Study of exposure to Particulate Matter during daily commuting - understanding from Tezpur city of mid-Brahmaputra Valley, India.

The small cities in South Asian that grow out of district headquarters generally lack adequate public transport and so commuters often have to walk or wait long hours at the bus stands and getting exposed to elevated levels of particulate pollution. People spend considerable time in walking, waiting at bus stand, and travelling in bus daily for job. This study was taken up to estimate personal exposure of particulate matter (PM) (PM₁₀, PM_2.5, and PM₁) in different exposure situations such as waiting at bus stand, inside bus, and walking through downtown. The measurements of the PM were carried out by an aerosol spectrometer (GRIMM, Model 1.109). The PM concentrations varied against commuting situations. PM exposure doses for 30 min were found to be high for situation walking through downtown (57 µg (PM₁₀), 25 µg (PM_2.5), and 20 µg (PM₁)) compared to situations waiting at bus stand and travelling inside bus. The highest hourly average concentration of inhalable, thoracic, and alveolic particles were 473 µg/m³, 282 µg/m³, and 126 µg/m³ during winter season while waiting at bus stand.These high, acute exposures emphasized the limited human resilience and highlight the critical need for targeted, localized air quality interventions for daily commuters. This study is relevant in appreciating repeated and periodic short-term exposures of PM on a daily basis for a lifetime of the commuters which is not otherwise taken into consideration in the policymaking.