic changes WS temperature affected topography surface friction.

Язык: Английский

---

The interaction of atmospheric boundary layer and PM pollution in Mongolian Plateau: Implication for the threshold control strategy

Atmospheric Research, Год журнала: 2025, Номер unknown, С. 107937 - 107937

Опубликована: Янв. 1, 2025

Язык: Английский

---

The Aerosol Optical Properties over a Desert Industrial City Wuhai, Northwest China, During the 3-Year COVID-19 Pandemic

Sustainability, Год журнала: 2025, Номер 17(9), С. 3937 - 3937

Опубликована: Апрель 27, 2025

Aerosol optical depth (AOD) data from 2020 to 2022 during the COVID-19 pandemic in a typical desert industrial city, Wuhai, was analyzed investigate aerosol properties, origins of different types aerosols, and impacts lockdown on pollution. Results show that annual AOD (500 nm) Ångström exponent α were 0.36 ± 0.12 0.75 0.22 2020, 0.30 0.14 2021, 0.28 0.09 0.74 0.19 2022, respectively, representing slightly polluted environment characterized by mixture coarse-mode dust aerosols fine-mode anthropogenic aerosols. Seasonal analysis reveals highest primarily occurred spring due frequent events, while lowest observed winter. Potential Source Contribution Function (PSCF) identified Alxa Desert as major potential source entire year, mining activities northern Ningxia southern Inner Mongolia also important contributors, particularly outside winter season. The prevailing wind direction Wuhai northwest (NW-quadrant), originating depopulated or Gobi area, accounting for 85.11% spring, 61.45% summer, 68.09% autumn, 100% remaining air masses came southeastern (SE-quadrant) densely populated areas. Despite dominance NW flows, SE resulted 0.47 0.24 0.38 0.23 0.32 0.17 with corresponding finest particle sizes 0.83 0.31, 0.91 0.30, 1.02 α. This suggests influence remains significant even under strict control measures lockdown. In winter, contributed pollution 0.49 0.39 size 0.90 (α), likely associated coal/straw burning heating. addition, particles leading moderate ranged around 0.2–0.25 µm, fine persists throughout year.

Язык: Английский

---

Study of boundary layer parameterization simulation uncertainties of sand-dust storm windfield using high-resolution three-dimensional Doppler wind lidar data

Atmospheric Research, Год журнала: 2024, Номер 306, С. 107456 - 107456

Опубликована: Май 10, 2024

Язык: Английский

---

Multi-model revealing the driving factors of black carbon pollution in Hohhot, the largest city on the Mongolian plateau

Urban Climate, Год журнала: 2024, Номер 56, С. 102055 - 102055

Опубликована: Июль 1, 2024

Язык: Английский

---