Notice bibliographique
Résumé
Fine particulate matter less than 2.5 microns (PM2.5) could exacerbate bronchitis and cardiac conditions.PM2.5 concentration has been globally increasing due to operation of power plants and vehicles.Recently, annual PM2.5 concentration in Seoul, Korea averaged 24.㎍ , higher than the World Health Organization (WHO)'s annual reference level of 20.0 ㎍[1].There is rising concern on urban tree planting to help reduce the level of atmospheric PM2.5 [2].However, little is known about PM2.5 reduction by urban trees in the city.The purpose of this study was to quantify annual PM2.5 reduction by street trees in Seoul and to suggest desirable planting and management strategies to improve effects of PM2.5 deposition.Data on street trees were collected on plots which were located using a stratified sampling method on aerial photographs with a scale 1:1,000 [3].Eight straight lines radiating from the center of the study city were drawn in eight different directions, and subsequently circles were drawn 40 cm apart.This study sampled a total of 50 points at which the circles and lines coincided.A survey plot for each point was established up to 80 m in length from the point and to building boundaries of both sidewalks in width.The number of samples was a compromise between the competing concerns for a large sample size and the availability of expense.Field-surveyed data included species, stem diameter, height, crown width, and density of street trees.These data were used to produce an average estimate per unit area on annual PM2.5 reduction by street trees.The PM2.5 reduction was quantified applying a dry deposition model [2,4] based on deposition velocity, total leaf area, and resuspension ratio by wind speed.Total PM2.5 reduction by street trees was computed using total street area in the study city.The structures of street trees in the study city were characterized by single-layered and single-aged planting.Mean stem diameter of street trees was 25.5 cm (at breast height of 1.2 m) and annual PM2.5 reduction per street tree averaged approximately 47.2 g/yr.Annual PM2.5 reduction per unit area by street trees was approximately 4.2 kg/ha/yr, and total PM2.5 reduction of the entire street area was about 32.8 t/yr.Total annual emissions of PM2.5 from energy consumption was about 1,300 t/yr in the study city [5].Street trees annually offset the total PM2.5 emissions by 2.5%.Thus, street trees played an important role in reducing the level of atmospheric PM2.5.This study suggested desirable planting and management strategies including multi-layered and multi-aged tree planting, supply of the space for normal crown and root growth, and avoidance of severe pruning.The results from this study are expected to contribute to internationally sharing the role and importance of urban trees in reducing PM2.5 concentration.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».