Details

Autor(en) / Beteiligte

• Le, Nhung H.
• Ly, Bich-Thuy
• Thai, Phong K.
• Pham, Gia-Huy
• Ngo, Ich-Hung
• Do, Van-Nguyet
• Le, Thuy T.
• Nhu, Luan V.
• Son, Ha Dang
• Nguyen, Yen-Lien T.
• Pham, Duong H.
• Vu, Tuan V.

Titel

Assessing the Impact of Traffic Emissions on Fine Particulate Matter and Carbon Monoxide Levels in Hanoi through COVID-19 Social Distancing Periods

Ist Teil von

• Aerosol and Air Quality Research, 2021-10, Vol.21 (10), p.210081

Ort / Verlag

Taoyuan City: 社團法人台灣氣膠研究學會

Erscheinungsjahr

2021

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Hanoi, Vietnam, is usually ranked as one of the most polluted capital cities in terms of air quality, particularly PM_(2.5). However, there has not been enough data to determine the main source of this pollution. In this study, we utilized the rare opportunity of the COVID-19 social distancing to assess the contribution of traffic emission to PM_(2.5) and CO levels when traffic volume was reduced significantly in Hanoi. Hourly PM_(2.5) and CO concentrations were measured from nine urban and traffic monitoring stations during pre-, soft, hard, and post-social distancing periods. As a result, we observed large reductions in both PM_(2.5) and CO levels during social distancing periods. PM_(2.5) concentrations were 14-18% lower during the social distancing than before this period, while CO concentrations had a more considerable drop by 28-41%. It is known that meteorological conditions can have significant effects on the ambient levels of air pollutants. To overcome this challenge, weather normalized concentrations of those pollutants were estimated using the random forest model, a machine learning technique. The normalized weather concentrations showed smaller reductions by 7-10% for PM_(2.5) and 5-11% for CO, indicating the presence of favorable weather conditions for better air quality during the social distancing period. In further analysis, the apparent improvement of air quality in Hanoi during the social distancing period was in line with reducing traffic emissions while emissions from coal-fired power plants remained relatively stable.