The present invention provides methods and compositions for the stimulation of immune responses. Specifically, the present invention provides methods and compositions for the use of nanoemulsion compounds as mucosal adjuvants to induce immunity against environmental pathogens. Accordingly, in some embodiments, the present invention provides nanoemulsion vaccines comprising a nanoemulsion and an inactivated pathogen or protein derived from the pathogen. The present invention thus provides improved vaccines against a variety of environmental and human-released pathogens.