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Tiruttani occupies a distinctive position in northern Tamil Nadu, situated approximately 85 kilometres northwest of Chennai along the border with Andhra Pradesh. This pilgrimage town rests at an elevation of 76 metres above sea level on the eastern slopes of the Tiruttani Hills, part of the Eastern Ghats foothills, creating a transitional zone between the coastal plains and inland plateaus. The city's geography profoundly influences its air quality through multiple mechanisms. Located in the Palar River basin, Tiruttani lies within an agricultural belt dominated by paddy fields, sugarcane plantations, and mango orchards, with seasonal burning of crop residues contributing particulate matter. The urban-rural gradient is pronounced—while the town centre experiences concentrated pollution from pilgrimage traffic and construction, surrounding rural areas generate agricultural emissions. Proximity to major transportation corridors, including National Highway 716 and rail links to Chennai and Tirupati, ensures continuous vehicle emissions. The terrain creates microclimatic effects: the hills to the west can trap pollutants during calm conditions, while the open plains to the east allow some dispersion. Crucially, Tiruttani lies outside Tamil Nadu's major industrial belts, making its pollution profile distinctively dominated by religious, agricultural, and construction sources rather than heavy industry. The absence of significant water bodies nearby reduces natural cleansing through precipitation in dry seasons, while the town's position in the rain shadow of the Eastern Ghats during the northeast monsoon results in prolonged dry periods that exacerbate dust accumulation.

Tiruttani's air quality follows a pronounced seasonal rhythm dictated by its tropical wet-and-dry climate and pilgrimage calendar. The winter months from November through February represent the peak pollution period, coinciding with the pilgrimage season to the renowned Subramanya Swamy Temple. During these months, cool temperatures (averaging 20-25°C) combine with frequent temperature inversions that trap vehicle emissions, incense smoke, and construction dust near ground level. Light winds and morning fog further inhibit dispersion, creating hazardous conditions particularly for asthmatics, children, and the elderly who should limit outdoor temple visits. The summer season from March to May brings extreme heat (often exceeding 40°C) that increases ozone formation from vehicle emissions, though stronger afternoon winds provide some pollutant dispersal. This period sees reduced pilgrimage traffic but increased agricultural burning and road dust from dry conditions. The southwest monsoon from June to September dramatically improves air quality through heavy rainfall that washes away particulate matter, with July and August offering the cleanest air for outdoor activities. The shorter northeast monsoon from October to November brings moderate rainfall that initially suppresses pollution before the winter buildup begins. Sensitive groups should monitor local air quality reports particularly during temple festivals in December-January, when ritual smoke and traffic congestion peak, and consider wearing N95 masks in crowded pilgrimage areas.