The lake continued to dry up, exposing more lake bed known as playa, and sending nearby communities clouds of toxic dust. With a dense blend of ozone and particulate matter, Imperial County became known for some of the worst air quality in the country. Eastern Coachella communities have disproportionately higher rates of asthma and respiratory complications because of high concentrations of contaminants in the air. Scientists are studying how much of this is due to the Salton Sea dust and what is actually in the windblown particles. Ten schools in the Imperial Valley use green, yellow, and red flags signaling air quality for the many children who have asthma. Green means they join their friends on the playground, whereas red means they stay inside all day. Parents can also receive emailed alerts from the Imperial County Air Pollution Control District. Local activists ask if this is an issue of environmental justice, since the area most impacted is 85% Latinos. Some 650,000 people live where there are significant exposure to the dust. The public health impacts of continuing not to meet federal air quality standards include the treatment of child and adult asthma, cardiac disease, lung cancer, and increased mortality rates. Lower concentrations of the wind-borne dust travels all they way into Southern California and Arizona. Residents in the Los Angeles Basin, some away, complained about the odor that drifted their way in 2012, after the biomass on the sea bottom was churned by a storm.