How Do Indoor Activities Affect Indoor and Outdoor Air Quality?

Abstract:

Even though more than 90 % of our time is spent indoors, most atmospheric chemistry research is focused on outdoor air. The chemistry of indoor air is different from outdoors, with different sources of pollutants, lower photolysis rates, and much higher surface area to volume ratios. Although detailed investigations of indoor air chemistry have become more abundant in recent years, the complexity of indoor environments makes it a challenging system to describe. Indoor air chemistry models can be useful tools to understand the chemistry in the absence of observational data or to provide further insight when used alongside measurements, particularly when such measurements are made in realistic indoor environments.

Here, we use the Indoor Detailed Chemical Model (INDCM) to describe the impact of indoor cooking and cleaning activities on indoor air chemistry and then also on outdoor air following the opening of a window. The INDCM uses the near-explicit chemical scheme of the Master Chemical Mechanism v. 3.3.1 (MCM) comprising of ~ 17,000 reactions and 6700 species. The model has been initialised with data from the House Observations of Microbial and Environmental Chemistry (HOMEChem) field campaign, where air composition was measured while different activities were carried out in a test house during the summer of 2018. Cooking, cleaning and background conditions are simulated in the INDCM and predicted indoor radical concentrations compared with measurements. The ‘aged’ air is then released outdoors assuming Gaussian dispersion, with the window assumed to be a point source for outdoor air.

The results from this study will then be used to assess the importance of indoor air chemistry processing for indoor and outdoor air composition for air quality.