SDG 11 | sustainable cities and communities
The majority of cities on the planet exceed the limits of polluting particles established by the WHO
At the end of 2021, the World Health Organization (WHO) revised its air quality standards, tightening limits that left a clear conclusion: “No city in the world met good air quality.” This is reflected in the IQAir survey that monitors pollution in large cities.
With these data, the WHO recommends that the average annual readings of small and dangerous airborne particles known as PM2.5 do not exceed 5 micrograms per cubic meter. “All the studies focus on microparticles, but there is also scientific evidence that the thickest ones also have an impact on health,” says Cristina Martínez, pulmonologist and coordinator of the environmental area of the Spanish Society of Pulmonology and Thoracic Surgery (SEPAR). ).
Health risks are associated with suspended particles with a diameter equal to or less than 10 and 2.5 microns (µm) (PM₁₀ and PM₂.₅, respectively). “The mildest symptoms for the entire population are itchy eyes, irritative cough or sore throat,” says Martínez.
“It is unacceptable to still have 7 million preventable deaths and countless years of good health lost, also preventable, due to air pollution,” warned María Neira, director of the WHO Department of Environment, Climate Change and Health. “Contamination to a greater degree affects the older population and the younger ones,” says Martínez.
“It is unacceptable to still have 7 million preventable deaths and countless years of good health lost, also preventable, due to air pollution”
Maria Neira
Director of the Department of Environment, Climate Change and Health of the WHO
In Spain, according to IS Global, polluted air in cities causes up to 17,679 deaths that would be preventable with better air quality. “It’s interesting to see how pollution affects our daily lives,” says Dyson engineer Scott Lowther. “By meeting him, people change their daily habits,” he adds.
This happened in London after an investigation carried out with Kings College London and the Greater London Authority. The study included the participation of 258 children from five schools in London, with the aim of knowing the exposure of students to two pollutants.
“We capture the particles in the air and mix them with GPS data to know the exact position,” Lowther points out. A small-scale replica of the fixed measurement stations in cities that is carried on the back in the form of a backpack. “In addition, we collect environmental measures such as temperature and humidity, which are useful for measuring comfort,” she adds.
Engineers designed the backpack wearable air monitoring device based on existing air sensing technology used in Dyson air purifiers. To do this, a completely new circuit board was made to fit in the backpack, with three main sensors that use unique algorithms to process data.
Close-up device. /
On one board is a sensor that measures temperature and humidity, and another that is a gas sensor that can detect NO2 and VOCs. The third sensor, the dust sensor, is larger than the other two, is in a separate module, and uses lasers to detect PM2.5 and PM10.
Mapping Madrid
Talking about pollution means putting the focus on big cities. “Madrid breached the WHO legal limit in 2021. It was the only one of the 800 Spanish cities to breach it,” says Ecologists in Action in its report on air quality in Spain in 2021 published last summer.
Measurement in Gran Vía. /
“The data collected in Madrid is quite good, but there are worrying peaks,” warns the Dyson engineer. The information was collected on June 13 and 14, two days marked by an orange alert for high temperatures, according to the State Meteorological Agency. “It’s important, because everything has an influence,” says Lowther. “Contamination is much more common in winter, because the air is calmer and our device captures it more,” explains the engineer. “If it’s very hot the air is more turbulent with more currents and more mixing,” he notes.
The highest levels are “concentrated near the roads.” The morning jam at the entrance to Madrid and the walk along Gran Vía are the highest figures of PM 2.5 and PM 10 recorded by the Dyson device. “Car exhaust pipes often emit particulates, and there can be quite high levels near them,” says Lowther. “Another thing that is not taken into account is that particles are also generated by the wear of the tires and brakes of the cars,” he warns.
Graphic particles. /
PM are mainly generated by the combustion of fuels in different sectors, such as transport, energy, households, industry and agriculture. Both PM₂,₅ and PM₁₀ are able to penetrate deep into the lungs, but PM₂,₅ can even enter the bloodstream, mainly affecting the cardiovascular and respiratory systems, as well as other organs.
“Each time we inhale we put in 500 ml of air with each puff and we do it an average of 14 times per minute,” explains Martínez. “If they carry contaminants, they reach the depths of the lung,” says the coordinator of the SEPAR area.
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