Cordoba Air Pollution: The air is acceptable, but not always or in all areas
A UNC team has been monitoring the city and province for a decade. While the air quality is acceptable, it is not uniform: certain pollution events occur in certain regions, days and times of the year. The latest measurements and satellite observations from the Gulish Institute. (August 24, 2023)
go through Lucas Gianre
to draft science
University of North Carolina Science and Technology Secretariat
lgianre@unc.edu.ar
How much does air quality affect our health? As we all know, this is very important. But what we don’t know is how much microscopic pollutants are in the air of our cities, especially in the most densely populated cities, which are the ones with the most sources of emissions.
According to a 2018 report by the World Health Organization (WHO), nine out of 10 people in the world breathe air with high levels of pollutants, meaning millions of people die from related causes.
At UNC, a group of scientists has been working for more than a decade to monitor the air in the city of Córdoba and the province of Córdoba at the Laboratory for Atmospheric Contaminants Research (LaICA) in the College of Accurate, Physical Sciences and Natural Sciences.
Laboratory director Hebe Carreras told UNCiencia that air quality in the Córdoba capital was at an acceptable level, taking into account daily averages and exposure over time.
On the other hand, if you focus on certain moments, times and places, the diagnosis changes.
“Air quality is not uniform throughout the city of Córdoba,” the scientist explained. Some areas work well while others don’t, such as where industrial and vehicular emission sources are mixed. However, it is common for pollution incidents in cities to occur on certain days, especially in winter. This is due to the low ambient temperature, combined with the capital’s geographical location in a well, which makes it difficult for pollutants to diffuse and increase their concentration beyond health standards. “
Measurements are made with sensors capable of determining suspended particulate matter (PM), which can be of different sizes (large, fine and ultrafine).
The largest particulate matter, called PM10, is made up of particles like dust, pollen and mold and can trigger allergic reactions, bronchitis and asthma attacks. However, PM2.5 is more risky due to its ability to penetrate the airways more deeply. After inhalation, these particles can enter the bloodstream through the lungs.
boundary
The last measurements taken by the UNC team in the city of Córdoba took place between March and November 2021 in five areas of the city’s public domain (Ferreira, Mattienzo, Aguero, Villa Libertadores and Puerto region).
In no case did fine particulate matter (PM, 2.5) exceed the provincial legal daily limit of 35 micrograms per cubic meter (35 ug/m3) over a 24-hour period.
However, if the new standard (15 micrograms per cubic meter) recommended by the World Health Organization for protecting human health is taken into account, 40% of the days in the two sampling areas exceeded the standard.
In a previous study conducted in 2020, the PM 2.5 concentration in the center of the capital was measured and found that the average daily concentration during the period was 19 micrograms per cubic meter, which also exceeded the limit set by the world entity.
In urban areas, the most common pollutants are particulate matter, carbon dioxide, nitrogen oxides, and volatile organic compounds, among others. Many of these substances are also greenhouse gases that contribute to global warming, coming from two main sources: automobiles and industry.
The results of the UNC study show that manufacturing areas and areas with higher population and vehicle densities exceed the limit.
| Powder Metallurgy Standard2.5 | ||
|---|---|---|
| US EPA 35 μg/m23 |
WHO 15 μg/m²3 |
|
| Aguero | 0 | 30.4 |
| ferreira | 0 | 39.9 |
| Mattienzo | 0 | 38.8 |
| Pueredon | 0 | 22.7 |
| Villa Liberator | 0 | 18.2 |
Tabla. Porcentaje de días en los que se superaron los estándares provinciales o los propuestos por la OMS durante el periodo abril-noviembre 2021 en cada uno de los sitios de muestreo. Fuente: Proyecto aires nuevos para la primera infancia. Laboratorio de Investigación en Contaminantes Atmosféricos (LaICA), FCEFyN. Diciembre de 2021.
“The concentration limits set by the standards are complicated because they can be exceeded over a period of several hours, but when averaged over the whole day, the measurements are relatively low,” Carreras explained. It doesn’t mean that for a few hours someone is moving around the city breathing high levels of air pollutants.”
The time of day is a key aspect. “In Córdoba we observed a very typical pattern of fine particle concentrations. Concentrations rose between 8.30 and 10 in the morning and then started to fall, which is related to the circulation of cars. From 4 or 5 in the afternoon , the concentration starts to rise again, with a peak around 7 or 8 pm. This is related to the reduction of the atmospheric boundary layer, because the temperature drops when the sun shines, causing the pollutants to concentrate,” explained the UNC professor.
“The main source of particulate matter emissions in urban areas is vehicles, especially the oldest vehicles, which have not been maintained and therefore emit extremely high levels,” Carreras said. “Vehicle control and its access to urban centers is a key aspect , because the central area is the most densely populated area, and it is also lower in elevation.”
The more girls the more dangerous
At LaICA, they have already started measuring the atmospheric mass of ultrafine particles. “They are the most dangerous to our health. They are 0.1 microns in diameter and behave almost like a gas,” the researchers said.
He added, “Unlike PM2.5, there is no legislation anywhere in the world to measure or regulate the emission of these particles.”
Ultrafine particles are the focus of current research. “The World Health Organization is reviewing the body of scientific evidence on the harmful effects of such particles. It must be taken into account that their toxicity is measured not only by their quantity, but also by their chemical composition,” Carreras noted.
The toxicity of particulate matter is thought to be determined by this smaller fraction. “They are the most difficult to study because they are so small and they behave very randomly. Thanks to advances in technology, today there are instruments that can measure them, not based on their mass but on their quantity. This is where we are position,” the scientist explained.
from heaven
The Mario Gulich Institute for Advanced Space Studies (IG) relies on UNC and the National Council for Space Activities (Conae), one of its research areas is the monitoring of atmospheric pollutants through satellite sensors.
They looked at atmospheric aerosols (solid or liquid particles), focusing on aerosol optical depth (AOD, Aerosol Optical Depth in English), which allows us to see their abundance in the atmospheric column, mainly from the ground up 12 kilometers above sea level. high. Satellites recognize scattered sunlight by the presence of aerosols.
Measurements in Córdoba in 2022 showed higher levels of pollutants (orange and yellow) in January; conversely, a decline was observed in July, contrary to what the surface sensors showed.
“During summer, we observe higher levels because emitted aerosols are dispersed at higher altitudes; they also increase because the sun facilitates chemical reactions of polluting gases to form these substances. In July, the satellites are to make the right detection Difficulties arise because atmospheric conditions mean that they are closer to the surface, so their concentrations increase, as indicated by surface measurements,” says Fernanda García Ferreyra, IG and researcher at Conae. Abraham Coiman (Gulich Institute) and Verónica Andreo (Gulich-Conicet Institute) also contributed to the report.
Another aspect that affects the dispersion of pollutants is the mountains of Córdoba, where the AOD is lower because they act as a physical barrier so that aerosols generated by the city and its surroundings are not transported there by the wind.
This dynamic is verified in maps recorded in different months in 2022. “During July and September, we observed more aerosols in the east, as winds transported smoke from fires that were then burning in the north of the country to the east, the Gullich Institute experts added:
New Ellis Toddler Project. First report April-September 2021.
Laboratory for Atmospheric Contaminants Research (LaICA). Faculty of Exact, Physical and Natural Sciences. National University of Cordoba. December 2021.
The report was prepared by Abraham Coiman (Institut Gulich), Verónica Andreo (Institut Gulich – CONICET) and Fernanda García Ferreyra (Institut Gulich – CONAE).