Each source of combustion releases PM 2.5 and the kitchen is one of the most dangerous environments. A connection has been found between toxic air pollutants and dementia
Breathe in fine polluting dust, especially the PM 2.5 particles may increase the risk of developing dementia. is the conclusion of an extensive meta-analysis conducted by scientists at the University of Havard and published in the The British Medical Journal. It has long been known that inhaling these microscopic particles, less than 2.5 microns wide (about 3% the width of a human hair) can cause a number of serious health problems. The relationship between PM 2.5 and dementia is quite recent, but if we can reduce exposure to pollution we could reduce the burden of this condition around the world, commented the study’s lead author. Marc Weisskopfprofessor of environmental epidemiology and physiology at the Harvard Th Chan School of Public Health.
The spread of dementia
Today over 57 million people worldwide live with some form of dementia and estimates suggest that the number will increase to 153 million by 2050. The investigations conducted so far assume that around 40% of these cases are connected to potentially modifiable risk factorsincluding exposure to air pollutants.
The connection between dementia and PM 2.5
The new meta-analysis of the British Medical Journal looked at 16 observational studies and found consistent evidence of a connection between PM 2.5 and dementiaeven when an individual’s annual exposure was less than 12 micrograms per cubic meter of air, which the current US Environmental Protection Agency (EPA) standard. According to the air quality guidelines of theWorld Health Organization more restrictive, annual exposure of 5 micrograms or more of PM 2.5 per cubic meter increases the risk of mortality in a linear manner: with 10 micrograms there is an increase in mortality of 4%; with an annual exposure of 25 micrograms a 16% increase in mortality is accepted. To better understand what orders of magnitude we are talking about, a grain of rice weighs about 30 micrograms, almost three times the weight of PM 2.5 particles tolerated by the EPA in a year. Scientists have found a 17% increase in dementia risk for every two microgram per cubic meter of air increase in annual exposure to PM2.5 as well as minor increases in risk due to breathing nitric oxide and nitrogen dioxide, pollutants that mostly derive from exhaust gases.
The direct effect on the brain: a mechanism not yet fully understood
Dementia is just one of the problems caused by air pollution. Many studies have linked pollution to lung tumors, heart diseasestroke, low birth weight, circulation problems, worsening asthma, diabetes, cognitive decline, congenital malformationspremature deaths
It’s unclear how air pollution affects the development of dementia but scientists speculate that the PM 2.5 may have a direct effect on the braintraveling directly from the lungs to the brain, irritating the cerebral blood vessels. Over time, this mechanism could lead to vascular dementia, the most common form of dementia after Alzheimer’s. However, only a small fraction of the tiny PM 2.5 particles can cross the blood brain barrier and it is unclear whether enough particles can actually enter the brain and cause enough damage to lead to dementia (this barrier can be crossed by PM 2.5 particles instead). ultrafine, even smaller). it is therefore likely, according to the scientists, that air pollution may contribute to a decline in mental capacity and dementia, particularly in older people.
The researchers also found that once in the brain the particles are cleared only very slowly. Animal studies so far have shown that diesel engine exhaust creates an inflammatory response in the brain and damages cells, but it is unclear how this translates to humans. There is as yet no direct quantification of the effects of air pollutants on cognitive decline and dementia. Some scientists speculate that the pollution could be related to thechronic inflammation in the body or the buildup of beta-amyloid levels in the blood. It is known that patients with Alzheimer’s disease often have abnormal levels of amyloid beta which clump together to form plaques that prevent neurons from functioning properly.
Where are the pollutants concentrated?
But what is the real exposure to PM 2.5? According to a recent study published in The Lancet 99% of the world‘s population exposed to levels of PM 2.5 considered unhealthy, with concentrations above 5 micrograms per cubic metre. These contaminants come from construction sites, roads, gas car exhaust and trucks, factories, fires. But actually each combustion source releases PM 2.5 particles – points out George Buonannofull professor of Environmental Technical Physics at the University of Cassino and at the Queensland University of Technology in Brisbane (Australia) – including fireplaces, pallet stoves,
cucine a gas
but also, albeit to a lesser extent, induction hobs. Because of this the prevailing indoor exposure to pollutants since you spend a lot of time indoors.
The limitations of studies measuring the consequences of pollution
Typically, studies to calculate exposure to PM 2.5 levels take i values of a public exchange outdoors in relation to the population residing in the area, and from here the incidence of a specific pathology is observed (which can be lung cancer, dementia, cardiovascular diseases). The control unit representative of air quality in an urban outdoor context, but the problem is that all the indoor part neglectedthe question that many scientists are wondering if the air quality of cities is actually representative of the individual’s exposure to pollutants.
How important is indoor pollution
Emblematic is a work published in 2015 in which people equipped with PM 2.5 detectors were monitored for 24 hours: a large oscillation was observed between the value of the common reference control unit and the personal value, which result double compared to that of the control unit, confirming that the prevailing indoor exposure to pollutants underlines Buonanno. Similarly, another study, this time carried out on ultrafine particles, even smaller, investigated exposure to pollutants from 24 married couples. Women, all housewives, experienced 30-40% more exposure than husbands who went to work: even people who live under the same roof can have different exposures based on the places they frequent and the house, especially the kitchen, does not seem to be the safest place.
Controlled mechanical ventilation
Most people do not have the ability to control and manage the quality of the air they breathe in the external environment – underlines Giorgio Buonanno – however each of us can do a lot to defend ourselves from exposure to indoor pollutants, with mechanical ventilation systems controlled. We have all the technologies available to purify the air in our homes and offices, with economic costs that are decidedly lower than the investments necessary to reduce fine dust in outdoor environments. All of this could make a huge difference to the global health burden, including cancer, heart disease, dementia, but also infectious pathogens such as SARS-CoV-2.
April 12, 2023 (change April 12, 2023 | 07:12)
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