A study conducted on heart patients has shown that tiny particles in the air, black carbon and sulphur dioxide found in heavy vehicle polluted area can cause severe damage to the heart by increasing the ST-segment depression, which disrupts the supply of blood to the heart.

According to researches at the Harvard University, pollution not only play havoc on the lungs but damages the heart as well. This conclusion was drawn after conducting a study on 48 Boston patients suffering with coronary disease. The researches used 24 hour holter monitors to examine the changes in the ST segment depression and noticed that increased levels of a particular pollutant called PM25, along with carbon and sulphur, disrupted the functioning of the heart due to either inflamed heart muscles, or low blood flow.

The effect of vehicular pollution is seen more on patients who have a heart ailment as compared to those with a normal heart. In Dublin, Ireland the percent of deaths due to cardio vascular diseases decreased substantially when coal sales were banned. Therefore, heart patients must be very cautious not to venture into highly polluted areas.