Quilon, officially known as Kollam, occupies a distinctive coastal position in Kerala's Malabar region, situated at the southern end of the Ashtamudi Lake—a sprawling brackish water lagoon that profoundly shapes its urban character and environmental dynamics. The city's geography is defined by its location at approximately 8.8932°N latitude and 76.6141°E longitude, nestled between the Arabian Sea to the west and the Western Ghats mountain range to the east, creating a unique microclimate that influences air quality patterns. With an elevation near sea level, Quilon's terrain transitions from coastal plains to gentle inland slopes, supporting both urban development and lush agricultural zones, particularly coconut plantations and paddy fields that surround the city. This urban-rural gradient means pollution sources are mixed: general urban emissions from transportation and residential activities blend with occasional agricultural burning and natural sea salt aerosols. The city's position along the Ashtamudi Lake, one of Kerala's largest wetland ecosystems, provides natural ventilation that typically disperses pollutants, though during certain seasons, the lake's moisture can contribute to haze formation. Proximity to the Arabian Sea brings regular sea breezes that generally improve air quality, but the city's location in a densely populated region of South Asia means it's not immune to regional pollution transport, especially from nearby urban centers and occasional industrial activities in the industrial belt extending towards Kochi. The surrounding landscape of backwaters and low-lying areas can trap pollutants under specific meteorological conditions, particularly during pre-monsoon months when atmospheric stability increases.

Quilon's air quality follows a distinct seasonal rhythm shaped by Kerala's tropical monsoon climate, with pollution patterns closely tied to meteorological shifts throughout the year. During the pre-monsoon season from March to May, rising temperatures and reduced wind speeds often lead to atmospheric stability, allowing pollutants from urban activities and occasional agricultural residue burning to accumulate, making these months less favourable for outdoor exertion, especially for sensitive groups like those with respiratory conditions. The southwest monsoon from June to September brings heavy rainfall that dramatically cleanses the air, washing away particulate matter and reducing pollution levels to their annual troughs—this period offers the best conditions for outdoor activities, though high humidity may pose challenges for some individuals. Post-monsoon months from October to November see gradually improving air quality as rains recede but before winter stagnation sets in, with pleasant weather making this an ideal time for visitors and residents to enjoy outdoor pursuits. The northeast monsoon from December to February brings cooler temperatures and moderate rainfall, but occasional temperature inversions and fog, particularly in early mornings, can trap pollutants near the surface, creating brief episodes of reduced air quality that vulnerable populations should monitor. Throughout the year, sea breezes from the Arabian Sea provide natural ventilation, but during transition periods between monsoon seasons, wind patterns can become variable, sometimes allowing regional pollution to affect local air quality. Sensitive groups should be particularly cautious during the pre-monsoon heat and winter inversion periods, staying informed about local air quality reports and limiting prolonged outdoor exposure during noticeable haze episodes.