And conditions can vary drastically. This chart shows the air quality variation on a single day. The bottom axis is time of day, starting with "0" or midnight. From midnight-noon, air quality is in the healthy “green” zone. If an air quality prediction is made at this time, for the entire day, it will soon be wrong. By noon, air quality was deteriorating. By 2pm, a time when many children are getting out of school, the air quality had declined to "unhealthy for all." By 4pm, a time when many children are participating in after school sports and more likely to be outdoors, the air quality was bumping into the “very unhealthy” zone. Chart detailing variation in air pollution levels for September 29, 2011. (Credit: San Joaquin Valley Air District)

Chart detailing variation in air pollution levels for September 29, 2011. (Credit: San Joaquin Valley Air District)

So what to do? The easiest recommendation is for asthmatic children to stay indoors. But staying indoors means children are more sedentary. A sedentary lifestyle increases the risk of obesity, an even bigger public health menace than asthma.

Instead, Tim Tyner, co-author of the study, has solid recommendations for asthmatic children and outdoor play. First, children with asthma are usually prescribed two kinds of medication: controller and rescue. Controller medications should be taken daily, to manage their asthma and prevent symptoms from occurring. Rescue medications are used when symptoms occur, to “rescue” someone from an asthma episode.

Of course, parents need to make sure children use their controller medication properly. But in addition, Tyner says, “Children with asthma should always pre-medicate with their rescue inhaler medication prior to participating in any vigorous physical activity.” And it’s not just on bad air quality days. “It really applies to all situations involving strenuous activity, including good air days or indoor activities.”

Still, on the worst air quality days, all children should stay indoors or, if they must be outdoors, limit the duration and intensity of their outdoor activities, Tyner says.

Team California for Healthy Kids, part of the California Department of Education, encourages schools to adopt programs that increase physical activity throughout the school day. The San Joaquin Valley Air Pollution Control District also has resources on their website to help teachers implement classroom physical activity.

But, now we're back to Khokha's report. If no one is alerting the public that air quality is dangerously bad, how does anyone--parents, teachers, coaches--know that recess or soccer practice or just walking home from school could net a child a trip to the emergency room?

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Asthmatic Kids at Risk in the Central Valley