Gaseous pollutants linked to pulmonary diseases: East meets West

Abstract

Air pollution represents a critical global health challenge, especially in densely populated urban areas of developing countries such as Pakistan, where it ranks among the top five most affected Asian nations. Despite its significance, data on the health impacts of gaseous pollutants (O₃, NO, NO₂, HNO₃, and SO₂) are scant due to economic constraints and inadequate measurement infrastructure. This pioneering study is the first to quantitatively assess the morbidity risks associated with exposure to these pollutants in Karachi, a megacity in Pakistan, utilizing a robust cross-sectional design. We collected 400 air quality samples over four distinct seasons, correlating these with health data from over 12,000 hospital admissions for respiratory issues. Our results reveal significant associations between ozone exposure and a range of pulmonary diseases—including asthma, tuberculosis, and shortness of breath—across both genders. Specifically, sulfur dioxide (SO₂) exposure was linked to increased shortness of breath in males, while exposure to nitric acid was more likely to cause COPD in males than in females. Additionally, nitrogen oxides (HNO₃) were primarily associated with asthma in males. These associations were particularly pronounced in the 0–50 age group, suggesting a demographic at greater risk. These findings not only corroborate the global body of research on the health implications of urban air pollution but also provide critical new insights into the severe impacts within Karachi. The evidence presented underscores the urgent need for enhanced air pollution control policies and public health strategies tailored to the needs of rapidly urbanizing areas in Pakistan.