Impact of daily household activities on indoor PM2.5 and Black Carbon concentrations in Malta

In this study we present the outdoor and indoor particulate matter (PM) and Black Carbon (BC) measurements in a typical terraced house, located in an urban area in the island of Malta. The influence of different household activities on the indoor PM2.5 and BC levels were also analysed. The activities resulting in elevated indoor concentrations included sweeping, cooking (not grilling and frying), grilling and frying and burning of candle and incense sticks. Sweeping resulted in the highest PM2.5 concentration (283.14 mu g m(-3)) while frying resulted in the lowest level (104.14 mu g m(-3)). Burning of paraffin wax candles resulted in the largest increases in indoor BC concentration (62.2 mu g m(-3)) while the lowest peaks corresponded to cooking and frying. We estimated average PM2.5 and BC emission rates for each indoor activity reaching 22.19 mu g s(-1) during sweeping and 2.46 mu g s(-1) during burning of paraffin candles and incense sticks and were sensitive to different ventilation rates. Given that people spend substantial time in the home environment, especially with a future where remote work is likely to be further facilitated, identifying the activities and sources which lead to elevated indoor pollutants is crucial to limit indoor exposure.