313
11.4.1 Allergenic Potential of Vegetation
In the ecophysiographic description of three pilot study areas (in this case vegetation was also analysed for the southern part of the Włodarzewska estate where
microclimatic conditions were not considered), a total of 97 different plant species
have been described (see Table 11.2 ). Table 11.3 contains the general evidence of
allergenicity in classes of plants in the studied pilot areas.
It is generally recognised that the Urban Heat Island (UHI) phenomenon has a
detrimental impact on the health of populations that live under its infl uence. This
phenomenon can act as an amplifi er to heat wave events, mainly due to a lack of
night-time thermal body regeneration. It can cause thermal stress through heat accumulation during consecutive days. Such conditions affect a certain population of
city dwellers known to be at risk of developing heat-related illnesses. This population
comprises subjects with chronic pulmonary and cardio- or cerebrovascular disorders, elderly people, young children and the disabled (Basu 2009 ). It is indisputable
that phenomenon such as UHI need to be counteracted by launching various mitigation and adaptation strategies. One must remember that some of those strategies
involve introduction of a new plant species into an urban area. It can mitigate the
UHI phenomenon quite effi ciently, but simultaneously can give rise to another
major health problem. Improper plant choice may cause people who are susceptible
to seasonal airborne allergens to develop symptoms of asthma, rhino conjunctivitis
or urticaria/dermatitis. It is essential for mitigation and adaptation strategies to
select appropriate plant species that do not aggravate the symptoms of airborne
allergies. Although the defi nite impact of the UHI phenomenon on the allergenic
activity of plants has never been described or proven before, there is some evidence
supporting the hypothesis that such phenomena can alter plant physiology, causing
them to be more allergy-aggressive. It has been proved in many studies, that in
warmer climate plants can produce larger amounts of pollens when compared to
those in cooler regions. An increase in carbon dioxide level has a similar impact
(Cecchi et al. 2010 ). Factors typical for urbanized UHI areas such as: elevated ambient temperature, elevated carbon dioxide levels, increase in concentration of
anthropic pollutants, i.e. sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone
and airborne particulate matter (PM) affect plant physiology causing an increase in
allergen production. Pollen grains released in such an environment contain more
allergen proteins on their external surfaces than they do in cooler settings (Todea
et al. 2013 ; Beck et al. 2013 ). Typical pollen grain diameters range from 15 to 40
μm. Such a diameter allows pollen grains to reach only the upper region of the respiratory tract to trigger rhinoconjunctival symptoms. Only particles smaller than 10
μm can penetrate the respiratory tract down to its deeper structures to provoke
asthma seizures. Pollen grains are extremely resistant to fragmentation, however,
allergens can easily be transferred from pollen onto smaller particles (PM 10 , PM 2.5 )
and, in this way, easily reach every compartment of the respiratory tract. Therefore,
increased plant allergenic activity and air pollutants can act synergistically and thus
dramatically reduce the quality of life of subjects susceptible to airborne allergens.
11 Urban Heat Island and Bioclimatic Comfort in Warsaw
11.4.1 Allergenic Potential of Vegetation
In the ecophysiographic description of three pilot study areas (in this case vegetation was also analysed for the southern part of the Włodarzewska estate where
microclimatic conditions were not considered), a total of 97 different plant species
have been described (see Table 11.2 ). Table 11.3 contains the general evidence of
allergenicity in classes of plants in the studied pilot areas.
It is generally recognised that the Urban Heat Island (UHI) phenomenon has a
detrimental impact on the health of populations that live under its infl uence. This
phenomenon can act as an amplifi er to heat wave events, mainly due to a lack of
night-time thermal body regeneration. It can cause thermal stress through heat accumulation during consecutive days. Such conditions affect a certain population of
city dwellers known to be at risk of developing heat-related illnesses. This population
comprises subjects with chronic pulmonary and cardio- or cerebrovascular disorders, elderly people, young children and the disabled (Basu 2009 ). It is indisputable
that phenomenon such as UHI need to be counteracted by launching various mitigation and adaptation strategies. One must remember that some of those strategies
involve introduction of a new plant species into an urban area. It can mitigate the
UHI phenomenon quite effi ciently, but simultaneously can give rise to another
major health problem. Improper plant choice may cause people who are susceptible
to seasonal airborne allergens to develop symptoms of asthma, rhino conjunctivitis
or urticaria/dermatitis. It is essential for mitigation and adaptation strategies to
select appropriate plant species that do not aggravate the symptoms of airborne
allergies. Although the defi nite impact of the UHI phenomenon on the allergenic
activity of plants has never been described or proven before, there is some evidence
supporting the hypothesis that such phenomena can alter plant physiology, causing
them to be more allergy-aggressive. It has been proved in many studies, that in
warmer climate plants can produce larger amounts of pollens when compared to
those in cooler regions. An increase in carbon dioxide level has a similar impact
(Cecchi et al. 2010 ). Factors typical for urbanized UHI areas such as: elevated ambient temperature, elevated carbon dioxide levels, increase in concentration of
anthropic pollutants, i.e. sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone
and airborne particulate matter (PM) affect plant physiology causing an increase in
allergen production. Pollen grains released in such an environment contain more
allergen proteins on their external surfaces than they do in cooler settings (Todea
et al. 2013 ; Beck et al. 2013 ). Typical pollen grain diameters range from 15 to 40
μm. Such a diameter allows pollen grains to reach only the upper region of the respiratory tract to trigger rhinoconjunctival symptoms. Only particles smaller than 10
μm can penetrate the respiratory tract down to its deeper structures to provoke
asthma seizures. Pollen grains are extremely resistant to fragmentation, however,
allergens can easily be transferred from pollen onto smaller particles (PM 10 , PM 2.5 )
and, in this way, easily reach every compartment of the respiratory tract. Therefore,
increased plant allergenic activity and air pollutants can act synergistically and thus
dramatically reduce the quality of life of subjects susceptible to airborne allergens.
11 Urban Heat Island and Bioclimatic Comfort in Warsaw