Air pollution is one of the most pressing global environmental challenges today. Major air pollutants such as particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), and volatile organic compounds (VOCs) have severe direct and indirect effects on human health and the environment. These pollutants are often the result of human activities, including industrial processes, transportation, and agriculture. Their widespread presence in the atmosphere has led to significant environmental degradation and public health crises, and understanding their impacts is critical for mitigating their effects. The direct effects of major air pollutants on human health are immediate and can be highly detrimental. Particulate matter, especially PM2.5 (particles with a diameter of less than 2.5 micrometers), is one of the most dangerous pollutants. These fine particles can penetrate deep into the lungs and enter the bloodstream, leading to respiratory issues, cardiovascular diseases, and even cancer. Long-term exposure to high concentrations of PM2.5 has been linked to chronic conditions such as asthma, bronchitis, and emphysema, as well as premature death. Children, the elderly, and individuals with pre-existing respiratory conditions are particularly vulnerable to these effects. Another major air pollutant, carbon monoxide, is a colorless, odorless gas produced primarily from the incomplete combustion of fossil fuels in vehicles, industries, and power plants. When inhaled, carbon monoxide interferes with the body's ability to transport oxygen, leading to symptoms such as dizziness, fatigue, and headaches. In severe cases, it can cause unconsciousness or death. Long-term exposure, even at low levels, can also contribute to cardiovascular and neurological issues. Nitrogen oxides, which are produced primarily from vehicle emissions and industrial activities, have significant direct effects on human health. These gases contribute to the formation of ground-level ozone and particulate matter, which can aggravate respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Nitrogen oxides can also increase the severity of respiratory infections and lead to reduced lung function, particularly in vulnerable populations such as children and the elderly. Sulfur dioxide, mainly released from the burning of fossil fuels like coal, is another harmful pollutant. It can irritate the respiratory system, leading to coughing, wheezing, and shortness of breath. Prolonged exposure to high concentrations of sulfur dioxide can cause severe lung damage and increase the risk of respiratory infections, particularly in individuals with asthma or other chronic lung diseases. Volatile organic compounds (VOCs), which are emitted from a variety of sources including vehicle exhaust, industrial processes, and the use of