Indoor air quality assessment in cinnamon oil refinery centres in Sri Lanka using PTM 600: identifying ventilation-related health risks

Abstract

This field-based case study assessed indoor air quality and ventilation-related occupational exposure conditions in a selected cinnamon oil refinery centre in Beruthuduwa, Galle, Sri Lanka. A preliminary questionnaire survey was conducted among 48 respondents from 12 refinery environments (24 workers, 12 owners and 12 community members), including questions on symptoms experienced during refinery operation. Detailed monitoring was then carried out at one selected refinery during one complete, approximately seven-hour cinnamon oil distillation cycle. A PTM 600 portable monitor was used at five repeated operational points and one supplementary elevated leaf loading point to measure CO₂, CO, SO₂, NO₂, O₃, VOC, PM₂.₅, PM₁₀, temperature and relative humidity; inlet and outlet air velocities were also measured. The highest CO process cycle mean occurred at the boiler zone (P2: 29.81 ppm), while the strongest particle levels occurred at the boiler and oil separator zones (PM₂.₅: 415 and 404 μg/m³ at P2 and P3; PM₁₀: 433 and 435 μg/m³ at P2 and P3). The supplementary leaf loading point identified a short-duration, task-based pathway for hot humid vapour and particles. Measured mean air velocity was approximately 2.20 m/s at the inlet and 0.23 m/s at the monitored outlet; these point measurements indicate a large local airflow difference but do not by themselves quantify overall ventilation effectiveness. Among workers, headache, eye irritation and cough were reported by 100%, nasal symptoms by 95.8%, and dry/sore throat by 62.5%. These self-reported symptoms were used as supporting evidence and do not establish pollutant-specific causality. The findings support source control at the boiler and vessel opening, improved exhaust pathways, safer leaf loading practices, personal protective equipment, worker rotation and follow-up monitoring.