Pollen calendar to depict seasonal periodicities of airborne pollen species in a city situated in Indo-Gangetic plain, India
The growing incidences of asthma, allergic rhinitis/hayfever, and other pollen-associated allergenic diseases have become an important issue in recent years. The highest pollen concentrations were observed from February to April, corresponding to the pollen taxa seasonality that mainly contributes to the local airborne pollen spectrum.
Pollen allergies can cause asthma, allergic rhinitis, allergic conjunctivitis, skin rashes and other manifestation of allergy.
common symptoms are sneezing, itching, dark circles under the eyes (allergic shiners), allergic salute(persistent rubbing of the nose to push it up, most common in children, and conjunctivitis.
This is known as Pollinosis
So which plants fairly commonly cause allergies in India?
A lot of flowering plants grow in the tropical climate of India. Some plants which flower throughout the year spread pollen all the year round. They are known as perennial plants. They can cause allergy throughout the year. Most of the grasses, mustard, castor oil, papaya tree , mesquite and weeds like parthenium, amaranthus and chenopodium shed pollen throughout the year.
While plants like mango tree and a few other plants flower in specific seasons
However as per the Aria guidelines allergies are no longer classified into seasonal or perennial. They are known as persistent or intermmitent, mild, moderate or severe depending on the duration.
Common Allergy seasons are January to June, when most flowering plants shed pollen. and post monsoon till Novemberwhen tnere is a spurt in grass and weeds.
Global warming has lead to increased pollen allergy due to increased summer and warm climate favouring flowering of grasses and other trees.
What are weeds? weeds are small plants which are not planted deliberately. Their seeds are carried on the wind. They grow on the side of the road or in vacant lots like below
So a lot of people believe that pollen allergy is a thing of open grasslands and villages, not the cities. Wrong. A lot of wild plants and weeds which grow at the sides of gutters and the road fairly can cause allergy.
Pollen from grass and some trees is very small and is carried by the wind from one plant to the other. Some pollen can travel for hundreds of kilometres , mixing with the dust in the cities .Pollutants like smoke, petrol and diesel fumes in the air can worsen your allergies.
Following plants cause allergy throughout the year:
Plants like Doob grass or bermuda grass, the common Durva grass which is used for the pooja of Lord Ganesha. It is commonly used as a lawn grass. It is a major course of allergy
The airborne pollen calendar of Chandigarh depicts seasonal periodicities. The annual cycle shows two main seasons, i.e., a spring season dominated by arboreal pollen types (Celtis occidentalis, Eucalyptus sp., Morus alba and Pinus sp.) and autumn season dominated by herbs (Amaranthaceae/Chenopodiaceae, Cannabis sativa and Poaceae). The magnitude of start and end dates with season-length for key species were also observed, showing substantial higher pollen concentration and longer seasons length over a period of two years in Chandigarh. This seems to be linked with their extended reproductive cycle and the flowering period, including the impact of inter-year climatic variations. Identifying key allergic species and their pollen-releasing seasons, including the development of the pollen calendar, will be useful to develop strategies to reduce the impact of pollen allergy for susceptible individuals.
Pollen are considered major outdoor airborne allergens responsible for allergic rhinitis, asthma, and atopic dermatitis in humans (Gilmour et al., 2006; Reid and Gamble, 2009; Peden and Reed, 2010; Chandrika et al., 2017; Krishna et al., 2020). About 10–30% of the worldwide population is affected by pollinosis/allergic rhinitis, which resulted in enormous research practices and consequently led to confirmation of aerobiology as an independent domain (Crouzy et al., 2016; Bastl et al., 2018). Numerous studies conducted in aerobiological research have revealed that pollinosis is expected to increase in the future due to climatic variability, urbanization, industrialization, and pollutant emission (D’Amato et al., 2007; D’Amato et al., 2015; Camacho et al., 2020). Therefore, pollen monitoring is crucial in context to anthropogenic changes affecting the airborne pollen physiology and spectrum.
There is an intrinsic link between pollen phenology, seasonal variation and weather patterns (Rojo et al., 2015). While traveling in the lower troposphere, airborne pollen are subjected to physical and biochemical modification (Sénéchal et al., 2015; Ravindra et al., 2021). Pollen distribution greatly depends on meteorological conditions, micro and macro topography of a particular area (Hjelmroos, 1991; Maya-Manzano et al., 2017). Pollinosis is a regionally variable disease affected by different phenological features of airborne pollen (such as peak concentration). However, these features, including the start and end dates of pollen peaks, are majorly driven by environmental factors such as local airborne spectrum, air pollutants, climatic and weather parameters (Bonofiglio et al., 2008; Aguilera et al., 2014; Lo et al., 2019). As hotspots of air pollution are increasing in India, mainly in the Indo-Gangetic region-IGP (Ravindra et al., 2016; Singh et al., 2020a, 2021), it will likely impact the pollen physiology and spectrum in the future (Azzazy, 2016; Ruiz-Valenzuela and Aguilera, 2018). Thus, knowledge of the temporal and spatial distribution of allergenic pollen taxa is of utmost importance in managing pollen-related allergic diseases.
Diverse knowledge of airborne pollen is of great significance due to its phytopathogenic and allergic effects. Very few studies were conducted in the IGP region to depict the seasonality of airborne pollen.
Major allergen species reported from Northern India are Prosopis juliflora, Ricinus communis, Morus, Cedrus, Holoptelea, Alnus, Chenopodium/Amaranthus, Quercus, Pinus, Ricinus communis, grasses, Argemone and Mallotus. Whereas Central India reported Brassica, Cannabis, Parthenium, Cassia, Azadirachta, grasses, Alnus, Betula, Malotus, Trewia nudiflora and Eastern India reported Lantana, Cucurbita maxima, Cassia fistula, Cocos nucifera. From South India, Cassia, Ageratum, Salvadora, Ricinus, Aibizia lebbeck and Artemisia scopada have been reported as significant aeroallergens (Singh, 2000; Singh and Kumar, 2004; Singh and Dahiya, 2008). The intensity of allergy is directly linked to the species and taxa of airborne pollen, which depends on the threshold value of the individual species (Tseng et al., 2020). Therefore, pollen calendars are necessary to establish possible connections and contributions in the field of etiology to avoid allergic diseases such as allergic rhinitis. However, pollen is known to be dispersed and transported to thousands of kilometers (kms) in the atmosphere
Still, local pollen emissions are considered a principal driving factor behind the pollen concentration in a given location (Smith et al., 2008). Thus, pollen calendars are location-specific, with concentrations closely related to locally distributed flora.
About 20–30% of the population suffers from allergic rhinitis/hayfever in India, and approximately 15% develop asthma
As per the Indian State Forest Report 2019 (ISRF), considering the percentage of the geographical area of State/Union Territory (UTs), the UT of Chandigarh has the highest percentage of tree cover, i.e., 22.34%. And as far as the scenario of forest cover change is considered, the city beautiful has reported a remarkable increase in forest cover (2.18%) in 2019 w.r.t to 2017 (ISFR, 2019). However, an increase in green spaces will also lead to a rise in airborne pollen, consequently increasing pollen-related allergic ailments. Therefore, this is the first study investigating the airborne pollen spectrum of a city situated in IGP during the period of 2-years and producing a pollen calendar to illustrate the seasonal dynamics for major pollen types. The goal of the study is to bring seasonal information to the susceptible population, healthcare professionals, policymakers and scientists to be familiar with the current changes in the environment, which can further help them in developing mitigation strategies. As a prototype study, Chandigarh pollen calendar is developed in order to provide up-to-date information and to highlight the variability of key pollen types in different seasons.
HOW TO PROTECT ONESELF FROM POLLEN ALLERGIES
Pollen dispersion is more in early morning and late evening. Avoid going outside during that time.
Avoid morning walks in Pollen season.
Wear a mask or cover your face while outside. Wear full sleeve clothes.
Take a shower on reaching home immediately and put your clothes to wash to remove pollen particles stuck to it.
Wash your hair often Encourage planting of trees which are noninvasive and known to be non-allergic symptomatic medication as prescribed by your doctor.
Allergy testing for pollen
Allergy vaccines or allergen specific immunotherapy. This is a natural, safe and long term treatment for allergies. More details are available on the post
So while you can’t stop pollen for dispersing with strong immunity and a bit of caution can save you from a lot of discomfort and uneasiness.