Comparative ambient and indoor particulate matter analysis of operation theatres of government and private (trust) Hospitals of Lahore, Pakistan

The link between infection and indoor air quality (IAQ) in operating theatres is well established. The level of airborne particulate matter (PM) in operating theatres in Pakistan has not yet been studied comprehensively. Monitoring of both indoor (operating theatre) and outdoor concentrations of PM in both activity and non-activity time periods was done using a DUSTTRAK Aerosol Monitor (TSI Model 8520) and DRX Aerosol Monitor (TSI Model 8533) for 24 hours. Two hospitals in Lahore were selected: Services Hospital (government – site 1) and Shalamar Hospital (private – site 2). The highest concentration of PM was observed in the orthopaedic operating theatre at site 1 during working hours with an average concentration of 757(±540), 809(±58), 824(±585), 875(±586) and 970(±581) μg/m³ of PM<inf>1</inf>,PM<inf>2.5</inf>, PM<inf>4</inf>, PM<inf>10</inf> and PMTotal respectively while the average PM<inf>2.5</inf> outdoor concentration was 294 μg/m³. The minimum average PM concentration was found in the orthopaedic operating theatre at site 2 during working hours: 18(±8), 19(±8), 20(±9), 26(±9) and 39(±9) μg/m³ for PM<inf>1</inf>, PM<inf>2.5</inf>, PM<inf>4</inf>, PM<inf>10</inf> and PMTotal respectively. The use of vertical laminar air flow ventilation strategy was found to be an effective measure in reducing PM levels and it might be possible to predict the air quality of operating theatres by determining PM dust load. Factors such as ventilation system, door opening /closing rates, building age, possible sources of infiltration, number of people present in the operating area all play a role in influencing PM concentrations in operating theatres.