Lockdown measures led to air pollution decrease in several countries around the world such as China and India, whereas other regions experimented an increase in pollutant concentrations. Northern ...South America (NSA) was one of those areas where pollution changed during lockdown due to high fire activity. This study aims to analyze, for the first time in NSA, the behavior of selected criteria air pollutants during the implementation of the SARS-CoV-2 lockdown in two high populated cities of the region: Bogotá and Medellín in Colombia. A set of tools including surface measurements, as well as satellite and modeled data were used. 24-hour average concentrations of PM10, PM2.5, and NO2 were collected from air quality stations for the lockdown period ranging from February 21 to June 30, 2020. The Copernicus Atmosphere Monitoring Service (CAMS) was used to analyze the fire flux OC as a biomass burning (BB) indicator, and tropospheric NO2 concentrations were retrieved from TROPOMI. The HYSPLIT model was used to analyze back trajectories and fire data were obtained from MODIS sensor measurements. Our analysis shows short-term background NO2, PM10, and PM2.5 concentration reductions of 60%, 44%, and 40%, respectively, for the strict lockdown; and 62%, 58%, and 69% for the relaxed lockdown. Corresponding long-term reductions were of 50%, 32%, and 9% for the strict lockdown; and 37%, 29%, and 19% for the relaxed lockdown. Regional BB increased PM2.5 concentrations by 20 μg/m3 during the strict lockdown, and the Saharan dust event increased PM10 concentrations up to 168 μg/m3 in Bogotá, and 104 μg/m3 in Medellín, bringing an additional risk of morbidity and mortality for population. Regional BB has several causes that need to be properly managed to benefit local air quality improvement plans. Future cleaner transport policies equivalent to reduced lockdown mobility could bring pollution close to WHO guidelines.
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•Short-term NO2, PM10, PM2.5 decreased by 60%, 44%, and 40% respectively during the strict lockdown.•Short-term NO2, PM10, PM2.5 decreased by 62%, 58%, and 69% respectively for the relaxed lockdown.•Long-term NO2, PM10, PM2.5 reductions were of 50%, 32%, and 9% respectively for the strict lockdown.•Regional biomass burning increased PM2.5 concentrations by 20 μg/m3 during the strict lockdown.•Policies equivalent to reduced lockdown mobility could bring pollution close to WHO guidelines.
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•We estimate on-road traffic emissions for Bogotá using a traffic assignment model.•Private cars are the main contributors accounting for 60% CO and SO2 emissions.•Old vehicles ...without catalytic converter technology are high emitters.•Transit buses and BRT, combined, account for 7% of PM10 emissions.•Local street traffic accounts for 15%–25% of CO, SO2, VOC, NOx, PM10 emissions.
This paper presents a traffic-related air emissions inventory of a developing megacity using a traffic assignment model that results in a detailed temporal and spatial emission representation, disaggregating emissions sources by vehicle type and hour of the day, for five criteria air pollutants.
Transportation policy and planning decisions, including decisions on new infrastructure and public transport improvements, affect local and global environmental conditions. This work studies the ...effect of increased road capacity on traffic-related emissions in Bogotá using a tool that couples a transportation model with emission factors from COPERT IV. We followed a parametric approach varying transport supply and demand, comparing three scenarios: a baseline scenario that represents the transportation system in Bogota in 2015; scenario 1 incorporates five highway capacity-enhancement projects in Bogotá and assumes insensitive travel demand; scenario 2 incorporates the new highway projects but assumes a demand increase of 13% in vehicle trips with private cars. Results include daily and annual values of traffic-related emissions of five air pollutant criteria: CO, NO
x
, PM
10
, SO
2
, and VOC for the baseline scenario, scenario 1, and scenario 2. We found a reduction in emissions after adding highway capacity and assuming inelastic demand (scenario 1). Scenario 1 results in a 15% reduction in PM
10
emissions and a 10% reduction in NO
x
emissions. In contrast, results for scenario 2 suggest increased emissions for all air pollutant criteria (e.g., VOC and CO emissions increase by 21% and 22% compared with the baseline scenario). Therefore, new traffic demand would eliminate the emission savings observed in scenario 1 and could potentially further degrade air quality in Bogotá. While an exact estimate of induced demand that may result from highway expansion in Bogotá is not available, this analysis highlights that such projects could lead to an increase in emissions unless there is a combined effort to managing demand of private vehicle trips.
•Colombia's on-road transportation emissions from 1990 to 2020 have been calculated.•Total transport emissions and trends have been compared with international sources.•High-resolution spatial ...distribution of transportation emissions has been computed.
Road traffic-related air pollution costs society in terms of lost lives, health problems, and financial damages. For directing regulatory actions and enhancing air quality, governments require emission inventories and trends over time across all geographic areas. This study provides a high-resolution spatially disaggregated on-road transportation emissions inventory in Colombia from 1990 to 2020. Our estimates followed a top-down approach that accounted for local characteristics such as fleet technology, fuel consumption, road infrastructure, and activity factors at a national and state level. We report annual CO2, CH4, NOx, VOCs, PM2,5, and black carbon at a spatial resolution of 0.01° x 0.01°. Economic crises (1998–2001), stringent emission requirements (2011), and the most recent sanitary quarantine (2020) all have an impact on emissions patterns, which grow at a slower rate than vehicle activity. For the annual emissions of CH4, CO, and PM2.5, the growth of motorbikes in the vehicle fleet is particularly crucial.
To tackle the current pressing atmospheric science issues, as well as those in the future, a robust scientific community is necessary in all regions across the globe. Unfortunately, this does not yet ...exist. There are many geographical areas that are still underrepresented in the atmospheric science community, many of which are in the Global South. There are also larger gaps in the understanding of atmospheric composition, processes, and impacts in these regions. In this opinion, we focus on two geographical areas in the Global South to discuss some common challenges and constraints, with a focus on our strengths in atmospheric science research. It is these strengths, we believe, that highlight the critical role of Global South researchers in the future of atmospheric science research.
A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal ...of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD). The two cities, New York (USA) and London (UK) stood out with ∼3.5 to 30 times higher total FR concentrations as compared to other major cities, with total concentrations of OPEs of 15,100 and 14,100 pg/m3, respectively. Atmospheric concentrations of OPEs significantly dominated the FR profile at all sites, with total concentrations in air that were 2–5 orders of magnitude higher compared to other targeted chemical classes. A moderately strong and significant correlation (r = 0.625, p < 0.001) was observed for Gross Domestic Product index of the cities with total OPEs levels. Although large differences in FR levels were observed between some cities, when averaged across the five United Nations regions, the FR classes were more evenly distributed and varied by less than a factor of five. Results for Toronto, which is a ‘reference city’ for this study, agreed well with a more in-depth investigation of the level of FRs over different seasons and across eight sites representing different urban source sectors (e.g. traffic, industrial, residential and background). Future sampling periods under this project will investigate trace metals and other contaminant classes, linkages to toxicology, non-targeted analysis, and eventually temporal trends. The study provides a unique urban platform for evaluating global exposome.
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•A global initiative targeting 20 megacities/major cities to monitor POPs in urban air.•Levels of OPEs, PBDEs, NFRs, HBCDD and TBBPA reported here from initial sampling.•GDP of cities had significant positive correlation with the levels of OPEs.•OPEs were 2–5 orders of magnitude higher than other FRs across the globe.•Relatively even distribution of FRs, when averaged across the five United Nations’ regions.
A global study across 20 megacities/major cities reporting urban air concentrations of flame retardants and plasticizers.
Agro-industrial areas are frequently affected by various sources of atmospheric pollutants that have a negative impact on public health and ecosystems. However, air quality in these areas is ...infrequently monitored because of their smaller population compared to large cities, especially in developing countries. The Cauca River valley (CRV) is an agro-industrial region in southwestern Colombia, where a large fraction of the area is devoted to sugarcane and livestock production. The CRV is also affected by road traffic and industrial emissions. This study aims to elucidate the chemical composition of particulate matter fine mode (PM2.5) and to identify the main pollutant sources before source attribution. A sampling campaign was carried out at a representative site in the CRV region, where daily averaged mass concentrations of PM2.5 and the concentrations of water-soluble ions, trace metals, organic and elemental carbon, and various fractions of organic compounds (carbohydrates, n alkanes, and polycyclic aromatic hydrocarbons – PAHs) were measured. The mean PM2.5 was 14.4±4.4 µg m−3, and the most abundant constituent was organic material (52.7 % ± 18.4 %), followed by sulfate (12.7 % ± 2.8 %), and elemental carbon (7.1 % ± 2.5 %), which indicates the presence of secondary aerosol formation and incomplete combustion. Levoglucosan was present in all samples, with a mean concentration of (113.8±147.2 ng m−3), revealing biomass burning as a persistent source. Mass closure using the elemental carbon (EC) tracer method explained 88.4 % on PM2.5, whereas the organic tracer method explained 70.9 % of PM2.5. We attribute this difference to the lack of information of specific organic tracers for some sources, both primary and secondary. Organic material and inorganic ions were the dominant groups of species (79 % of PM2.5). OMprim and OMsec contribute 24.2 % and 28.5 % to PM2.5. Inorganic ions as sulfate, nitrate, and ammonia constitute 19.0 %, EC 7.1 %, dust 3.5%, particle-bounded water (PBW) 5.3 %, and trace element oxides (TEOs), 0.9 % of PM2.5. The aerosol was acidic, with a pH of 2.5±0.4, mainly because of the abundance of organic and sulfur compounds. Diagnostic ratios and tracer concentrations indicate that most PM2.5 was emitted locally and had contributions of both pyrogenic and petrogenic sources, that biomass burning was ubiquitous during the sampling period and was the main source of PAHs, and that the relatively low PM2.5 concentrations and mutagenic potentials are consistent with low-intensity, year-long biomass burning (BB) and sugarcane pre-harvest burning in the CRV.
Objetivos Describir e interpretar las metodologías y resultados de los principales estudios relacionados con el monitoreo de contaminación atmosférica en ciclistas.Métodos Se buscaron y analizaron ...las investigaciones a nivel nacional e internacional de los últimos diez años en las bases de datos Cochrane, Scopus, Embase, Science Direct y Pubmed. La búsqueda se realizó de Agosto a Septiembre del año 2017 usando los siguientes descriptores de búsqueda para MeSH: air pollution, bicycling, environmental exposure, enviromental health, inhalation exposure, environmental pollutants, transportation, public health y toxicology, y para DeCS: contaminación del aire, ciclismo, exposición a riesgos ambientales, contaminantes ambientales, inhalación, transportes, salud pública y toxicología.Resultados Se identificaron diecinueve artículos publicados elegibles. La mayoría de los estudios se realizaron en Europa y Estados Unidos. En Latinoamérica se han reportado cuatro estudios. Otros estudios buscaban comparar la exposición en distintas rutas en bicicleta, comparar trayectos de una misma ruta, y otros determinar la relación distancia vs exposición. De igual manera, variables como el tráfico vehicular, la distancia a las fuentes de emisión y el tipo de ciclorruta, juegan un papel fundamental en la exposición a contaminantes en ciclistas.Conclusiones Se encontraron diversas variables que influyen de forma directa o indirectamente en la exposición a la contaminación del aire de los usuarios de bicicleta, así como algunos factores que pueden reducir la exposición a estos contaminantes.
Se analizó la variación temporal y espacial del tráfico automotor en la zona urbana del Distrito de Santiago de Cali y su relación con la concentración de material particulado, durante el primer ...semestre del año 2020. Se utilizaron datos de tráfico automotor compartidos por la Secretaría de Movilidad de Cali y datos de concentración de PM2.5 y PM10 medidos por el Sistema de Vigilancia de Calidad del aire de la entidad ambiental DAGMA. Se evaluó el registro de los flujos vehiculares en la ciudad, especialmente de motos y automóviles. Se analizó el comportamiento horario de todas las variables. Dado que el periodo de estudio incluye el primer periodo de aislamiento debido a la pandemia por COVID-19, se realizó el análisis de variables de tráfico y contaminantes para tres sub-periodos denominados: pre-aislamiento, aislamiento y post-aislamiento. Se observaron disminuciones de PM hasta del 69% durante el periodo de aislamiento en comparación con el periodo previo. Se encontró que hay dos puntos en la ciudad que muestran mayor tráfico y que registran las mayores concentraciones de material particulado, el primero ubicado en el centro y otro en el sur de la ciudad. Se encontró que la alta afluencia en estos puntos, responde a características de alta oferta y aglomeración de ciertos servicios, lo que aumenta el número de viajes hacia esas zonas. Finalmente, se analizó la variabilidad espacial de la concentración de PM10 y PM2.5, confirmándose la relación entre las altas concentraciones de estos contaminantes con las vías de alto tráfico vehicular en la ciudad. Los resultados permiten confirmar que las fuentes móviles son una de las principales causas del detrimento de la calidad del aire en la ciudad.
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