Air Quality in Apartments
Indoor air quality is an important aspect of healthy living, especially during COVID-19 restrictions, when we spend most of the day indoors, exposing ourselves to pollutants. The poorer the quality of the air and the higher the number of dispersed particles, the more chance there is that the virus will spread.
On the other hand, ventilation is a major factor accounting for heat loss. When rooms are aired, heat goes out through the window giving way to the cold outdoor air, which must be warmed up to a temperature acceptable for people. But how do we know that there is enough ventilation of sufficient quality, ensuring the required levels of air exchange?
During the last heating season February to May 2022 the Riga Energy Agency (REA) conducted air quality measurements in multiapartment buildings in Riga within the framework of the European Union innovation and research programme Horizon 2020 project "Artificial Intelligence for Next Generation Energy (I-NERGY)".
More particularly, the air quality measurements were conducted in 4 different buildings in Riga: two of them located in the district of Purvciems and the other two in the districts of Mezciems and Jugla. Three of the buildings have undergone renovation, while the remaining one has not been renovated. The buildings were fitted with indoor air quality and outdoor microclimate monitoring equipment or sensors connected to a cloud sensor data exchange and analysis solution platform www.energodati.lv. Residents were able to connect to the data portal and follow the air quality indicators in their apartment.
More particularly, each building had air quality measuring sensors installed in the apartments performing measurements of the apartment area at 12-minute intervals and sending the data to a central database. Each sensor took the measurements of carbon dioxide (CO2), relative air humidity, and temperature. The sensors were placed in the living rooms, where people spend most of their time and there are no other factors affecting sensor readings, such as direct sunlight on the windowsill or fumes in the kitchen. It is worth mentioning that none of the buildings evaluated have any mechanical ventilation system installed.
The aim of monitoring was to obtain high reliability real-time data on indoor air quality and microclimate in multiapartment buildings depending on their renovation status. The data were evaluated in correlation to the heat consumption and climate conditions in the range of each building.
Air Quality is Poorer in an Unrenovated Building
Based on the measurements, it can be observed that all the apartments of the unrenovated building had higher CO2 levels compared to those of a renovated building with a refurbished existing ventilation system.
Indoor Temperature Control by Opening a Window
Indoor temperatures in the unrenovated building were significantly higher than those in the renovated buildings with refurbished heat-supply systems and new radiators fitted with thermocontrol valves. The average indoor temperatures in the unrenovated building surpassed the temperatures in the apartments of the renovated buildings by 1.3—1.6 degrees Celsius. Since the radiators in the apartments of the unrenovated building are not equipped with thermocontrol valves, the residents can only control the indoor temperature by opening the windows.
It stands out with clarity that the unrenovated building has the highest heat consumption among all the buildings reviewed, since it has no additional insulation and its engineering systems, including the heat supply, hot water supply and ventilation systems, have not been refurbished. The excessive heat supply to the building results in wasteful heat consumption, which, according to the estimates made by the Riga Energy Agency, results in an annual cost of several thousands of euros for the residents. At the same time, the increased levels of CO2 in the indoor air point to the unsatisfactory functioning of the existing exhaust system.
Indoor air quality in apartments is an additional aspect that must be considered when reviewing the need for renovating an apartment house. Heat consumption in a building constructed during the Soviet times is higher because of the low heat-resistance of the envelope, i.e., the walls, the windows, and the other external structures, with higher heating and hot water costs. The heating systems of the buildings of the century before do not offer the possibility of adjusting the indoor temperature to individual requirements, which results in overheating, wasteful use of heat and high energy costs. Poorly maintained ventilation shafts in the individual apartments or multiapartment buildings do not provide for the venting allowing the right amount of air to escape which results in poor air quality in the apartments.