Gas flaring and illegal refining in Nigeria’s Niger Delta region contribute significantly to environmental pollution, public health crises, and economic losses. These activities release particulate matter (PM₂.₅, PM₁₀), volatile organic compounds (VOCs), nitrogen oxides (NO), sulfur dioxide (SO₂), carbon monoxide (CO), heavy metals, and dioxins, which have been linked to cardiovascular diseases, respiratory disorders, neurological impairments, and adverse reproductive outcomes. Studies conducted in Rivers, Bayelsa, and Delta States reveal that pollutant levels exceed WHO-recommended safety limits by over 400%, correlating with increased risks of hypertension, myocardial infarction, chronic obstructive pulmonary disease (COPD), neurotoxicity, and adverse pregnancy outcomes (Ehumadu, Uyigue, & Ndekwu, 2021). The economic burden of gas flaring is estimated at $7.4 billion annually due to healthcare costs, lost productivity, and environmental damage (World Bank, 2022). This paper integrates air quality data, pathophysiological mechanisms, and epidemiological evidence to assess health risks.