Which pollutant is considered most hazardous to individuals with pre-existing heart conditions?

Carbon monoxide is considered the most hazardous pollutant for individuals with pre-existing heart conditions due to its ability to interfere with the blood's capacity to carry oxygen. When inhaled, carbon monoxide binds to hemoglobin in red blood cells much more effectively than oxygen does, forming carboxyhemoglobin. This significantly reduces the amount of oxygen available to the body’s tissues and organs, including the heart. For individuals with heart conditions, the heart already struggles to supply adequate oxygen to meet its demands, and further reduction in oxygen availability can exacerbate symptoms, lead to increased heart rate, and can even result in serious complications, including heart attacks.

In contrast, while sulfur dioxide, nitrogen oxide, and carbon dioxide have their own health effects, they do not specifically pose the same level of acute oxygen deprivation risk as carbon monoxide does. For instance, sulfur dioxide can aggravate asthma and respiratory issues, but its direct impact on heart function is less severe compared to the effects of carbon monoxide. Nitrogen oxides can also affect lung health and exacerbate respiratory conditions but are not primarily known for their cardiovascular impact. Carbon dioxide is a natural byproduct of metabolism and is not typically classified as a hazardous pollutant in the same way that carbon monoxide is concerning heart health,