Assessment of Short-Term Air Quality Variations and Health Risk during Post-COVID Period using AQI Data

Abstract

The COVID-19 pandemic and subsequent lockdowns led to unprecedented improvements in urban air quality; however, the post-COVID period has been marked by a gradual rebound in pollution levels. This study assesses short-term air quality variations and associated health risks during the post-COVID period using Air Quality Index (AQI) data for Bhubaneswar, India. Hourly and daily concentrations of major criteria pollutants (PM?.?, PM??, NO?, SO?, CO, and O?) were analysed to examine temporal trends, short-term pollution episodes, and seasonal variability. The results indicate that post-COVID air quality predominantly ranged from moderate to poor, with pronounced deterioration during the winter and pre-monsoon seasons and comparatively improved conditions during the monsoon period. Short-term high-pollution episodes were frequent and persistent, driven mainly by particulate matter, leading to elevated AQI values and increased exposure risk. Health risk assessment based on AQI categories and international guideline thresholds suggests a heightened risk of respiratory and cardiovascular effects during poor and very poor air quality conditions. Comparative analysis across pre-COVID, COVID lockdown, and post-COVID phases reveals a substantial pollution reduction during lockdowns followed by a significant rebound in the post-pandemic phase. The findings underscore the importance of real-time AQI monitoring, early warning systems, and season-specific mitigation strategies to protect public health and support sustainable urban air quality management in post-pandemic cities.

Introduction

The study examines post-COVID short-term air quality fluctuations and associated health risks in Bhubaneswar, India, against the backdrop of global air quality improvements observed during COVID-19 lockdowns. Worldwide lockdowns significantly reduced anthropogenic activities such as transportation, industrial operations, and energy consumption, leading to temporary declines in major pollutants like PM?.?, PM??, NO?, SO?, and CO. However, as restrictions eased, pollution levels rebounded, highlighting the need for sustainable emission control strategies.

Despite extensive research on lockdown-related air quality improvements, limited studies have examined short-term AQI fluctuations in the post-COVID period and their direct linkage to acute health risks. This study addresses that gap by analyzing daily and seasonal AQI variations, identifying high-pollution episodes, and linking AQI categories to potential respiratory and cardiovascular impacts.

Key Findings

1. Post-COVID AQI Trends (Bhubaneswar):

   • Mean AQI: 132 ± 38 (Moderate–Poor)

   • Winter recorded the worst air quality (162 ± 41), while monsoon showed the lowest levels due to rainfall-driven pollutant washout.

   • Clear seasonal dependence indicates strong meteorological influence.

2. Short-Term Pollution Episodes:

   • Peak AQI reached 312 (Very Poor).

   • PM?.? and PM?? were dominant contributors.

   • Episodes lasted 9–11 hours on average, with some extending beyond 30 hours.

   • Most events occurred during winter and pre-monsoon periods.

3. Health Risk Assessment:

   • Moderate AQI affects sensitive groups.

   • Poor and Very Poor categories are associated with aggravated asthma, reduced lung function, and increased hospital admissions.

   • Short-term spikes pose significant acute health risks.

4. Comparative COVID Phase Analysis:

   • Pre-COVID AQI: 158 ± 42 (Poor)

   • Lockdown AQI: 94 ± 26 (−32%, Satisfactory)

   • Post-COVID AQI: 132 ± 38 (+40% from lockdown)

   • Indicates partial pollution rebound, though not fully returning to pre-pandemic levels.

Conclusion

This study assessed short-term air quality variations and associated health risks during the post-COVID period using AQI and pollutant concentration data for Bhubaneswar, India. The findings reveal a clear rebound in urban air pollution following the relaxation of COVID-19 restrictions, with overall air quality ranging from moderate to poor. Seasonal analysis highlights pronounced temporal variability, with winter and pre-monsoon periods emerging as the most critical phases due to frequent high-pollution episodes and unfavorable dispersion conditions, while monsoon months exhibited comparatively improved air quality. Short-term pollution episodes were characterized by high intensity and multi-hour persistence, primarily driven by particulate matter (PM?.? and PM??), underscoring their dominant role in shaping AQI variability and public health risk. The health risk assessment indicates that prolonged exposure during poor and very poor AQI conditions may significantly aggravate respiratory and cardiovascular outcomes, particularly among vulnerable population groups. Comparative analysis across COVID phases demonstrates that while lockdown-related improvements were substantial, they were largely temporary, with post-COVID pollution levels approaching pre-pandemic conditions.

References

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Copyright

Copyright © 2026 Aditi Patnaik, Indira Priyadarshini Padhy, Amiyajyoti Nayak. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.