Comparative analysis of PM2.5 levels in various microenvironments associated with common cooking practices in selected Asian countries

Effects of real-life cooking activities on PM_2.5 in different urban microenvironments of crowded and large metropolitan areas in Asia were comprehensively analyzed. The assessment was done based on monitoring data obtained for commercial cooking in a university campus in Thailand, restaurants in Taiwan, street food vendors, and residential cooking in Vietnam. Online instruments used for PM_2.5 monitoring were priori calibrated against the reference equipment. The influence of cooking activities on indoor and outdoor PM_2.5 levels was evaluated considering ventilation conditions and the type of fuel-cookstove of liquefied petroleum gas (LPG), charcoal, rice straw pellets (RSP), and honeycomb coal briquettes (HCB). Higher levels of PM_2.5 were observed during intensive cooking periods than in non-cooking periods. Cooking with solid fuel (RSP, charcoal, and HCB) induced higher exposure levels of PM_2.5 than LPG. The fuel stoking practice, size and design of stoves (with or without hood/exhaust fan), and type of food being cooked (steaming or meat grilling) were important factors affecting the PM_2.5 levels. Other important factors especially affecting indoor PM_2.5 levels included ventilation, outdoor emissions (traffic, nearby cooking activities), indoor sources (number of customers), and incense burning. The ambient pollution in the surroundings of the microenvironments may contribute significantly to measured PM_2.5 levels, especially for the locations close to busy roads or in areas with heavy traffic. Further studies are required to assess the impact of exposure to cooking-induced PM_2.5 emissions on human health to provide scientific evidence to foster clean cooking practices.