**6. Climate change and allergies**

Pollen allergy currently affects significant proportion of the population. A warmer climate will lead to a longer pollen season and more days with high pollen counts. In addition, a warmer climate increases the risk of proliferation of new plants with well-known allergenic pollens like ragweed, plane tree and wall pellitory. The consequences will be more people with hay fever and pollen asthma, longer allergy seasons and an increase in the severity of symptoms, disease-related costs and demands on health care for diagnosis and treatment of more complex allergies. It is clearly identified that climate change can exert a range of effects on pollen, which might have consequences for pollen-allergic patients. The pollen season might become longer thereby extending the period in which patients suffer from allergy symptoms. This extension of the pollen season could be due to a prolonged flowering period of certain species, e.g. grasses, or the appearance of new species that flower in late summer, e.g. common ragweed. Climate change could cause an increase in heavy thunderstorms on summer days in the grass pollen season, which are known to increase the chance of asthma exacerbations (sommer et al, 2009).

Climate change alters the concentration and distribution of air pollutants and interferes with the seasonal presence of allergenic pollens in the atmosphere by prolonging these periods. The link between climate change and respiratory allergies is most importantly explained by the worsening ambient air pollution and altered local and regional pollen production. Laboratory studies confirm epidemiologic evidence that air pollution adversely affects lung function in asthmatics. Damage to airway mucous membranes and impaired mucociliary clearance caused by air pollution may facilitate access of inhaled allergens to the cells of the immune system, thus promoting sensitization of the airway. Consequently, a more severe immunoglobulin (Ig) E-mediated response to aeroallergens and airway inflammation could account for increasing prevalence of allergic respiratory diseases in polluted urban areas (D'Amato et al, 2010).

#### **6.1 Molds**

Aeroallergens that may respond to climate change include outdoor pollens generated by trees, grasses, and weeds, and spores released by outdoor or indoor molds. Because climatologic influences differ for these different classes of aeroallergens, they are discussed separately here. As compared with pollens, molds have been much less studied. This may reflect in part the relative paucity of routine mold monitoring data from which trends might be analyzed, as well as the complex relationships among climate factors, mold growth, spore release, and airborne measurements.63 In addition to potential effects on outdoor mold growth and allergen release related to changing climate variables, there is also concern about indoor mold growth in association with rising air moisture and especially after extreme storms, which can cause widespread indoor moisture problems from flooding and leaks in the building envelope. Molds need high levels of surface moisture to become established and flourish (Kinney, 2008).

The urban heat island effect, a combination of anthropogenic and climatologic heat, can increase urban temperatures as much as 5°C compared with rural locations and further drive the formation of ozone.

Climate Change and Health Effects 49

borne illness and food insecurity, both likely outcomes of climate change, may lead to malnutrition. While adult humans exposed to mild famine usually recover quite well when food again becomes plentiful, nutritional reductions to a fetus in the womb appear to have lasting effects throughout life. Climate change effects on food availability and nutritional content could have a marked, multigenerational effect on human development. Certain commercial chemicals present in storage sites or hazardous waste sites can alter human development. Flooding from extreme weather events and sea-level rise are likely to result in the release of some of these chemicals and heavy metals, most likely affecting drinking and recreational waters. Some of these, including mercury and lead, have known negative

Since last 30 years there has been concern that anthropogenic damage to the earth's stratospheric ozone layer will lead to an increase of solar ultraviolet (UV) radiation reaching the earth's surface, with a consequent adverse impact on human health, especially to the skin. More recently, there has been an increased awareness of the interactions between ozone depletion and climate change (global warming), which could also impact on human exposure to terrestrial UV. The most serious effect of changing UV exposure of human skin is the potential rise in incidence of skin cancers. Climate change, which is predicted to lead to an increased frequency of extreme temperature events and high summer temperatures. This could impact on human UV exposure by encouraging people to spend more time in the sun. While future social trends remain uncertain, it is likely that over this century behavior associated with climate change, rather than ozone depletion, will be the largest determinant

Climate change has potential to influence mental health and behavior. It is observed that those with lower socioeconomic standing are more likely to choose to relocate permanently following a devastating event, often due to limited resources to rebuild property and restore livelihood. In addition, people will continue to experience place-based distress caused by the effects of climate change due to involuntary migration or the loss of connection to one's

Climatic changes may have a significant impact on various dimensions of mental health and well-being. India has been witnessing high incidence of for cotton farmers' deaths/suicides since 1998. The socioeconomic-political factors emerge as very strong determinants of deaths, given the occupational work environment. Also there is decreasing yield of cotton over the years resulting in loss of revenue for the farmers leading them to mental distress. (Patil, 2002) Violent crime may be exacerbated during heat waves because more stress hormones are released when people are exposed to excessive heat (simister & Cooper, 2004). More alcohol and drugs may be consumed during heat waves, and more people may seek help for their psychiatric problems during these periods (Bulbena et al, 2006). Drought appears to contribute to a variety of mental health effects, including more stress, grief, and hopelessness as well a sense of solastalgia, which describes a palpable sense of dislocation and loss people feel when they perceive changes to their local environment are pervasively harmful (Sartore et al, 2007).Conflict among people may be one of the hallmarks of climate

of sun exposure, and consequent impact on skin cancer (Diffey, 2004).

home environment, a phenomenon called "Solastalgia". (IWGCCH)

developmental effects (IWGCCH, u.d).

**8. Cancer** 

**9. Mental health** 

Air pollution can interact with pollen grains, leading to an increased release of antigens characterized by modified allergenicity.

Air pollution can interact with allergen-carrying paucimicronic particles derived from plants. The paucimicronic particles, pollen-originated or not, are able to reach peripheral airways with inhaled air, inducing asthma in sensitized subjects.

Air pollution—in particular ozone, PM, and sulfur dioxide—have been shown to have an inflammatory effect on the airways of susceptible subjects, causing increased permeability, easier penetration of pollen allergens in the mucus membranes, and easier interaction with cells of the immune system.

There is also evidence that predisposed subjects have increased airway reactivity induced by air pollution and increased bronchial responsiveness to inhaled pollen allergens.

Some components of air pollution seem to have an adjuvant immunologic effect on IgE synthesis in atopic subjects—in particular, DEPs, which can interact in atmosphere with pollens or paucimicronic particles.

Table 1. The rationale for the interrelationship between agents of air pollution and pollen allergens in inducing respiratory allergy (Shea et al, 2008).
