This study was conducted in an urban park in a temperate-continental city of Europe (Timișoara, Romania) and aimed to investigate the contribution of urban vegetation in maintaining air quality and mitigating the heat in the analyzed city. The following air parameters were monitored: fine particulate matter PM_2.5, coarse particulate matter PM₁₀, AQI (Air Quality Index) (resulted from PM_2.5 and PM₁₀), particle number, air temperature, relative air humidity, TVOC (total volatile organic compounds), and HCHO (formaldehyde). The results of this study show that urban vegetation remains a reliable factor in reducing PM_2.5 and PM₁₀ in city air and in keeping the AQI within the limits corresponding to good air quality, but also that relative air humidity counteracts the contribution of vegetation in achieving this goal. Inside the park, the HCHO concentration increased by up to 4–5 times compared to the outside, and this increase was not caused by vehicle traffic but rather by the photochemical reactions generating HCHO. Regarding the cooling effect on air temperature, the studied green space did not exhibit this effect, as the air temperature inside it increased by up to 1–6 °C compared to the outside. Our results contrast with the general perception that urban parks and green spaces are cooler islands within the cities and draw attention to the fact that having a green space in a city does not necessarily mean achieving environmental goals, such as reducing the heat risk of cities. Based on the results, we consider that the main limitations in achieving these objectives were the park’s small size (88 hectares) and its morphology and architecture resulting from the integration of the species that compose it. It follows from these data that it is not enough for an urban green space to be established, but its design must be combined with urban morphology strategies if the heat mitigation effect is to be achieved and the cooling benefits are to be maximized in cities.

This study was conducted in a temperate-continental city of Europe (Timișoara, Romania) and aimed to investigate the contribution of urban vegetation in maintaining air quality and mitigating the heat in the analyzed city. It was studied The Central Park „Anton von Scudier” located in the downtown of Timișoara City (45°45′05″N, 21°13′16″E) for the following air parameters: fine particulate matter PM2.5 (aerodynamic diameter < 2.5 μm), fine particulate matter PM10 (aerodynamic diameter < 10 μm), AQI (Air Quality Index) (resulted from PM2.5 and PM10), particles number, air temperature, air relative humidity, TVOC (total volatile organic compounds), HCHO (formaldehyde). Nine sample points of air monitoring were established: seven inside the green space and two outside it. The air monitoring was done in the late August, in four consecutive working days (Monday-Thursday), within 12:00-14:00 a.m. The air measurements were made using a portable device for outdoor air monitoring (Temtop LKC-1000 Series Air Quality Monitor). The results of this study show that urban vegetation remains a reliable factor in reducing PM2.5 and PM10 in cities air and in keeping the AQI within the limits corresponding to good air quality, but also that air relative humidity counteracts the contribution of vegetation in achieving this goal. Thus, the study highlights the importance of air humidity in enhancing the values of PM2.5, PM10, AQI, and in exceeding their admissible or recommended limits for air quality. There was not confirmed by this study the effect of wet deposition of the airborne particles as effect of precipitations. Inside the park, the HCHO concentration increased by up to 4-5 times compared to the outside, and this increase was not caused by vehicle traffic, but rather by the photochemical reactions generating HCHO. Regarding the cooling effect on air temperature, the studied green space did not exhibit this effect, as the air temperature inside it increased by up to 1-6°C compared to the outside, which means it did not achieved its goal of providing climatic comfort to citizens during the summer and serving as a cooling spot in the city. Our results contrast the general perception and conviction that urban parks and green spaces are cooler islands within the cities and draw attention to the fact that having a green space in a city does not necessarily mean achieving environmental goals, such as reducing the heat risk of cities. In this study, based on the results, we consider that the main limitations in achieving these objectives were the park’s small size (88 hectares) and its morphology and architecture resulting from the integration of the species that compose it. It follows from these data that it is not enough that an urban green space to be established, but its design must be combined with urban morphology strategies if the heat mitigation effect is to be achieved and the cooling benefits are to be maximized in cities. Therefore, in the urban planning, the environmental strategies should comprise not only aesthetic criteria, but also scientific criteria in order to reach the final goal of the urban green spaces in the cities: a sustainable, healthy, and comfortable environment.

The assessment of the degree of accessibility of urban green spaces for the population of the city of Timișoara (Romania) was carried out by taking into account the recommendations of the World Health Organization (WHO). These recommendations address the proximity accessibility of urban green spaces, operationalized through two main indicators: (1) proximity accessibility defined through two metrics–spatial distance and walking time between urban green spaces and residents’ dwellings; and (2) proximity accessibility defined by the area of urban green space available per urban resident capita. Based on the distance and walking time between residential areas and urban green spaces, accessibility classes were established, according to which the city’s green spaces were classified into distinct categories. Even under a simplified Euclidean centroid-to-centroid approach, the measured distances of urban green space accessibility exceed the World Health Organization’s recommended 300 m threshold for optimal access by a factor of 2 to 9 in the city of Timișoara. The measurements showed that none of the 48 studied neighborhoods of the city of Timișoara benefits from access to a public urban green space located at a distance of less than 200 m from the dwelling, according to the classification used in this study, and that only a single neighborhood has access to a public urban green space located at a distance of up to 300 m, as recommended by the WHO. The analysis indicated that for each resident of the city of Timișoara, an area of 8.4 m² of urban green space is allocated, a value below the WHO recommendation of 9 m² and below the legal threshold of 26 m² established by Romanian national legislation. Consequently, the city of Timișoara does not meet either the values established by national legislation or the authoritative international recommendations (WHO) regarding the standard of urban green space per capita, nor the accessibility criteria expressed as distance and walking time from residents’ dwellings to the nearest public urban green space. The results of the study show that, in relation to international standards and national obligations, Timișoara faces a severe deficit of urban green space, which affects the ecological, social, and health functions of the city. The obtained values highlight both a quantitative problem and a structural one, characterized by an uneven distribution and reduced accessibility of green spaces in most neighborhoods, with green spaces concentrated in the central area and limited access for many residents. This situation underscores the need for a strategic reconfiguration of urban policies, oriented toward increasing green capital and ensuring balanced, sustainable urban development aligned with contemporary standards. Urban policy implications include the strategic development of new green spaces in underserved neighborhoods, the establishment of pedestrian and green corridors to reduce travel time, and the redesign of pedestrian connectivity to major parks. These interventions would help reduce territorial inequalities and strengthen the city’s resilience.