In cities, air pollution is one of the main problems that affect the biological systems and the quality of residents’ life (Lavrov et al. 2019; Jaung et al. 2020; Lavrov et al. 2021a). Aerotechnogenic pollution of the environment through rapid urbanisation that has led to increase in the number of vehicles is one of the strongest factors inhibiting the development of green infrastructure in the city (Fuller and Quine 2016; Ferreira et al. 2016; Çelebi and Gök 2018; Grodzinskaya et al. 2019; Vacek et al. 2020). The negative human impact is manifested in changes in physiological processes, restructuring of links and food chains, destruction of biotic groups, changes in functioning, degradation of natural biotopes and global changes in landscapes and climate (Cuinica et al. 2014; Azzazy 2016; Livesley et al. 2016; Pietras-Couffignal and Robakowski 2019). The area of contact and intensive gas exchange with the environment cause high sensitivity of plants to various pollutants (Cuinica et al. 2015; Livesley et al. 2016; Vieira et al. 2018). The most dangerous for the green areas of cities are excessive concentrations of aerophytotoxicants NH3, NOx (mixture of gases NO, NO2, NO3), SO2, formaldehyde, phenol, soot and heavy metals. Their sources of entry into the environment are industrial enterprises and motor transport (Nikolaevsky 1998; Miroshnyk 2018; Rao et al. 2014; Nowak et al. 2014; Vacek et al. 2020). Air phytotoxicants cause leaf burns, disruption of physiological processes in plants, toxic and teratogenic effects. Emissions from vehicles make up the bulk of all emissions into the atmosphere of megacities (especially NOx, CO). They enter the air in the surface layer, which reduces their scattering by winds and poisons most living organisms. The presence of narrow streets and tall buildings is an obstacle to scattering and also contributes to the accumulation of harmful air pollutants in urban air in the breathing zone of pedestrians and greenery (Pietras-Couffignal and Robakowski 2019; Voordeckers et al. 2021). Accumulating in the surface layer of the atmosphere, some components of exhaust gases are involved in photochemical reactions (Kiptenko and Kozlenko 2016; Livesley et al. 2016; Vieira et al. 2018; Vacek et al. 2020) and cause significant damage to plants and humans. Air in cities is characterised by high dynamism due to the movement of air masses in the horizontal and vertical directions. Low car operation indicators, fuel quality, road density and throughput also contribute to increase in air pollution, which leads to reduced speed, congestion and increased emissions of pollutants (Klebanova and Klebanov 2011; Van Wittenberghe et al. 2012). Air pollutants settle on the surface of soils and plants, and thus enter the trophic chains (soil–plant–animal–human) (Cuinica et al. 2014, 2015; Livesley et al. 2016; Leghari et al. 2018; Grodzinskaya et al. 2019).
In Europe, North America and China, tree species, herbaceous, including
Hazard indexes (HIs) of pollutants have been studied in 11 parks in Pakistan (Khan et al. 2016) and in Kyiv, where the concentration of heavy metals in soils increases with increasing traffic intensity (Grodzinskaya et al. 2019). The quality and characteristics of tree seeds have significantly deteriorated with the increase in the number of vehicles (Aliyar et al. 2020; Vacek et al. 2020). Results of 18-year monitoring of
Possibilities of using a geographic information system (GIS) for the analysis of pollutant emissions into the atmosphere from transport are considered (Lee et al. 2006; Khan et al. 2016; Żak 2017). The high level of air pollution in Kyiv as one of the consequences of urbanisation poses a threat to public health and the natural environment. The main source of air pollution in Kyiv is motor transport – 86% of emissions or 144.3 thousand tons per year (Kiptenko and Kozlenko 2016; Ecological passport 2020). In 2019, 22.3 thousand tons of pollutants and greenhouse gases or 26.7 tons per 1 km2 were released into the atmosphere of Kyiv. Also, 7.5 kg of pollutants were emitted per person in the city. The highest level of air pollution (2.0 MAC and above) with phytotoxicants NOx, SO2, formaldehyde, and heavy metals causes a catastrophic state of street greenery (necrosis, leaf dechromation, significant defoliation of the crown, drying of trees). The total emissions of the most dangerous substances for park plantings in the air of Kyiv in 2019 were: dioxide and other sulphur compounds – 12.6 thousand tons, nitrogen oxides – 31.9 thousand tons and dust – 7.5 thousand tons. The general level of air pollution in Kyiv is estimated to be more (Ecological passport, 2020). Soils with heavy metal content are highly contaminated (Grodzinskaya et al. 2019). Thus, air pollution in the metropolis has become one of the most important problems, as the man-made load on the city's ecosystems has a dangerous rate and form. The climate of the metropolis contributes to the negative impact of air pollution on urban ecosystems, biodiversity, comfort and public health. Ecological and microclimatic zoning of Kyiv urban area indicates climate change (decrease in humidity, increase in temperature inside the city compared to its surroundings [about 5°C]) and the formation of temperature inversions and prevailing winds, typical for megacities – dominated by southern (17.4%), northern (16.8%) and western (16.7%) winds. Northwest and southwest winds have an average of 11% (Shevchenko and Snizhko 2008; Weather archive). Annual amount of precipitation decreased by ~10%. Due to the effect of climate decontinentalisation in the 20th century on the territory of Ukraine, in particular, significant warming in the summer months (July–August) has been proved, and over the last 45 years, there has been a significant decrease in precipitation by ~15% in April–May and July (Boychenko et al. 2017). Bioindication studies in the anthropogenic load gradient of Kyiv were performed (Rabosh and Kofanova 2019; Miroshnyk 2018; Mazura et al. 2020). Because greenery is important for maintaining air quality and microclimate in cities (Jaung et al. 2020; Jin et al. 2021; Wei et al. 2021), it is important and necessary to comprehensively study the viability of park ecosystems (PEs) under anthropogenic pressure. That is why we chose Kyiv city – as a landmark – because it is the largest city in the country with a population of 3 million people. However, there have been no comprehensive studies using a variety of integrative bioindicators and reflecting the impact of air pollution from motor transport. Therefore, the purpose of the study was to assess the impact of vehicle emissions on the state of PEs in the metropolis (Kyiv) using bioindication and GIS technologies.
PE was investigated in 2018–2020 on the Kyiv territory. The state of PE was assessed with the principles of comparative ecology (Anuchin 1982). The spatial structure, species composition and sanitary condition of the stand by tiers were studied on temporary trial plots (TPs) (not less than three TPs in each ecosystem, area 0.2–0.6 ha) in the middle-aged and ripening plantations (Anuchin 1982; Monitoring and increasing the resilience of anthropogenically disturbed forests 2011; Sanitary rules in the forests of Ukraine 2016). The degree of damage for mixed stands was assessed by the weighted index of stand state ( N – the total number of evaluated trees in the TP, individuals.
Stands with an index of 1.00–1.50 were considered healthy (no damage), 1.51–2.50 (weak damage) weakened, 2.51–3.50 (average damage) severely weakened, 3.51–4.50 (severe damage) wilting and 4.51–6.00 (the damage is very strong) dead (Monitoring and increasing the resilience of anthropogenically disturbed forests 2011).
The names of the families are given according to the system of Takhtajan (2009). The grass tier non-native plant index ( the relative number of species or guilds N – id the total number of individuals (number of individuals per hectare).
Pollen indication was performed according to
Pollen sterility (
The mean error was calculated as:
The sterility index ( CID – a conditional indicator of damage caused by adverse environmental conditions for each PE,
This approach makes it possible to perform an integrated assessment of the environment and determine the levels of environmental hazards to humans and biota (Kudryavska, Dychko, 2013). If the sterility of
The indicator of teratomorphism (
The average values of the characteristic (
We proposed an integral indicator of the impact significance (
The following environmental indicators ( 1) in the presence of visual signs of grass tier digression, to characterise the integrity of the ecosystem and tiers – projective grass cover ( 2) in the presence of seedlings of major and associated tree species, to assess the ability of the stand to natural regeneration (
The index of structural diversity of PE (
We calculated the size of the class interval for the indices by equation (9) (Zaitsev, 1990):
The level of air pollution of the metropolis from vehicles was determined on the basis of the calculation presented in Methods for determining vehicle emissions for summary calculations of urban air pollution (1999) using the service videoprobki.ua and own videos of traffic. The road load (number of cars per hour) and the average daily amount of emissions of harmful substances (NOx, hydrocarbons [C
The hazard factors of air pollutants were determined by equation (10):
MACs of air pollutants were established by Ukrainian legislation as the reference value for the national criteria (Order of the Ukraine ministry 2020). Cumulative risk, that is, the probability of developing a harmful effect due to the simultaneous entry of chemicals with a similar mechanism of action into living organisms by all possible routes (Environmental Protection 2005), was determined using the HI; for conditions of simultaneous entry of several substances in the same way (e.g. from air pollution),
The data were statistically evaluated following the method of Zaitsev (1990) and using Statistica 10, Microsoft Excel. To build a map of the city, we used a GIS package Golden Software Surfer 19.2.213 with the method of kriging and QGIS 3.16.3. The data were examined for normality using the Student's
Kyiv is the largest city, capital, industrial, scientific and cultural centre of Ukraine, located in the centre of Eastern Europe, in the north of Ukraine and on the border of Polissya and forest-steppe zone on both sides of the Dnipro River. The area of the city is 836 km2, including the green zone (460 km2 or 55%), water areas (62 km2, 7%), artificial urban ecosystems (314 km2, 38%) and built-up lands of the city (364.0 km2, 43.5%) (A regional report…, 2016). The territory of Kyiv is characterised by a complex relief, in the conditions of which air masses with a high concentration of pollutants are formed (Fig. 1). Most of the city lies on the high right bank of the Dnipro, and the Kyiv plateau is cut by a net of ravines (Babyn, Voznesensky, Protasov and others). Characteristic forms of the relief on the right bank are mountains-remnants. The smallest part is on the lower left bank of the Dnipro. The lower parts of Kyiv (left bank) correspond to the water level in the Dnipro and make up about 92 m of the altitude (Ecological passport, 2020). On the right bank of Kyiv, the height above the sea level is about 144–181 m and above (Fig. 1). The city has a powerful system of green infrastructure and objects of the natural reserve fund.
The system of ecological indicators of the PE state is built on the basis of indicators of the state of PE (
The value of integrated indices (environmental indicators) of the PE state
Index | W | Ic | Inv | Concentration NOx, mg/m3 | HI | |
---|---|---|---|---|---|---|
Very good | >2.47 | 9.26–12.00 | 1.00–1.50 | >8.67 | <0.020 | <1.060 |
Good | 2.21–2.46 | 6.51–9.25 | 1.51–2.50 | 5.79–8.67 | 0.021–0.040 | 1.061–2.121 |
Satisfactory | 1.97–2.20 | 3.76–6.50 | 2.51–3.50 | 2.90–5.78 | 0.041–0.060 | 2.122–3.181 |
Bad | <1.96 | 1.0–3.75 | 3.51–4.50 | <2.89 | 0.061–0.08 | 3.182–4.242 |
Very bad | – | – | 4.51–6.00 | – | >0.081 | >4.242 |
The studied PEs and suburban forests of Kyiv are formed mainly by deciduous species, less often by
The
Species saturation of the grass tier was 3.0–202.3 pieces/ha (most common were
Integral assessment of the studied park ecosystems state in Kyiv
Assessment indicators/No. PE | 1 | 2 | 3 | 5 | 6 | 7 | 9 | 10 | 12 | 14 | 15 | 16 | 17 | 18 | 19c | 20c |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Park area [ha] | 19.5 | 8.9 | 6.5 | 11.7 | 130.0 | 137.0 | 120.0 | 66.1 | 112.0 | 18.4 | 11.7 | 150.0 | 13.9 | 4525.5 | – | – |
Canopy density ( |
0.70 | 0.50 | 0.82 | 0.53 | 0.90 | 0.70 | 0.64 | 0.52 | 0.50 | 0.81 | 0.80 | 0.77 | 0.41 | 0.95 | – | – |
Index of stand state ( |
2.2 | 2.03 | 1.9 | 2.5 | 1.96 | 2.4 | 1.95 | 2.4 | 2.3 | 1.7 | 2.37 | 2.25 | 2.19 | 1.99 | – | – |
Sanitary condition of plantations | weakened | weakened | weakened | severely weakened | weakened | weakened | weakened | weakened | weakened | weakened | weakened | weakened | weakened | weakened | – | – |
Mortality of trees ( |
19.84 | 20.83 | 10.81 | 35.80 | 40.20 | 18.59 | 11.90 | 30.70 | 10.53 | 25.00 | 9.77 | 35.71 | 9.46 | 10.7 | – | – |
Species saturation of grass tier, pieces/ha ( |
92.86 | 42.50 | 67.57 | 202.27 | 55.88 | 34.62 | 117.86 | 171.05 | 126.32 | 42.31 | 39.66 | 80.43 | 3.24 | 30.3 | – | – |
Nitrophils in grass tier ( |
51.43 | 56.25 | 65.22 | 41.46 | 64.71 | 50.00 | 42.86 | 43.28 | 46.81 | 52.38 | 63.64 | 58.97 | 53.49 | 50.00 | – | – |
H′ | 2.86 | 1.97 | 2.51 | 3.60 | 2.01 | 2.23 | 2.15 | 3.30 | 3.11 | 2.37 | 2.46 | 3.07 | 3.65 | 2.22 | – | – |
W | 2.6 | 2.3 | 3.1 | 4.25 | 6.5 | 4.8 | 4.8 | 3.5 | 3.8 | 1.5 | 7.19 | 5.63 | 1.25 | 5.50 | – | – |
State of ecosystems by |
CD | CD | CD | TC | vulnerable | TC | TC | CD | CD | CD | vulnerable | TC | CD | TC | – | – |
1.94 | 1.75 | 1.93 | 1.93 | 2.07 | 1.94 | 1.72 | 1.93 | 2.06 | 1.98 | 2.02 | 1.96 | 1.46 | 1.81 | – | – | |
Characteristic by |
bad | STF | bad | bad | STF | bad | STF | bad | STF | STF | STF | bad | bad | bad | – | – |
Inv | 2.29 | 1.98 | 3.15 | 3.28 | 6.86 | 3.88 | 4.23 | 2.81 | 3.40 | 1.75 | 6.13 | 4.90 | 5.00 | 5.00 | – | – |
Characteristic by Inv | bad | bad | STF | STF | good | STF | STF | good | STF | bad | good | STF | STF | STF | ||
Distance to the road, m | 10.0 | 0.5 | 393.0 | 1.0 | 50.0 | 0.2 | 0.2 | 0.2 | 330.0 | 0.2 | 0.2 | 540.0 | 150.0 | 238.0 | 0.2 | 0.2 |
Number of lanes in one direction ( |
4 | 2 | 4 | 1 | 3 | 3 | 4 | 3 | 3 | 2 | 3 | 3 | 3 | 3 | 3 | 3.5 |
Number of cars per hour | 7161.0 | 2010.0 | 4605.0 | 859.5 | 6058.5 | 6058.5 | 7122.0 | 2356.5 | 1956.0 | 2314.5 | 4989.0 | 5085.0 | 3243.0 | 6058.5 | 3312.0 | 4315.0 |
Transport speed, km/h ( |
51.43 | 39.89 | 63.01 | 34.62 | 72.40 | 73.50 | 61.71 | 42.92 | 37.89 | 39.89 | 49.50 | 62.61 | 36.00 | 73.50 | 36.29 | 54.88 |
0.2155 | 0.0861 | 0.0966 | 0.0513 | 0.2109 | 0.2109 | 0.1343 | 0.1161 | 0.1042 | 0.0970 | 0.1763 | 0.1137 | 0.2074 | 0.2109 | 0.1130 | 0.1330 |
Notes: PE numbers as in Fig. 1. Characteristics for
According to Rybakova and Glazunov (2020), on one of the largest highways in the European part of Russia, the load is about 9000 cars per hour (Moscow Ring Road, Moscow). In the centre of Kyiv, the load was 21.1% less than on the Moscow Ring Road. Number of lanes in one direction was one to four. The average speed of cars was 51.9 km/h and the speed range was 34.6–73.5 km/h. Frequent traffic jams in the city centre (Mariinsky, named after Pushkin parks), near the Holosiivskyi NNP, the NBG named after Grishko and Lysa Hora cause a decrease in the average speed of traffic, especially at traffic lights, which increases the number of emissions. For example, near heavily loaded highways, the numbers of points 2, 19c, the average traffic speed was 36.3–39.9 km/h.
HI of vehicle emissions was good only in Pusha-Vodytsya park, satisfactory in seven observation points (43.8% of all points), bad in three points (18.8%) and very bad in five points – range of value of HI 4.787–5.490 (31.3% of PEs; these are named after Pushkin, DSHK park, NBG named after Grishko, Lysa Hora tract and Holosiivskyi NNP), which corresponds to the total concentration of air pollutants of 0.207–0.216 mg/m3. Exceedance of MAC concentrations of NOx, CnHm and lead compounds for humans was determined (Tab 3). HQ
Average daily content of air pollutants in the Kyiv park ecosystems
Contents [mg/m3/No. PE] | 5 | 10 | 2 | 3 | 12 | 14 | 16 | 19c | 9 | 20c | 15 | 1 | 6 | 7 | 17 | 18 | Average | HQ |
Share from MACa.d. |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
NOx | 0.0210 | 0.0475 | 0.0367 | 0.0378 | 0.0413 | 0.0420 | 0.0466 | 0.0468 | 0.0588 | 0.0550 | 0.0687 | 0.0901 | 0.08657 | 0.0866 | 0.0900 | 0.0866 | 0.0589 | 1.47 | 1.47 |
Load characteristics by NOx | good | STF | good | good | STF | STF | STF | STF | STF | STF | bad | very bad | very bad | very bad | very bad | very bad | – | – | – |
CnHm | 0.0283 | 0.0644 | 0.0469 | 0.0555 | 0.0591 | 0.0523 | 0.0621 | 0.0617 | 0.0699 | 0.0739 | 0.1017 | 0.1189 | 0.11454 | 0.1145 | 0.1066 | 0.1145 | 0.0778 | 0.08 | 1.560 |
Soot (CnH) | 0.0002 | 0.0003 | 0.0001 | 0.0002 | 0.0003 | 0.0001 | 0.0005 | 0.0004 | 0.0005 | 0.0002 | 0.0004 | 0.0003 | 0.00110 | 0.0011 | 0.0012 | 0.0011 | 0.0005 | 0.01 | 0.010 |
SO2 | 0.0014 | 0.0030 | 0.0018 | 0.0024 | 0.0028 | 0.0020 | 0.0036 | 0.0032 | 0.0040 | 0.0030 | 0.0043 | 0.0047 | 0.00705 | 0.0071 | 0.0077 | 0.0071 | 0.0041 | 0.08 | 0.081 |
Formaldehyde | 0.0002 | 0.0004 | 0.0002 | 0.0003 | 0.0004 | 0.0002 | 0.0005 | 0.0005 | 0.0006 | 0.0004 | 0.0006 | 0.0006 | 0.00103 | 0.0010 | 0.0013 | 0.0010 | 0.0006 | 0.20 | 0.192 |
Lead compounds | 0.0002 | 0.0004 | 0.0004 | 0.0003 | 0.0003 | 0.0004 | 0.0003 | 0.0004 | 0.0005 | 0.0005 | 0.0006 | 0.0008 | 0.00060 | 0.0006 | 0.0006 | 0.0006 | 0.0005 | 1.58 | 1.560 |
Sum | 0.0513 | 0.1161 | 0.0861 | 0.0966 | 0.1042 | 0.0970 | 0.1137 | 0.1130 | 0.1343 | 0.1330 | 0.1763 | 0.2155 | 0.21090 | 0.2109 | 0.2074 | 0.2109 | 0.1423 | – | – |
HI | 1.243 | 2.838 | 2.261 | 2.247 | 2.422 | 2.591 | 2.620 | 2.732 | 3.446 | 3.347 | 4.072 | 5.490 | 4.787 | 4.787 | 5.010 | 4.787 | – | – | – |
Characteristic by HI | good | STF | STF | STF | STF | STF | STF | STF | bad | bad | bad | very bad | very bad | very bad | very bad | very bad | – | – | – |
Notes: denotement as in Fig. 1. PEs are arranged in order of increasing HI. STF denotes satisfactory condition; characteristics of air load (NOx, HI) are according to Table 1. Exceeding MACa.d. for humans and high load characteristics by NOx was in bold.
The phytotoxicant NOx had the largest share of vehicle emissions, which was 1.5 MACa.d. near PEs 1, 6, 7, 17 and 18. Since MACa.d. is two times lower for green plantations, the concentration of this pollutant in the air is 2.9 MACa.d. for plants (Tab. 4). Such concentrations of air pollutants pose a direct threat to green infrastructure. The highest concentrations of hydrocarbons (CnHm) nears PE 1, 6, 17 and 18 were 1.56 MACa.d. for humans and 0.56 MACa.d. for plants. The highest concentrations were near the following observation points: for soot (CnH) – at points 9, 15, 16, 19c; for SO2 – points 6, 7, 17 and 18; for formaldehyde –at points 1, 15, 16 and 19c; and for lead compounds – near points 1, 6, 7, 15, 17 and 18. The lowest amount of NOx emissions was near PEs 2, 3, 5, 12, 14, 16 and 19c, although at some of these points, this concentration still exceeded the MACa.d. for humans and plants. The lowest amount of emissions of lead compounds was near the points 5, 12 and 16 – 0.0002–0.0003 mg/m3, which is equal to the MACa.d. for humans. Presence of constant concentrations of air pollutants at the level of MACa.d. is also harmful. MACa.d. for plants differs according to different authors: for vegetation of parks (Polyakova, Gutnikov, 2000): NOx – 0.03 mg/m3, SO2 – 0.04 mg/m3 (Tab. 4).
Assessment of air quality in Kyiv
Air pollutants | Actual average annual concentrations for 20191 [mg/m3] | The average daily concentration, our calculations [mg/m3] | MACa.d. [mg/m3] for humans2 | MACa.d.3 for plants |
---|---|---|---|---|
NOx converted to NO2 | 0.14400 | 0.0570 | 0.0400 | 0.020 |
SO2 | 0.07500 | 0.0039 | 0.0500 | 0.015 |
Formaldehyde | 0.00560 | 0.0006 | 0.0030 | 0.003 |
Saturated hydrocarbons (CnHm) | – | 0.0754 | 0.0500 | 0.140 |
Soot (CnH) | 0.03500 | 0.0005 | 0.0500 | 0.050 |
Inorganic lead compounds | 0.00003 | 0.0005 | 0.0003 | – |
Notes:
according to Furdychko et al. (2008).
According to our data, exceeding the MAC a.d. for humans and plants for formaldehyde, hydrocarbons, NOx has been obtained. Average annual concentrations of NOx (3.5 MACa.d.), SO2 (1.5 MACa.d.) and formal-dehyde (1.9 MACa.d.) exceeded the MACa.d. for humans and plants (Tab. 4).
With HQ ≤ 1, there is no risk of adverse effects on human health. With an increase in HQ
Correlations between air pollution and the state of PE are presented in Table 5.
Correlation of the investigated PE parameters
Number of cars per hour | HI | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | ||||||||||||
−0.46 | 1 | |||||||||||
0.09 | 0.13 | 1 | ||||||||||
−0.37 | 0.46 | 0.41 | 1 | |||||||||
0.52 | −0.33 | −0.01 | −0.62 | 1 | ||||||||
0.54 | 0.27 | 0.18 | 0.05 | 0.25 | 1 | |||||||
0.46 | 0.13 | 0.40 | 0.31 | 0.21 | 0.48 | 1 | ||||||
0.38 | 0.12 | 0.03 | −0.30 | 0.42 | 0.75 | 0.03 | 1 | |||||
0.26 | −0.21 | −0.46 | −0.21 | 0.24 | 0.12 | −0.06 | 0.20 | 1 | ||||
Number of cars per hour | 0.59 | −0.21 | −0.19 | −0.36 | 0.27 | 0.45 | 0.02 | 0.44 | 0.75 | 1 | ||
0.34 | 0.00 | −0.24 | −0.58 | 0.23 | 0.26 | −0.16 | 0.54 | 0.49 | 0.72 | 1 | ||
0.29 | −0.04 | −0.26 | −0.57 | 0.19 | 0.16 | –0.21 | 0.45 | 0.51 | 0.72 | 0.99 | 1 |
Note: medium and strong correlations are highlighted.
As the number of cars increases,
HI was carried out based on the determination of the number of vehicles, the amount of emissions of air pollutants, the intraterritorial zoning of the urban ecosystem, (Fig. 3–5). Zones were selected as in Table 1.
Zones by the concentrations sum of aerial emissions and HI (Fig. 3, 4) are concentric and coincide – the largest air pollution was at the points of NBG named after Grishko, Lysa Hora, Holosiivskyi NNP; and in the city centre Pushkin, Nyvky parks. The least air pollution from cars was near Pushcha-Vodytsya (PE 5, although the condition of plantations here is greatly weakened and the mortality of trees is significant [35%]) because here, most of the plantations consisted of
Mapping GIS by the number of cars per hour is slightly different from mapping the concentrations of air pollutants. The worst areas were near the parks Nyvky, Syretsky, Mariinsky, named after Pushkin, NBG named after Grishko, Holosiivskyi NNP and Lysa Hora (Fig. 5). This can be explained by the peculiarity of the roads’ locations, their smaller width and capacity, the features of the old city centre, more congestion and reduced speed of cars in traffic jams, when the engine is idling, where the number of cars is less. The concentration of air pollutants depends on shares of prevailing wind directions West, South, too.
Verification of the division of the HQ and HI indices obtained for PE into groups depending on the level of air pollution was performed by cluster analysis using Euclidean distance, and Ward's method was used to combine the clusters (Fig. 6).
It was found that based on the NOx concentration, the measurement points of PEs can be divided into two groups – the largest pollution was found in the PEs NBG named after Grishko, Lysa Hora tract, Holosiivskyi NNP and DSHK park (Fig. 6A). According to the SO2 concentration, the measurement points are divided into two groups – the largest air pollution was near four PEs (NBG named after Grishko, Lysa Hora, Holosiivskyi NNP and DSHK park; Fig. 6B). The maximum values of HI are found near five PEs – park named after Pushkin, NBG named after Grishko, Lysa Hora tract, Holosiivskyi NNP and DSHK park (Fig. 7).
The largest number of cars was found in the city centre near the Park of Eternal Glory, NBG named after Grishko, Lysa Hora and Holosiivskyi NNP. On the left bank, air pollution was less and the highest concentration of pollutants was near the DSHK park. The intensity of traffic here was 3.2 thousand cars per hour; there were frequent traffic jams (the average speed of traffic was 36 km/h) (Fig. 7).
HI of vehicle emissions and the concentration of air pollutants (component F1) generated 32% of the variability of PE state integrated indices. Also, 28% of the variability of signs was formed by the F2 component (
We studied the impact of vehicle emissions on the generative sphere of plants – the proportion of sterile and teratomorphic pollen grains of
Sterility of
No PE | Distance to the road [m] | Number of cars per hour | Pollen grains (pieces) |
Number of sterile pollen (pieces) |
Share of a sterile pollen ( |
CID | ||
---|---|---|---|---|---|---|---|---|
5 | 238 | 860.0 | 1785 ± 8.86 | 34 | 236 ± 2.74 | 21 | 13.00 | 0.21 |
2 | 226 | 2010.0 | 1715 ± 9.26 | 33 | 342 ± 2.57 | 20 | 19.92 | 0.58 |
10 | 80 | 2357.0 | 1589 ± 6.68 | 28 | 344 ± 2.71 | 19 | 22.00 | 0.73 |
15 | 5 | 4989.0 | 1396 ± 11.26 | 44 | 361 ± 3.21 | 25 | 25.86 | 0.91 |
16 | 1000 | 5085.0 | 2035 ± 7.75 | 34 | 235 ± 4.53 | 27 | 11.55 | 0.17 |
7 | 143 | 6059.0 | 1506 ± 9.77 | 43 | 361 ± 3.27 | 24 | 23.97 | 0.86 |
Notes: CID – conditional indicator of damage, PE – park ecosystem,
Mean values differ significantly in the Student's
In addition to the typical pollen grains of
It was found that the lowest level of
With increasing concentration of air pollutants, the number of teratomorphic pollen grains increases. As in PE 2, sampling was performed at a distance of about 226 m from the roads, so the HI index was 2.26 (satisfactory).
In PE 7, 10 and 15, there was a significant excess of the studied indicators, which shows an additional negative impact of aerotechnogenic factors. PE 7 (Lysa Hora) and PE 15 (Babyn Yar) showed ‘extremely dangerous’ characteristics of the urban environment, which is confirmed by the highest amount of sterile pollen
Correlation of air pollution and pollen indication
Distance to the road [m] | Number of cars per hour | CID | Inv | HI | |||||
---|---|---|---|---|---|---|---|---|---|
Distance to the road [m] | 1.00 | ||||||||
Number of cars per hour | 0.21 | 1.00 | |||||||
0.57 | 0.80 | 1.00 | |||||||
−0.78 | 0.36 | −0.14 | 1.00 | ||||||
−0.78 | 0.40 | −0.11 | 0.99 | 1.00 | |||||
CID | −0.75 | 0.41 | −0.11 | 1.00 | 1.00 | 1.00 | |||
Inv | 0.17 | 0.68 | 0.84 | 0.15 | 0.16 | 0.16 | 1.00 | ||
−0.25 | 0.89 | 0.48 | 0.72 | 0.76 | 0.76 | 0.53 | 1.00 | ||
HI | −0.29 | 0.86 | 0.44 | 0.76 | 0.80 | 0.80 | 0.49 | 1.00 | 1.00 |
Note. A strong correlation is highlighted. CID – conditional indicator of damage, HI – hazard index.
With increasing distance to roads and the number of cars, the coefficient of variation in the amount of sterile pollen increases (
Climate change within the metropolis compared to its surroundings, terrain, loss of green areas in recent decades, the spread of areas covered with asphalt and concrete, significant construction and loss of heating networks increase the temperature of ground layers, reduce relative humidity and change the wind regime. High density of highways causes intense gassiness and air pollution (Shevchenko and Snizhko 2008; Van Wittenberghe et al. 2012; Wei et al. 2021). Stagnant phenomena contribute to the intensive accumulation of impurities in the city. High air temperature and solar radiation contribute to the photochemical reactions of formaldehyde formation, and stagnant air leads to an increase in its concentration. Thus, within the city, there is a significant differentiation of meteorological indicators. In urban conditions, the wind speed decreases significantly, which is associated with an increase in the roughness of the underlying surface. There is also a relative increase in wind speed on some streets and massifs (Shevchenko and Snizhko 2008; Vieira et al. 2018; Arghavani et al. 2021). These indicators in the complex have different effects on the dispersion of harmful impurities from vehicles and their deposition on the edge of the forest and within the green infrastructure and spread over large areas. Our research has shown that although the prevailing winds in the metropolis are in north, west and south directions, the spread of air pollutants occurs in the direction of east – in the valley of the Dnipro. Therefore, the process of air pollution should be considered as probable and the concentration of impurities at each point as random functions of coordinates and time (Kiptenko and Kozlenko 2016; Bonilla-Bedoya et al. 2021). In our research, the highest level of pollution was associated with the terrain and building features of the city, the specific conditions of location and capacity of roads, and aggregated green infrastructure. Greenery is important for urban systems because it absorbs air and dust pollutants (Pietras-Couffignal and Robakowski 2019; Jaung et al. 2020; Jin et al. 2021); additionally, it cools and humidifies the air, regulates the microclimate and mitigates the urban heat island effect (Vieira et al. 2018; Jaung et al. 2020; Wei et al. 2021). In summer, greenery helps to reduce the air temperature by 4°C−6°C and increase the humidity by 10%−15%. The presence of trees reduces the air temperature in summer (1.1°C), significantly cools the surface (12°C) and reduces wind speed by 45% (Georgi and Tzesouri 2008). Single- and double-row greenery, 5–10 m wide, reduces air pollution by 5%–25%. A strip of tree–shrub plantations 10–14 m wide reduces the concentration of carbon dioxide by 40%–45% and the sound level by 2–8 dB (Polyakova and Gutnikov 2000; Jaung et al. 2020). PE reduces the level of air pollution by 40%–70%, depending on the plant height and completeness. The larger the area of green infrastructure, the better the air quality in urban areas (Van Wittenberghe et al. 2012; Jaung et al. 2020; Bonilla-Bedoya et al. 2021) and the lesser the manifestations of near-surface turbulence or air stagnation (Arghavani et al. 2021).
The zone of negative impact of vehicles on the greenery of cities is 20–60 m and in some cases, up to 100 m in the depth of plantings. This is due to a complex of natural and anthropic factors: vegetation stability, the influence of microclimatic features, geochemical soil conditions, landscape characteristics and planning structure of the territory (Polyakova and Gutnikov 2000; Pietras-Couffignal and Robakowski 2019). In the roadside, about 20% of the particles (size ≥0.005 mm) settle near the road, about 60% (≤0.001 mm) settle in the area of 10–100 m and the rest are carried by the wind over long distances (Jin et al. 2021). Dispersion of pollutant emissions is influenced by the azimuth of the route and the prevailing wind direction. On the leeward side of the road, the accumulation of heavy metals in the soil increases by 2 times (Pietras-Couffignal and Robakowski 2019; Polyakova and Gutnikov 2000; Bonilla-Bedoya et al. 2021). It is proved that the intensity of traffic has a negative impact on growth in height, diameter of trees and their living condition (Miroshnyk 2018; Pietras-Couffignal and Robakowski 2019). The intensity of traffic flow over 300 cars per hour and the distance less than 100 m from the carriageway of streets are considered to be dangerous for biota and humans (Klebanova and Klebanov 2011). According to our data, the average traffic intensity on the highways of Kyiv is 4219 cars per hour and exceeds the optimal by 92.9%. Interestingly, in 2010, the load of roads near PE 6 (NBG named after Grishko) was 3.2 thousand cars per hour (Rud, 2013), that is, 2 times less than now. The average traffic intensity in the city in 2018 was 4.1 thousand cars per hour (Rabosh and Kofanova 2019), and according to our data in 2020, it was 4.2 thousand cars per hour.
Under the influence of aerotechnogenic pollution, there is a deterioration of trees, their drying, defoliation of crowns and deterioration of integrated indicators of ecosystems (Bednova et al. 2015; Miroshnyk 2018; Lavrov et al. 2019; Pietras-Couffignal and Robakowski 2019; Vacek et al. 2020). We also observed similar processes. We studied the correlations between the parameters of pollen indication in Kyiv (Mazura et al. 2020), but now, it is found that compared to studies in 2013 (Kudryavska and Dychko 2013), there has been a deterioration of the environmental situation in the integrated indicator of CID by 19.3% for 7 years. We have shown that there is a process of nitrification in PEs with excess nitrogen from the emissions of vehicles through phytoindication (Miroshnyk 2020). Indicators of crown defoliation, the share of premature yellowing of leaves and dechromation of leaves of
We found that in the conditions of the urban ecosystem of Kyiv, the vital state of 14 PEs and the state of the generative sphere of
Pollutants significantly affect plant pollen, accompanied by changes in the morphological parameters of pollen grains, increasing the abnormal pollen fraction and reducing fertility and viability (Cuinica et al. 2014, 2015; Azzazy 2016; Mazura et al. 2020; Leghari et al. 2018). Cuinica et al. (2015) indicated that even at low levels of pollutants below the standard level of safety for human health, pollen viability decreased to 25%. The total amount of teratomorphic pollen increased with increasing concentration of air pollutants and reached 11.1% (Ivanchenko and Bessonova 2016; Petrushkevych and Korshykov 2020). The percentage of natural polymorphism of pollen grains in plants under favourable conditions usually does not exceed 5%–10% and rarely exceeds 20% (Dzyuba 2006; Ivanchenko and Bessonova 2016). In our studies, the amount of teratomorphic pollen reached 41.4% and increased with increasing concentration of contaminants (
PE is divided into two groups according to the level of air pollution. Green infrastructure is highly responsive to air pollution, as it has been experimentally proven that the concentration of air pollutants for plants, which leads to damage, is less than for humans (Nikolaevsky 1998; Polyakova and Gutnikov 2000; Furdychko et al. 2008; Cuinica et al. 2015). Our bioindication results show that the state of PEs depends on the amount of vehicle emissions, but not all indicators have a linear relationship, which requires further research. Under the influence of pollutants on the same organs or systems of the body, the most likely type of their combined effect is summation or additivity. Although this approach may exaggerate the health hazards, it has a greater advantage than a separate assessment of each component. In the case of a combined presence in atmospheric air, the effects of summation of biological action for NO2, NO, SO2 and fuel oil ash; NO2, formaldehyde; and SO2 and NO2 were established (Environmental Protection 2005; Order of the Ukraine Ministry 2020). Therefore, the total emission concentrations from vehicles and the HI are indicators that describe the impact on urban ecosystems. It is important to create a system of informative indicators for assessing the state of the environment and for the long-term monitoring of urban systems (Cuinica et al. 2015; Azzazy 2016; Vacek et al. 2020). We have developed the rationing and parameters of indication values of biotic indices and abiotic characteristics of the urban system of Kyiv. Value of NOx concentration in the air <0.020 mg/m3 is very good and >0.081 is very bad; value of HI <1.060 is very good and >4.242 is very bad.
The analysis indicates the complex nature of air pollution in Kyiv from vehicles and its distribution, taking into account the influence of prevailing winds and the terrain of the city, and the reaction of PEs to it. The results of our study emphasise the importance of green infrastructure for improving air quality in megacities. There is a need to plan the expansion of green areas to improve the quality of ecosystem services, urban microclimate, air, human life and health.
For the first time, for the urban ecosystem of Kyiv, zoning and analysis of the spread of aerial emissions from vehicles using GIS technologies was conducted. The state of green infrastructure was integrated and its dependence on the level of air emissions from vehicles was proved. Our research indicates the dependence of the response of living systems to air pollution at the level of the cell, organism, group and PEs in time and space. Therefore, it is recommended to use integrated indicators of the state of PEs as a response of ecosystems to aerotechnogenic pollution.
In our research, the primary information about the state of green plantations was systematised into the following blocks: the state of the stand, grass tier and the structural diversity of PE. As parameters of the abiotic environment, the levels of air pollution from vehicles were recorded. The ranges of values of ecological indicators of the state of PEs in the conditions of the metropolis were developed, tested and defined. It was found that a high and above-average level of damage to the generative sphere of plants is characteristic of the areas with the highest level of pollution. Green infrastructure needs to be expanded to improve the urban environment and reduce pollution. For this purpose, it is necessary to optimise the transport infrastructure (expand transport interchanges to reduce congestion, build bypass roads or highways to increase the speed of vehicles, which will reduce the emission of air pollutants when braking at traffic lights and in traffic jams), plant protective plantings of four to six rows along highways, design new microdistricts taking into account the microclimate, terrain and prevailing winds to increase aeration, and improve the air quality for humans to breathe clean air.