Air pollution could pose an existential challenge to human health, caused by a shift in the atmospheric conditions owing to anthropogenic activity. The interactions between air pollution and health outcomes are diverse and complex and include multiple exposure pathways that may lead to the development of cardiovascular disease (CVD). Air pollution is a well-known risk factor for CVD morbidity and mortality, ranking fourth, following high blood pressure, dietary risks and smoking.
Air pollution affects our health in many ways and is now increasingly associated with cardiac ailments. Prolonged exposure to airborne pollutants can cause inflammation and oxidative stress in the circulatory system, heightening the risk of cardiovascular diseases. Poor-quality air can introduce contaminants deep into the bloodstream through the lungs, increasing the likelihood of heart and circulatory issues. These pollutants can narrow and harden blood vessels, impeding blood flow and potentially raising blood pressure. Additionally, they can disrupt the heart’s electrical system, leading to abnormal rhythms, and even cause structural changes like those seen in early-stage heart failure. For individuals with existing heart conditions, the damage can escalate the risk of heart attacks or strokes.
Long-term exposure to air pollution can significantly degrade the quality of life, primarily impacting the respiratory and cardiovascular systems, though other bodily systems may also suffer adverse effects. Irregular oxygen supply raises the risk of cardiac diseases, contributing to escalation in mortality rates as quality of life diminishes over time.
Impact of air pollution in India
Air pollution is one of the primary causes of respiratory illnesses and associated infections, and it is the second major risk factor causing disease burden in India after malnutrition. Pandey et al. (2021) recently reported the economic loss due to morbidity and mortality associated with air pollution using the Global Burden of Diseases (GBD) data. In India around 1.24 million deaths (12.5% of the total deaths) were attributable to air pollution in 2017. Around 60% is from ambient particulate matter (PM) pollution and 40% from HAP.
In 2019 it increased to 1.67 million deaths, which accounts for 17.8% of the total deaths in the country. Ambient air pollution is a major contributor (0.98 million) as compared to household air pollution (0.61 million). The death rate from 1990 to 2019 has increased due to ambient PM and ozone pollution, whereas death rate owing to household air pollution has decreased significantly.
Globally, Air pollution is associated with three of the leading causes of death in the world with significant shares of air pollution-related mortality: stroke (26%), ischaemic heart disease (20.2%), and primary cancer of the trachea, bronchus and lung (19%). Overall, air pollution has been linked to eight million deaths worldwide and more than 100 million disability-adjusted life years annually, with a USD$5trillion global economic impact annually.
Effects of PM 2.5 on heart health
PM2.5 component is one-third the size of red blood cell and enters blood circulation through the lung alveoli either by directly crossing the barrier or translocating through macrophages. The cardiovascular effects of PM2.5 are known to vary according to source and pollutant composition. There are many components contributing to the health effects of PM2.5, but not sufficient evidence to differentiate those constituents (or sources) that are more closely related to specific health outcomes. From a compositional perspective, particulate sulfates, nitrate and organic carbon are most consistently associated with cardiovascular mortality than other PM2.5 constituents, such as iron, potassium, silicon and zinc.
Short term exposure (hours to days) may increase the risk of various arrhythmias, myocardial infarction (MI), stroke and acute exacerbation of heart failure. Short-term increases in systolic blood pressure (BP) (1–5 mmHg) and diastolic BP (1–3 mmHg) occur in response to PM exposure (fine, coarse and diesel exhaust).
In long term, there is a consistent association between PM2.5 levels and BP. Chronic exposure to PM2.5 is associated with significantly larger increases in BP and has also been associated with increased incidence of hypertension.
Precautionary measures
Air pollution poses a significant risk, leading to short-term and long-term health consequences. However, some precautions can be taken to avoid cardiac ailments due to air pollution.
People should stay informed about local air pollution levels by using air quality apps or websites and avoid outdoor activities during high pollution days. Investing in high-quality air purifiers for home and office also helps remove pollutants from indoor air. Opening windows when outdoor air quality is better is also helpful in improving indoor air circulation at home.
Another good way is to place spider plants and peace lilies in the house as they enhance air quality at home. People with existing cardiac ailments should try to stay indoors early in the morning and evening when pollution levels are usually highest.
Drinking plenty of water helps the body eliminate toxins and stay healthy. Eating foods rich in antioxidants, such as fruits and vegetables, can boost the immune system and combat the effects of pollution. Regular exercise also strengthens the immune system, but one should opt for indoor exercise when outdoor air quality is poor.
Much like outdoor pollution, indoor air quality can significantly affect our health, especially considering the amount of time many of us spend indoors. However, there are simple steps we can take to enhance the air quality at home and mitigate the effects of pollution. Opting for solid or liquid cleaning products over aerosols reduces airborne pollutants.
Choosing electricity or gas for cooking and heating, rather than wood or coal, helps minimise pollution. Timely cleaning of the floor prevents buildup of dust and allergens that can release into the air. Installing exhaust fans in kitchens and bathrooms can prevent moisture accumulation, which fosters mold and bacteria growth. Finally, refraining from smoking indoors is crucial for maintaining clean air quality.
Dr Praveen Chandra
(The author is chairman of interventional cardiology division, Medanta - The Medicity)