Climate changes may alter pollen counts

Issue: April 2010

Continuing climate changes coupled with high temperatures contributed to longer pollen seasons, increased pollen loads and caused greater numbers of people to develop sensitization to allergenic pollens, according to recent study findings.

Researchers from Genoa University in Italy collected data on pollen counts, duration of pollen seasons and prevalence of sensitization for birch, cypress, olive, grass and Parietaria in the Bordighera region (Western Liguria) from 1981 to 2007. The researchers also recorded average temperature, direct irradiation, humidity, sunny days and rainfall.

Results indicated an escalating increase of pollen season durations along with advancing start dates during the study period for Parietaria, olive and cypress, according to the researchers. Data also suggested a relationship between these upsurges and a rising percentage of patients who were sensitized to those allergens. However, the researchers also noted that rates of sensitization to dust mites remained steady during the study. Additionally, the researchers indicated a potential correlation between continual increases in direct radiation and days with temperatures warmer than 30·C.

“By studying a well-defined geographical region, we observed that the progressive increase of the average temperature has prolonged the duration of the pollen seasons of some plants and, consequently, the overall pollen load,” G. Walter Canonica, MD, past president of the World Allergy Organization, said in a press release.

Estelle Levetin, PhD, member of the National Allergy Bureau of AAAAI, added in the press release that “longer pollen seasons and high levels of pollen certainly can exacerbate symptoms for people with allergic rhinitis and for those who previously had minimal symptoms.” – by Melissa Foster

Ariano R. #754. Presented at: 2010 Annual Meeting of the American Academy of Asthma, Allergy and Immunology; Feb. 26-March 2, 2010; New Orleans.