Temporal Variation and Sources of Particulate Matter in Kannur: Insights from a Coastal City in South India

Abstract

In this study, particulate matter (PM) variation has been analyzed to address the dearth of scientific research on air pollution in a coastal city from south India. Mean PM_2.5 and PM₁₀ concentrations were 61.6 ± 26.4 and 87.3 ± 35.4 μg/m³. The highest (lowest) seasonal concentration was observed during winter (monsoon). Increase in PM from September to February is attributed to low relative humidity, biomass burning in nearby paddy fields, and continental air mass from the east and north-easterly direction. The mean PM2.5/PM10 ratio was 0.71, with the seasonal ratio ranging between 0.64 (summer) and 0.76 (monsoon), indicating the dominance of anthropogenic PM fraction. PM exhibited typical characteristic of the urban region, i.e., a two-peak diurnal trend during all seasons except monsoon. PM₁₀ (PM_2.5) concentrations decreased by ∼7–24.2% (∼11–21%) on the weekends, with the highest reduction in winter seasons. Regarding correlation analysis among PM, CO, and ozone; a negative correlation between PM₁₀ and O₃ and a positive correlation between PM and CO was observed. Wind speed and PM₁₀ showed a positive quadratic linear, whereas wind speed and PM_2.5 showed a negative linear relationship. The primary sources of particulate matter in Kannur town are motor vehicle emissions, dust from construction work in surrounding zones, and nearby industrial units.

Keywords:

• Air pollution
• particulate matter
• temporal variation
• Kannur
• South India

Acknowledgment

The authors are grateful to the Indian Space Research Organization (ISRO), Bangalore and Kerala State Council for Science Technology and Environment (KSCSTE) for granting financial support to study air pollutants in the Kannur region. Prof. Valsaraj thanks the Charles and Hilda Roddey Distinguished Professorship funds through the LSU Foundation in support of this work.

Authors’ contribution

D.R.: Conceptualization, Visualization, Writing-original draft; K. A. K. L.: Writing-review & editing; F.Y.: Writing-review & editing; T. N.: Resources, Conceptualization, Writing-review & editing; M. G. M.: Writing-review & editing; R.S.: Writing-review & editing; M. K. S. K.: Writing-review & editing; K. T. V.: Writing-review & editing; J. H.: Writing-review & editing

Disclosure statement

Authors have no relevant financial or non-financial interests to disclose.

Data availability statement

Data will be made available on a reasonable request.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (42021004). Dipesh Rupakheti would like to acknowledge the Startup Foundation for Introducing Talent of NUIST (2022r024) and the Jiangsu Province “Double Innovation Doctor” Program (JSSCBS20220552).