Characteristics of ozone and particles in the near-surface atmosphere in urban area of the Yangtze River Delta, China
Bibliographic record
Abstract
Abstract. To improve the understanding of the interactions between particles and trace gases in a typical city of the YRD region, continuous measurements of particles and trace gases were made at an urban site in Nanjing during cold seasons in 2016 in this study. The average of particles, including black carbon (BC), PM2.5, and PM10 are 2.602 ± 1.720 μg/m3, 58.2 ± 36.8 μg/m3, and 86.3 ± 50.8 μg/m3, respectively, while the average of trace gases, which contain CO, O3, NOx, and NOy, are 850.9 ± 384.1, 37.7 ± 33.5, 23.5 ± 14.7, and 32.8 ± 22.3 ppb, respectively. Compared to National Ambient Air Quality Standards in China (NAAQS-CN), we found 48 days excess of PM2.5, 14 days excess of PM10, and 40 days excess of O3. The particles, CO, and nitrogen oxide concentrations shared a similar pattern of seasonality and diurnal cycles, which are different from O3. The former ones are all high in DJF and at rush hours, while the latter one had high loadings in the daytime, especially when the ultra violet (UV) was high. Correlation analysis reveals the formation of secondary aerosols, especially PM2.5, under high O3 and temperature conditions, and suggests a VOC-sensitive regime for photochemical production of O3 in urban Nanjing in cold seasons. Backward trajectory analysis suggests the prevailing winds in Nanjing were northerly and easterly during cold seasons in 2016. Air masses from eastern without passing through the urban agglomeration and those from northern without crossing BTH regions were cleaner, but air masses from local regions were more polluted in winter. A case study for a typical O3 and PM2.5 episode in December 2016 demonstrated that the episode was generally associated with regional transport and stable weather system. Air pollutants were mostly transported from the western areas with high emissions and weather conditions are controlled by anticyclone and high-pressure system in this region. This study further reveals the important effects of weather system and human activities on the environment in the YRD region, especially in the urban areas, and it's an urgent need for improving air quality in these areas.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".