Delhi-NCR air pollution: What is AQI and how does a high AQI of 500 affect your health in the long run?

As citizens of Delhi woke up today, they did not expect to be breathing in air that would be equivalent to smoking 49.02 cigarettes every day. Reaching an unprecedented new high, the air quality as recorded by the Central Pollution Control Board (CPCB) as of 4 pm today was: Anand Vihar: 500, Vivek Vihar: 498, Chandni Chowk: 480. As the public is unknowingly exposed to severe health risks, this prompts the question: what happens to the human body when exposed to such dangerous levels of air pollution?

What is AQI and how to read it?

The Air Quality Index (AQI) is a system used to measure the concentration of five major air pollutants: ground-level ozone, particulate matter (PM), carbon monoxide, nitrogen dioxide, and sulfur dioxide. Established by the Environmental Protection Agency (EPA), the AQI provides a daily snapshot of air quality to help people understand the potential health risks of the air they breathe. Now, the AQI ranges from 0 to 500, with higher numbers indicating worse air quality. An AQI of 0 to 100 signals air that is considered safe for most people, with minimal risk of health effects. When the AQI exceeds 100, air quality can begin to affect sensitive groups, and above 200, it poses serious health risks for the general population. The average AQI levels of Delhi as of today are 450 to 500.

Overall physical effects of bad air quality

According to Dr. Arup Halder, a senior pulmonologist at CMRI Hospital who spoke to the Business Standard, when the AQI worsens, pollutants enter the body through the lungs, affecting various organs in the process. Initial symptoms can range from mild irritations, such as headaches, nasal congestion, and skin problems to more serious conditions. Additionally, long-term exposure to polluted air can cause chronic respiratory diseases like asthma, chronic obstructive pulmonary disease (COPD) and even lung cancer.

Dr. Halder also explains that ultra-fine particulate matter (less than 0.1 micron in size) can travel from the lungs into the bloodstream, triggering systemic effects. These tiny particles not only damage the lungs but can also harm the heart, brain, kidneys and other organs. For instance, air pollution can contribute to hypertension, ischemic heart disease and heart attacks, especially during colder months. Additionally, studies have shown that these particles can affect the brain, leading to cognitive decline, dementia, and strokes, particularly in older adults. In children, long-term exposure can hinder neurological development.

Impact on specific organs

Air pollution has wide-reaching effects on various bodily systems. For the respiratory system, pollutants can aggravate or cause diseases such as asthma, allergic rhinitis, and even more serious conditions like COPD and lung cancer. It can also increase the risk of acute illnesses such as pneumonia and other lung infections.

In the cardiovascular system, air pollution contributes to an elevated risk of heart disease. Fine particulate matter has been linked to heart attacks, strokes, and heart failure, as well as hypertension. Cognitive health is also significantly impacted, with pollution being associated with early cognitive decline, dementia, and Alzheimer’s disease.

The skin isn’t immune either. Exposure to air pollution can lead to conditions like dermatitis, eczema, and accelerated skin ageing. Even internal organs like the kidneys and liver can suffer, with pollution being a potential risk factor for chronic kidney disease and liver damage.

Impact on vulnerable groups: Pregnant women and children

It's also important to consider how certain groups are more vulnerable to the harmful effects of air pollution; even short-term exposure to high AQI levels can have long-lasting effects. For example, pregnant women are at higher risk, as exposure to polluted air can disrupt placental development, harm fetal growth and even lead to long-term epigenetic changes in the child. These changes can predispose children to a variety of diseases in adulthood, reinforcing the idea that many adult health conditions have their roots in early life environmental exposures.

How to stay safe?

The most immediate response would be a fundamental change in government policy but for individual purposes, there are a series of measures that can be taken to make sure you and your family are relatively safe. For one, stay indoors if you can. Get a portable air cleaner/air purifier if possible. Avoid smoking and frying foods since both increase smoke. The effects of poor air quality on the human body are far-reaching and complex. As the AQI worsens, it is crucial to recognise the immediate and long-term health impacts of air pollution, urging the need for stronger measures to reduce pollution and safeguard public health.

Disclaimer: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.