Indoor air quality in Kazakh households: Evaluating PM_2.5 levels generated by cooking activities

The present study introduces a concentration estimation model for indoor inhalable fine particles (PM_2.5) during cooking activities in typical Kazakh houses, which are generally poorly ventilated with high emission levels. The aim of the present work is to identify factors influencing PM_2.5 concentrations during cooking and elucidate the mechanisms underlying the build-up and reduction of PM_2.5 concentrations. These are achieved through a methodology that combines PM_2.5 sampling, monitoring, and modeling to predict household PM_2.5 levels and estimate daily concentrations. Specifically, USEPA's IAQX v1.1 was employed to simulate the one-zone concept (kitchen) for concentrations related to cooking activities in several households. The results reveal that PM_2.5 concentrations varied between 13 and 266 μg/m³ during cooking activities. Factors such as kitchen size, air exchange characteristics, and the type of food and cooking style were identified as important, influencing the observed concentrations. The model accurately captured concentration trends (R > 0.9). However, certain predictions tended to overestimate the measurements, attributing to inaccuracies in selecting air exchange and emission rates. Cooking activities contributed to household air pollutant (HAP) PM_2.5 levels ranging from 9% to 94%. Notably, during the non-heating period of the year (corresponding to the warmer half of the year), the impact of cooking became more significant and was identified as a major contributor to indoor PM_2.5 concentrations. Conversely, during the heating period (i.e., the colder part of the year), outdoor PM levels and household ventilation practices played primary roles in regulating indoor air concentrations. This present study presents one of the initial efforts to assess household air pollutants in Central Asia, providing foundation and insights into the indoor air quality of Kazakh houses, where the understanding of indoor air quality remains limited. Future research recommendations include developing advanced models that account for individual activity patterns and specific house types for improved accuracy and representativeness.