From various other studies, it is known that the maximum carbon dioxide concentration in different countries is between 1,000 ppm up to 1,500 ppm. Therefore, the research is focused on indoor environment, namely the production of pollutants from the persons inside office rooms. The article presents the trend of the carbon dioxide concentration from the occupants inside an office. It is examined the carbon dioxide production separately for men and women, for persons of different mass and for persons of different ages. It is also analyzed the carbon dioxide production during a sedentary and physical activities. In parallel with the production of carbon dioxide is presented the monitoring of the human pulse and blood pressure. All these parameters are monitored together with relative humidity and indoor air temperature. The aims of this paper is to describe the partial results of human respiration impact on indoor air quality in closed spaces and to research the connection between carbon dioxide concentration and human health.

The presented research work is aimed at investigation of the influence of indoor environmental conditions on employees in office buildings. Monitoring of carbon dioxide, temperature, relative humidity and pulse, as well as subjective evaluation, was carried out in three office rooms where air conditioning systems ensured the required amount of fresh air. Investigation showed that in two offices (A and B), the amount of fresh air did not comply with EN 15251:2017. The concentration of CO₂ in office A was above 1000 ppm for 72% of the total length of stay. Respondents confirmed fatigue and headaches. In offices A and B, where CO₂ concentration was around 1000 ppm, people with a weight of up to 70 kg experienced a significant increase in air temperature as well as odor. Persons with weight higher than 75 kg experienced a slight decrease in air quality. In office C, where CO₂ concentration was around 800 ppm, respondents reported a slight decrease in air quality. According to pulse monitoring, it can be stated that in an office where there is an insufficient supply of fresh air, the pulse of a person falls or only slightly rises. A decrease in pulses may indicate the attenuation or stunning of people caused by poor air quality.

The aim of the paper is to determine a methodology for calculating the needed airflow rate (including fresh air) in an occupied room, based on carbon dioxide measurement and calculation, in order to maintain the comfort indoor air quality. The calculated airflow rate should optimize the investment and the operating costs of HVAC equipment. In the work there are analyzed the calculation methods used to determine the ventilation airflow rate. It is presented the methodology for calculating the ventilation airflow rate for a room with people inside by using the measured values of carbon dioxide concentration. The connection between carbon dioxide concentration and ventilation airflow rate is verified by experimental measurements. This methodology is applicable in Slovakia because it complies with all current standards. The result obtained by using this calculation method is almost the same with that achieved from experimental measurements. To confirm the results, it is presented a case study of an office with occupants, in which the ventilation airflow rate calculation method is applied.In the article only a part from the total work is presented. The experimental measurements were carried out from 2011 to 2014. Approximately 54 measurements were covering total days or weeks. The following factors have been measured: indoor air temperature, outdoor air temperature, relative humidity of indoor air, relative humidity of outdoor air, concentration of CO2 in indoor air, concentration of CO2 in outdoor air, pressure difference and wind velocity. Ventilation by infiltration was calculated based on these factors using several methodologies. The methodology of measurement is not subject to the article. In this article only one aspect is investigated: CO2 concentration

In the construction process of modern buildings, the aim is to achieve maximum comfort within minimum energy consumption. One of the ways to achieve this requirement is the accurate determination of the volumetric flow rate of fresh air, necessary to ensure the required indoor air quality. This study begins with the experimental determination of carbon dioxide (CO₂) concentration in an office room with one occupant performing three types of activities with different levels of physical intensities. Based on these measurements, a methodology for the precise determination of the volumetric air flow rate is presented. This method was compared with another one that takes into account body parameters and is considered in this study as the most accurate. The required outdoor air flow rate for the experimental room was also determined based on the present legislations of five different countries. Comparing all the studied methods and considering as refence the method based on body parameters, it was found that the accuracy of the values is influenced by the physical intensity of the activity and that most methods generally underestimate the amount of required fresh air.

This paper presents a device for introducing air inside a room with the novelty of double-exponential profile of the distributor. This allows entering the rooms of large quantities of blow-in air with low velocities, with the result of possible use in locations with a high required air exchange. In the Laboratory of Ventilation and Air Conditioning of the Technical University of Cluj-Napoca, it was designed and built an experimental stand in order to investigate the velocity field of a double-equal strength (double exponential profile) inlet device for spatial air-distribution. There are presented the measurements that were performed in the laboratory in order to establish the velocity field and the spatial distribution of air. The proposed solution can be used in many applications to provide high rates of air through the ventilation systems.

In order to design a ventilation system based on the volumetric airflow rate, which will ensure satisfactory indoor air quality and, at the same time, do not oversize the system, it is necessary to know the quantities of pollutants emissions. The concentration of produced pollutants allows the calculation of the required fresh air volumetric flow rate. Two previous published studies are analysed in this article, whose results complement each other. From the calculated values, the graphical dependence between the required fresh air volumetric flow rate and the level of physical activity was developed. It was noticed that, according to the Slovak and Romanian legislation, for the studied gym, there is insufficient air ventilation. At an allowed maximum CO2 concentration level of 1,000 ppm, the required fresh air volumetric flow rate, according to legislative requirements, will ensure a percentage of only 75.59% to 23.25% of the necessary rate (depending of the type of physical activity). For a lower allowed maximum CO2 concentration level, the ensured fresh air volumetric flow rate will be even smaller. The aim of the article is to contribute to the development of healthy environments in fitness centres and gyms and to optimize the design requirements for their