Impact of Seasonal Smog on Asthma Exacerbations in Urban Pakistani Adults
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Background: Seasonal smog is a recurrent environmental hazard in urban Pakistan and may aggravate asthma through short-term exposure to particulate matter and irritant gases. Objective: To determine the frequency of asthma exacerbations during the smog season, examine the relationship between AQI and hospital admissions, and evaluate medication adherence and preventive behaviours among urban Pakistani adults with asthma. Methods: This prospective cohort study followed 250 adults with physician-diagnosed asthma from October through January. Participants underwent baseline assessment and weekly follow-up for exacerbations, emergency visits, hospital admissions, medication adherence, preventive behaviours, and AQI exposure. Categorical associations were assessed using the chi-square test, while weekly mean AQI and admission counts were examined using Pearson correlation. Results: At least one exacerbation occurred in 137 participants, corresponding to 54.8% (95% CI: 48.6–60.9), and 202 exacerbation episodes were recorded. December had the highest mean AQI (318), exacerbation count (71), emergency visits (39), and admissions (27). Of 66 admissions, 51 (77.3%) occurred on unhealthy, very unhealthy, or hazardous AQI days. Weekly mean AQI correlated positively with admissions (r=0.72; p=0.003). Exacerbations occurred in 63.4% of participants with poor adherence and 44.8% with good adherence (RR=1.42; 95% CI: 1.11–1.80; p=0.003). Only 19.2% regularly checked AQI, 36.4% used masks, and 30.4% avoided outdoor activity during severe smog. Conclusion: Asthma morbidity increased during periods of poorer air quality, while inadequate controller adherence was associated with a higher exacerbation risk. These findings support AQI-informed asthma planning and improved adherence during the smog season
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