The main transmission mechanism of the SARS-CoV-2 virus is airborne, particularly in poorly ventilated indoor environments. Recognizing the importance of this mechanism has taken a long time, despite ...the evidence generated by aerosol scientists from an early stage of the pandemic. Hence, measures applied more widely by the population have focused on the disinfection of surfaces, often in an exaggerated way, while measures focused on reducing the concentration of aerosols in indoor environments, such as adequate ventilation and air filtration, have been timidly promoted. In addition to the progress of the National Vaccination Plan, it is necessary to intensify transmission prevention measures for a safer reopening of the economy. It is therefore urgent, to educate and generate clear guidelines for the evaluation and improvement of ventilation in indoor spaces.
The present study aimed to determine the association between chronic exposure to fine particulate matter (PM2.5), sociodemographic aspects, and health conditions with COVID-19 mortality in Colombia.
...We performed an ecological study using data at the municipality level. We used COVID-19 data obtained from government public reports up to and including July 17th, 2020. We defined PM2.5 long-term exposure as the 2014–2018 average of the estimated concentrations at municipalities obtained from the Copernicus Atmospheric Monitoring Service Reanalysis (CAMSRA) model. We fitted a logit-negative binomial hurdle model for the mortality rate adjusting for sociodemographic and health conditions.
Estimated mortality rate ratios (MRR) for long-term average PM2.5 were not statistically significant in either of the two components of the hurdle model (i.e., the likelihood of reporting at least one death or the count of fatal cases). We found that having 10% or more of the population over 65 years of age (MRR = 3.91 95%CI 2.24–6.81), the poverty index (MRR = 1.03 95%CI 1.01–1.05), and the prevalence of hypertension over 6% (MRR = 1.32 95%CI1.03–1.68) are the main factors associated with death rate at the municipality level. Having higher hospital beds capacity is inversely correlated to mortality.
There was no evidence of an association between long-term exposure to PM2.5 and COVID-19 mortality rate at the municipality level in Colombia. Demographics, health system capacity, and social conditions did have evidence of an ecological effect on COVID-19 mortality. The use of model-based estimations of long-term PM2.5 exposure includes an undetermined level of uncertainty in the results, and therefore they should be interpreted as preliminary evidence.
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•There was not a significant association between long-term exposure to PM2.5 and COVID-19 mortality in Colombia.•Demographic, health system, and social conditions are related to COVID-19 mortality.•Population over 65 years, poverty index, and prevalence of hypertension are associated to the death rate.
En este trabajo se presentan los resultados iniciales del análisis de factores que influyen sobre el comportamiento de la concentración de material particulado en el distrito de Santiago de Cali. Se ...evaluan los impactos del tráfico y el viento sobre el PM2.5 y PM10 en diferentes puntos de la ciudad. Se analizaron bases de datos compartidas por el DAGMA y la Secretaría de Movilidad, ambas dependencias de la Alcaldía de Cali. Se presentan los análisis de tendencias para el parque automotor y concentración de PM2.5 y PM10. Las variables analizadas (PM2.5, PM10 y parque automotor) muestran un aumento sostenido de sus valores a lo largo del tiempo. Se concluye que el aumento del parque automotor incide directamente sobre el detrimento de la calidad del aire de la ciudad en los últimos años. También se evaluó la relación entre el comportamiento horario del PM2.5 y PM10 y la velocidad del viento para diferentes estaciones de monitoreo de la ciudad. Se evidencia que la concentración de material particulado alrededor de las 18 h se reduce por el aumento notable en la velocidad del viento. Se concluye que es importante explorar con mayor profundidad la influencia del tráfico y las variables meteorológicas sobre la contaminación atmosférica de la ciudad.
Bogota registers frequent episodes of poor air quality from high PM10 concentrations. It is one of the main Latin American megacities, located at 2600 m in the tropical Andes, but there is ...insufficient data on PM10 source contribution. A characterization of the chemical composition and the source apportionment of PM10 at an urban background site in Bogota was carried out in this study. Daily samples were collected from June 2015 to May 2016 (a total of 311 samples). Organic carbon (OC), elemental carbon (EC), water soluble compounds (SO42−, Cl−, NO3−, NH4+), major elements (Al, Fe, Mg, Ca, Na, K, P) and trace metals (V, Cd, Pb, Sr, Ba, among others) were analyzed. The results were interpreted in terms of their variability during the rainy season (RS) and the dry season (DS). The data obtained revealed that the carbonaceous fraction (∼51%) and mineral dust (23%) were the main PM10 components, followed by others (15%), Secondary Inorganic Compounds (SIC) (11%) and sea salt (0.4%). The average concentrations of soil, SIC and OC were higher during RS than DS. However, peak values were observed during the DS due to photochemical activity and forest fires. Although trace metals represented <1% of PM10, high concentrations of toxic elements such as Pb and Sb on RS, and Cu on DS, were obtained. By using a PMF model, six factors were identified (∼96% PM10) including fugitive dust, road dust, metal processing, secondary PM, vehicles exhaust and industrial emissions. Traffic (exhaust emissions + road dust) was the major PM10 source, accounting for ∼50% of the PM10. The results provided novel data about PM10 chemical composition, its sources and its seasonal variability during the year, which can help the local government to define control strategies for the main emission sources during the most critical periods.
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•Annual average PM10 levels in Bogota were twice as high as the WHO guidelines.•PM10 levels were maximum during the RS while the highest peaks occurred during the DS.•OM + EC was the major chemical compound of PM10 in Bogota (∼51%).•Vehicle-related emissions were the chief source of PM10 (∼50%).•Significant industrial sources of Pb and Cu were identified.
Research on chemical composition and source apportionment of PM10 in a high–altitude (2600 m above sea level) and tropical megacity during one year of sampling.
It is necessary to evaluate cyclists’ exposure to particulate matter and if they are at a higher risk due to their increased breathing rate and their exposure to freshly emitted pollutants. The aim ...of this pilot study was to determine cyclists’ exposure to PM
10 in a highly-polluted, high-altitude city such as Bogotá, and comment on the appropriateness of building bicycle paths alongside roads with heavy traffic in third world cities. A total of 29 particulate matter (PM
10) measurements, taken at two sampling sites using Harvard impactors, were used for estimating the exposure of users of the 80th street bicycle path to this pollutant. PM
10 dose could be considered as being high, especially due to high concentrations and cyclists’ increased inhalation rates. A random survey was conducted over 73 bicycle path users to determine cyclists’ time, distance and speed on the bicycle path on a daily and weekly basis, their level of effort when cycling and general characteristics, such as this population’s gender and age. Based on this information, the PM
10 average daily dose (ADD
c) for different bicycle path users and the ratio between ADD
c and a reference ADD for people at rest exposed to an indoor concentration of 25 μg m
−3 were estimated. The average increase in ADD was 6%–9% when riding with light effort and by 12%–18% when riding with moderate effort. The most enthusiastic bicycle path users showed ADD
c/ADD
r ratios as high as 1.30 when riding with light effort and 1.64 when riding with moderate effort, thereby significantly increasing their PM
10 exposure-associated health risks.
► Users of bicycle paths alongside main roads in Bogotá are exposed to high PM
10 levels. ► Cycling on such bicycle paths may increase the PM10 average daily dose (ADD) up to 64%. ► The ADD depends strongly on the level of effort and the cycling time.
A set of 16 priority polycyclic aromatic hydrocarbons (PAH) associated with particulate matter (PM), emitted by a diesel engine fueled with petroleum diesel and a 15%-vol. palm oil methyl ester blend ...with diesel (B15), were determined. PM was filtered from a sample of the exhaust gas with the engine running at a steady speed and under no load. PAH were extracted from the filters using the Soxhlet technique, with dichloromethane as solvent. The extracts were then analyzed by gas chromatography using a flame ionization detector (FID). No significant difference was found between PM mass collected when fueled with diesel and B15. Ten of the 16 PAH concentrations were not reduced by adding biodiesel: Benz(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-c,d)pyrene, naphthalene and phenanthrene. The acenaphthene, acenaphthylene and anthracene concentrations were 45%–80% higher when using diesel, whereas those for benzo(k)fluoranthene, benzo(g,h,i)perylene and pyrene were 30%–72% higher when using the B15 blend. Even though the 16 priority-PAH cumulative concentration increased when using the B15 blend, the total toxic equivalent (TEQ) concentration was not different for both fuels.
► Particulate and 16 priority PAH emissions from diesel and biodiesel B15 combustion were measured. ► No difference in particulate matter mass emitted was found. ► The concentrations of 8 priority HAP were lower when using B15. ► No significant difference in the total toxicity equivalent concentration was found.
Rapidly urbanizing cities in Latin America experience high levels of air pollution which are known risk factors for population health. However, the estimates of long-term exposure to air pollution ...are scarce in the region. We developed intraurban land use regression (LUR) models to map long-term exposure to fine particulate matter (PM
2.5
) and nitrogen dioxide (NO
2
) in the five largest cities in Colombia. We conducted air pollution measurement campaigns using gravimetric PM
2.5
and passive NO
2
sensors for 2 weeks during both the dry and rainy seasons in 2021 in the cities of Barranquilla, Bucaramanga, Bogotá, Cali, and Medellín, and combined these data with geospatial and meteorological variables. Annual models were developed using multivariable spatial regression models. The city annual PM
2.5
mean concentrations measured ranged between 12.32 and 15.99 µg/m
3
while NO
2
concentrations ranged between 24.92 and 49.15 µg/m
3
. The PM
2.5
annual models explained 82% of the variance (
R
2
) in Medellín, 77% in Bucaramanga, 73% in Barranquilla, 70% in Cali, and 44% in Bogotá. The NO
2
models explained 65% of the variance in Bucaramanga, 57% in Medellín, 44% in Cali, 40% in Bogotá, and 30% in Barranquilla. Most of the predictor variables included in the models were a combination of specific land use characteristics and roadway variables. Cross-validation suggests that PM
2.5
outperformed NO
2
models. The developed models can be used as exposure estimate in epidemiological studies, as input in hybrid models to improve personal exposure assessment, and for policy evaluation.
The study was part of the South American Emissions, Megacities and Climate Project (SAEMC). The objective was to identify and quantify organic and elemental carbon (OC and EC), monosaccharides, ...polycyclic aromatic hydrocarbons (PAHs), oxy and nitro-PAHs, water-soluble ions (WSI), and elements in particulate matter collected in intensive campaigns during a period (June, 2010) in São Paulo (Brazil), Lima (Peru), and Medellín (Colombia). PM
10
concentration was higher in São Paulo than in the other two sites and 75% of the samples had concentrations above the World Health Organization (WHO) guideline. High concentrations of levoglucosan, a biomass burning tracer, highlighted the importance of this source in the Brazilian megacity. Levoglucosan-to-mannosan ratios for São Paulo suggested sugarcane burning, which in 2010 occurred in 70% of the state municipalities during harvest. Vehicular-related elements (Fe and Cu) had higher concentrations in São Paulo. As and Pb in Medellín were attributed to industrial emissions. Ni in Lima was associated with emissions from metal smelting facilities and ship heavy oil combustion. Higher total PAH concentrations and benzoapyrene equivalent (BaPE) index in São Paulo indicated a stronger influence of vehicular exhaust in this megacity. The results highlighted the importance of biomass burning and vehicular sources for São Paulo, vehicular exhaust, biomass burning, and industrial sources for Medellín, and marine aerosol, together with vehicular, industrial, and ship exhaust, for Lima.
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