Long-term exposure to air pollution and even small increases could affect mental health, UK study finds.
Asthma and cardiovascular disease are the most well-known damage caused by air pollution. However, autism spectrum and psychotics disorders, schizophrenia, depression, anxiety and cognitive impairment have been linked to air pollution.
Other studies suggested that air pollutants can increase the risk of Alzheimer’s and cause suicides. Some research on pregnant women and children has found that living in a very polluted environment can lead to reduced child intelligence or cause death in utero.
Generally speaking, air pollution could affect all organs of the human body as it was concluded by the Forum of International Respiratory Societies: “Ultrafine particles are easily picked up by cells [of the lungs] and transported via circulation to expose virtually every cell in the body. “
The majority of previous studies regarding the link between mental health and air pollution have focused on depression and anxiety and have shown positive associations with increased concentrations of NO2 and PM2.5
The recent research, published in the scientific journal Social Psychiatry and Psychiatric Epidemiology, is a psychiatric and physical morbidity survey of 1,698 people aged 16 and over residing in 1,075 randomly selected households in the Boroughs of Southwark and Lambeth of London, during the period 2008-2010.
The assessment of exposure to air pollution was carried out mainly on nitrogen oxides (NOx) and fine particles (PM2.5 and PM10). These pollutants are generally emitted by road transport, industries, gas boilers, heating, fuel oil and coal combustion sources, but also by agricultural and natural sources.
The study found that increased PM2.5 , NOx and NO2 were associated with a 18-39% increased odds of common mental disorders, a 19-30% increased odds of poor physical symptoms, and 33% of psychotic experiences for PM10.
However, for mental health research, its broad definition still makes it difficult to assess potential direct causal links with the exposure to air pollution. The causal links are instead proven with neuroinflammation and neurotoxicity that would cause depression and psychosis in the short and long term. But, other uncertainties remain about how the inhaled particles change brain structure then cause those inflammation.