Table 1.

Overview of cell models available for air pollution toxicology studies. Example model categories are listed alongside advantages and disadvantages towards the evaluation of toxicity associated with air pollutant exposures.

Cell Model Category	Advantages	Disadvantages
Monoculture cell lines	-Easy to grow and maintain -Inexpensive -Amenable to high-throughput screening -Reproducible toxicity responses -High viability in comparison to other models -Available for different cell types present in the respiratory tract -Availability/standardization allows for comparison of results among different groups	-From one donor, which does not account for population response variability -In cancer/transformed cell lines, genetic and epigenetic profiles differ from non-cancer cells -Depending on cell line, limited representation of an in vivo epithelial barrier -Findings are limited to one cell type
Cells from human donors	-Allows for evaluation of specific subpopulation of interest (e.g., age, disease, sex, etc.) -Allows for identification of cell populations with increased susceptibility to adverse effects -Improved physiological relevance -Evaluation of responses across multiple cell types -Can be maintained in culture for weeks/months at a time -Can be used for repeated exposures to simulate chronic conditions	-Expensive -Requires more advanced cell culture capabilities -Time and resource intensive to process and maintain cell culture -Difficult to determine which cell type drives observed toxicity
Lung-on-a-chip	-Improved physiological relevance due to potential cell-to-cell communications -Continuous replenishment of nutrients and removal of waste -Can model influence of circulating immune cells -Includes physical and mechanical properties involved in in vivo pulmonary functions -Can allow for organ-crosstalk (e.g., body-on-a-chip)	-Difficulties surrounding ease of use -Expensive -More chronic exposures are currently difficult due to viability considerations -Technologies are more recently developed and may require further testing -Insufficient biological material for downstream analyses