The air in Santa Clarita will once again be considered unhealthy for those with certain health conditions Sunday, health officials said. Air quality will be considered unhealthy all day Sunday Sept. 2 for Santa Clarita, Central Los Angeles County, West and East San Gabriel Valley, Pomona and Walnut Valleys and East San Fernando, according to the South Coast Air Quality Management District. Tomorrow’s air quality index, or AQI, is project to be at 118 due to increased ozone presence in the area, according to the EPA’s Airnow website. . Ozone can cause various health issues such as coughing breathing difficulty, and lung damage. Exposure to ozone can make the lungs more likely to get an infection, lung diseases, increase the frequency of asthma attacks and increase the risk of early death from heart or lung disease, according to Air Now. Those with sensitive conditions, including heart disease, asthma and other chronic respiratory diseases should not engage in outdoor activities like sports, according to a news release from the Los Angeles County Department of Public Health.