## 3 Results
### Bibliometric Results
(2018) in a field study carried out in Poland, investigated whether climatic parameters (temperature, air pressure, humidity, wind speed, and precipitation) are related to the perception of fatigue by bus drivers in two situations (monotonous route and heavy traffic). As a result, the authors inferred that the route of intense traffic results in more fatigue more than the monotonous route. In addition, significant correlations were found between wind speed and the symptoms of heavy eyelids, forgetfulness, eye strain, frequent blinking, and between ambient temperature and thirst, on the monotonous route. However, for the intense traffic route, the ambient temperature was correlated with the sensation of thirst, tiredness, and decision-making difficulty, and the wind speed was correlated with the sensation of thirst. The year 2020 had the same performance as 2015 with four publications ([PERSON], [PERSON], and [PERSON], 2018; [PERSON], [PERSON], and [PERSON], 2018; [PERSON], [PERSON], and [PERSON], 2018) used computational fluid dynamics (CFD) and the PMV-PPD model to investigate three particular cases. In the first, the conditioning system vents in the buses were varied at four angles (\(0^{\circ}\), \(15^{\circ}\), \(30^{\circ}\), and \(45^{\circ}\)), in the second case, the authors chose the best vent angles and changed the air speed in two stages (from 1 to 2 m/s and from 2 to 3 m/s), and the third investigated an air conditioning system in which the outlet was rectangular and fixed without the possibility of angulation. However, the vent angle of \(30^{\circ}\) (PMV = +0.3 thermal neutrality and PPD = 5% thermally acceptable environment) and the speed of 3 m/s were considered the best setting in terms of airflow and temperature around the passengers. [PERSON] et al. (2018) investigated the effects of air pollution and temperature distribution on passenger comfort in an air-conditioned bus in China. As a result, the authors inferred that the passengers were in an environment with poor air quality due to ozone from the outside air and were thermally uncomfortable due to the high temperature. According to the authors, the effect of this thermal discomfort can be minimized by adjusting the system's vents to an angle of \(30^{\circ}\), the same angle recommended in the study by [PERSON], [PERSON], and [PERSON] (2018). [PERSON] et al. (2018) performed a field study in China to examine the effects of micro-environmental exposure (noise, air quality, temperature, relative humidity, and passenger load) and buses on passengers' moods. The result of this field study indicated that the ideal exposure levels for these microenvironmental indicators in the passenger cabin are 0 to 65 dB for noise, 22 to 28 \({}^{\circ}\)C for air temperature, 41% to 50% for relative humidity, and 18 to 19 for passenger capacity. In Turkey, [PERSON] (2018) conducted an experiment under controlled conditions in a climate chamber to assess the thermal comfort of passengers during a bus cooling process. In addition, the effects of rapid transient cooling conditions on the transfer of sensitive or latent heat from the body, on core and skin temperatures, and on thermal discomfort and sensation have been detailed. After 60 min of starting the bus' air conditioning system, the air temperature dropped from 40 to 28.8 \({}^{\circ}\)C and the relative humidity had no significant changes rising from 41% to 47%. The variation in the energy flow between the nucleus and the skin increased as the temperature dropped, since the body loses heat to the environment and, with this, the body generates heat in the nucleus and transmits to the skin to compensate the loss; thermal sensation dropped from \(-0.19\) (thermal neutrality) to \(-4.063\) (very cold) as the temperature dropped.