The Met Office offers a daily pollen guide, in tones not unlike the storm warning of the shipping forecast: poetic for those not affected, alarming if you are facing a force 8. Saturday’s reads: “The grass pollen risk is on the rise, as more grasses come into flower. Nettle, dock and plantain pollen also airborne. Fungal spores: Cladosporium at increasing risk.” As someone who grew up sneezing and wheezing through the early summer (and who remembers the Russian roulette of fruitcake-eating with a nut allergy in the years before EpiPens), I have mixed feelings about that information. I don’t want to jinx it, but I seem (finally) to have grown out of hay fever. At least to the extent that I could sit in the garden on Saturday and read Theresa MacPhail’s fascinating new book, Allergic: How Our Immune System Reacts to a Changing World, without rubbing itchy eyes. If I have overcome my allergies, I’m very much in a minority. MacPhail, an American medical anthropologist, offers all sorts of alarming statistics about the global rise of allergic reactions – 44% of UK adults have an allergy of some kind – and goes in indefatigable search of the reasons for them. The epidemic seems to be a complex result of many modern lifestyle changes at a cellular level: one factor is the “hygiene hypothesis”, in which infants in more urban environments are exposed to fewer potential allergens (and far more antibiotics and antimicrobial cleaning) than ever before. There are the dramatic changes, too, in the adult diet (far more sugar) and skincare (far more products); and also the presence in our surroundings – and our bodies – of many more plastics and pollutants. “Allergic disease,” MacPhail tentatively concludes, “is a barrier problem not necessarily an immune problem.” We are making our skin and our gut more vulnerable to a changing environment. After reading the book, I listened to an interview with the author – also a hay fever sufferer – in which she noted the habits she had changed after writing her book: she eats far more fibre from fruit and veg; she doesn’t change her sheets so often; and she doesn’t shower every day… New balls A strange thing happened in the French Open tennis semi-final between Novak Djokovic and Carlos Alcaraz on Friday. The match had been billed as a generational battle: Alcaraz is 20, Djokovic is 36. The intensity of the play and the gruelling heat in Paris might, you imagine, have favoured the younger man, but it was Alcaraz who cramped up after two sets and Djokovic who prevailed. His victory was another reminder that elite tennis has become an older player’s game. Before Sunday’s final there has, incredibly, been no male winner of this tournament, or of Wimbledon, born after 1987. The trend is reflected in other sports, but it has, I fear, come slightly too late for fiftysomething parks players to perfect their second serve. Bible bashing You had to smile at the anonymous parents in Mormon Utah who responded to the fundamentalist Christian zeal for banning books in schools by demanding the removal from library shelves of the Bible, on the grounds of its pornographic content (“incest, onanism, bestiality, prostitution…”). The real laugh, though, was reserved for the state’s censors, who felt obliged to comply with the demand. It was a real-life lesson in Saul Bellow’s famous argument for literary and other freedoms: “There is no fineness or accuracy in suppression; if you hold down one thing, you hold down the adjoining.” Tim Adams is an Observer columnist