Delhi-NCR air pollution and stroke risk: How toxic air harms blood vessels and ways to protect yourself

New Delhi: The rising air pollution in the Delhi-NCR region is one of the potentially modifiable risk factors for brain stroke. There is an increased risk of ischaemic stroke after short-term (days) and long-term (years) exposure to air pollution. Delhi’s air pollution is the most pernicious consequence of indiscriminate industrialisation and urbanisation.

Air pollution is a heterogeneous, complex mixture of gases, liquids, and particulate matter. The larger particles (PM10) are more common in industrial emissions, whereas the smaller particles (PM2.5 and PM0.1) result mainly from traffic emissions.

Air pollution and types of stroke

The effect of air pollution seems most pronounced in patients with ischaemic stroke due to large artery disease or small vessel disease and in patients with pre-existing cardiovascular risk factors, without clear sex or age differences.

Short-term exposure to air pollution increases the risk of intracerebral haemorrhage but not the risk of haemorrhagic stroke overall. Long-term exposure seems to increase the risk of haemorrhagic stroke, but few studies have focused specifically on intracerebral haemorrhage.

How polluted air damages blood vessels

The underlying mechanism may be related to increases in heart rate and blood pressure, fibrinogen, and blood coagulation factors, arterial vasoconstriction, inflammatory mediators (eg, C-reactive protein [CRP]), and endothelial injury/dysfunction. Inhaling toxic air creates oxidative stress and damages the inner lining of blood vessels (endothelial dysfunction).

How to reduce exposure

Preventive measures include using a well-fitted N95 or N99 mask outdoors, running HEPA air purifiers inside your home and keeping windows closed during peak pollution hours. Strenuous exercise outdoors should also be avoided when the air pollution is high.

(By Dr Vivek Kumar, Principal Director & Head, Neurology, Max Hospital, Delhi)

Disclaimer: This article is written by the doctor mentioned above and is intended for informational purposes only. The findings should not be considered medical advice or used for self-diagnosis or treatment. Consult a qualified healthcare professional for personalised guidance.