Although there are no studies that directly evaluate this hypothesis, some indirect results support it 10,11: high concentrations of O3, CO2, NOx, small carbon particles (PM <10) can cause hyperactivity in the respiratory tract inducing asthma or rhinitis, but also can alter the proteins of food and pollen grains 12,13, generating allergenic proteins with greater capacity to induce the production of IgE and the activation of T lymphocytes. This evidence concerns the gene IGHE and rhinitis.