Casallas Alejandro, Castillo-Camacho Maria Paula, Guevara-Luna Marco Andrés, González Yuri, Sanchez Edwin, Belalcazar Luis Carlos
Earth System Physics, Abdus Salam International Centre for Theoretical Physics, Trieste, Italy; Escuela de Ciencias Exactas e Ingeniería, Universidad Sergio Arboleda, Bogotá, Colombia.
Departamento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Bogotá, Colombia.
Sci Total Environ. 2022 Dec 15;852:158504. doi: 10.1016/j.scitotenv.2022.158504. Epub 2022 Sep 6.
This paper analyzes the spatio-temporal variations, and exceedances of the PM concentrations in Northwestern South America at different scales to assess the implemented policies and identify the involved phenomena. Through reanalysis and ground-based data, we found that high PM levels in most cities of the region are caused by wildfires and local emissions, including the capital cities of Venezuela, Ecuador, Colombia, and Panamá. In-situ measurements suggest that the majority of the cities comply with the local but not with the WHO guidelines, indicating that local annual limits should be more restrictive. Two peaks in the daily variations of PM (related to vehicle emissions) and also a steeper decrease around noon (associated with an increase in wind speed and in the boundary layer height) were identified. The trend-analysis shows that Bogotá and Medellín have a decreasing PM annual-trend (between -0.8μgm and -1.7μgm) that corresponds to effective policies. In contrast, Cali has a positive annual-trend (0.8μgm) most likely because of Short-Range Transport produced by a northerly-flow from a highly polluted neighboring city, which also affects Cali's PM diurnal cycle, or by local-dynamics. The exceedances show that the policies are working on an annual but not at a daily time-scale. These results serve as a first input for additional studies, with the aim of gaining a better understanding of the contaminant before adapting current policies or implementing new policies and measures that need to include a joint international, regional, and inter-city efforts regarding pollution transport.
本文分析了南美洲西北部不同尺度下颗粒物（PM）浓度的时空变化及超标情况，以评估已实施的政策并识别相关现象。通过再分析和地面数据，我们发现该地区大多数城市的高PM水平是由野火和本地排放造成的，包括委内瑞拉、厄瓜多尔、哥伦比亚和巴拿马的首都。现场测量表明，大多数城市符合当地标准但不符合世界卫生组织的指导方针，这表明当地的年度限值应更加严格。确定了PM日变化中的两个峰值（与车辆排放有关）以及中午左右更陡峭的下降（与风速和边界层高度增加有关）。趋势分析表明，波哥大和麦德林的PM年度趋势呈下降趋势（在-0.8μg/m³和-1.7μg/m³之间），这对应于有效的政策。相比之下，卡利的年度趋势呈上升趋势（0.8μg/m³），最有可能是由于来自高度污染的邻近城市的北向气流产生的短程传输，这也影响了卡利的PM日循环，或者是由于当地动态。超标情况表明，这些政策在年度尺度上有效，但在每日尺度上无效。这些结果为进一步研究提供了首个输入，目的是在调整现行政策或实施新政策和措施之前，更好地了解污染物，这些政策和措施需要包括国际、区域和城市间关于污染传输的联合努力。
