Abstract/Summary

In today’s world, human activities have changed, with significant rise in individuals spending more time indoors including other enclosed spaces such as vehicles. Buildings have been extensively researched regarding their indoor environments (IEs). This, however, is not the case with vehicles, even though a substantial amount of time is spent in vehicles due to changes of workers commute patterns. With increased commuters since the Covid pandemic, understanding the IE of automobiles is vital as individuals are spending considerable time in vehicles. The aim of this research is to investigate the IE of vehicles with different fuel transmissions (i.e. petrol, diesel, and electric) and its impact on users. The methodology uses a questionnaire (non-heating and heating season) with an integrated Likert scale to determine the perception of vehicle users during different traffic conditions. 150 participants responded to the questionnaire. In addition, measurements (non-heating season) of PM2.5 and PM10 were collated for six vehicles of different fuel transmissions. The results from the questionnaire illustrate, in normal conditions, approximately 20% of participants experienced stress and tiredness most of the time, and 10% of individuals rarely experience these sensations. Experimentally, significant variation in pollutant concentrations in the vehicles for the different non-heating season and fuel transmission were observed. 75% of vehicles assessed exceeded acceptable guidelines for some of the monitored pollutants and reached elevated levels for CO2. Similarly, the air change rate (ACH) was significantly low in some vehicles, and combined with pollutants at elevated levels, this can be a reason as to why drivers’ felt stressed and/or tired. The findings presented in this research demonstrates the impact commuting has on the users of vehicles, regardless of vehicle transmission type. It also provides significant synergies noticed in buildings where the accumulation of carbon dioxide is proxy for poor indoor air quality.