Air pollution in cities harms children's brains, raises risk of Alzheimers: Research

When air particulate matter and components such as metals and toxins are inhaled and swallowed, they pass through damaged cell barriers and cause long-lasting damage, found researchers.

Children living in polluted cities have higher chances of developing brain inflammation and neurodegenerative changes that raise the risk of diseases such as Alzheimer's or Parkinson's, according to researchers.

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When air particulate matter and components such as metals and toxins (like carbon and sulphur) are inhaled and swallowed, they pass through damaged cell barriers — including in the brain, lungs and gastro-intestinal tract — and cause long-lasting damage, found researchers at the University of Montana.

The team from the US university compared 58 serum and cerebrospinal fluid samples from a control group living in a low-pollution city and matched them by age, gender, socioeconomic status and education to 81 children living in Mexico City.

Children living in Mexico City were found to have higher serum and cerebrospinal fluid levels of auto-antibodies against key neural proteins and combustion metals, which damages the brain over time.

The result of constant exposure to air pollution and damage to all barriers eventually has significant consequences later in life. The paper appeared in the Journal of Alzheimer's Disease.

Air pollution a big killer in India

Polluted outdoor air caused 620,000 premature deaths in India in 2010, the last year for which nationwide data is available. This was a six-fold jump from the 100,000 deaths in 2000, said the Global Burden of Disease 2013, which tracks deaths and illnesses from all causes every 10 years.

Of the 180 cities monitored by India’s Central Pollution Control Board in 2012, only two — Malappuram and Pathanamthitta in Kerala — meet the criteria of low air pollution (50% below the standard).

Air pollution killed 7 million people in 2012, causing one in eight of the total deaths globally, said the World Health Organization (WHO).

The new estimate, which includes both outdoor and indoor air pollution, is almost double the earlier WHO estimate of 3.7 million deaths for outdoor air pollution in 2012.

Indoor air pollution caused 4.3 million deaths in 2012 in homes cooking over coal, wood and biomass stoves, say the current estimates. Worldwide, 2.9 billion people live in homes using wood, coal or dung as their primary cooking fuel.

This makes air pollution the world’s biggest environmental health risk, with most deaths being caused by heart disease, strokes or chronic obstructive pulmonary disease.

It is also linked to deaths from lung cancer and acute respiratory infections.

In India, air pollution is the biggest cause of death after high blood pressure, indoor air pollution (mainly from smoking chullahs), tobacco use and poor nutrition.

Deaths due to outdoor air pollution

• 40% - heart disease

• 40% - stroke

• 11% - chronic obstructive pulmonary disease (COPD)

• 6% - lung cancer

• 3% - acute lower respiratory infections in children.

Deaths caused by indoor air pollution

• 34% - stroke;

• 26% - heart disease;

• 22% - COPD;

• 12% - acute lower respiratory infections in children;

• 6% - lung cancer.

Source: World Health Organisation