The Nevada County Public Health Department, in conjunction with a release by the Air Quality District, has issued an air quality advisory for sensitive groups. The air quality in combination with the heat can make the outdoors a problem for those people who are in a sensitive group. Sensitive groups (those most at risk from exposure to ground level ozone) are typically comprised of individuals who may be elderly, children, asthmatics, adults with pre-existing heart and lung disease, pregnant women and people who are exercising outdoors. Exposure to unhealthful ozone concentrations can result in eye and throat irritation, headaches, nausea, shortness of breath, congestion, coughing, impaired lung function and chest pain. Sensitive individuals are advised to avoid prolonged or heavy outdoor exertion, especially during the late afternoon and evening Thursday.