It’s just the beginning of hot weather across many northern states, but time to recall what rising temperatures do to air quality. Heat worsens air pollution, which harms health in ways that are measurable and pose concerns for society’s most vulnerable, especially children.

Warmer temperatures lead to higher concentrations of ground-level ozone, or smog. A warming climate will worsen this situation. It’s projected to increase emissions of the chemicals that form ozone smog, and speed up ozone-forming chemical reactions in the air, worsening health symptoms. A growing body of scientific research tells us that climate change will lead to higher concentrations of ground-level ozone in many areas of the country. Rising temperatures from human-induced carbon pollution increase ozone smog more in areas with already-high ozone concentrations, meaning that climate change tends to worsen ozone pollution most in already-polluted areas.

Prominent researchers are publishing more and more studies on the links between climate change, air pollution, and harm to kid’s health. The American Academy of Pediatrics issued a policy statement in 2008 that children are especially vulnerable to climate change’s effects, including increased air pollution.

Breathing ozone inflames the deep lung, and people living in ozone-polluted areas are also at increased risk of asthma-related hospital visits and premature mortality. Ozone’s harm to the lung and airways is greater for people who spend time outdoors at work or play – like many kids – because that results in a higher dose to the lung. Asthmatics are especially vulnerable to ozone’s harm; and unfortunately, there are an estimated 7 million US children with asthma. Asthma attacks can be brought on by a number of factors, including exposure to outdoor smog and diesel exhaust, to name two major health-harming air pollutants.

And national asthma rates are rising again, in all age categories but especially among children, according to the Centers for Disease Control and Prevention (CDC). 25 million Americans now have asthma. The greatest increase between 2001 and 2009 was in African-American children – almost 50%. In 2009, one in six (17%) non-Hispanic black children had asthma.

Ozone smog boosts hospital admissions for respiratory illnesses. A 2011 analysis looked at nearly 100 prior ozone studies and found that for kids, there was a 3.67% increase in risk of asthma emergency department visits for every 10 parts-per-billion increase in average daily ozone concentrations. Even very low concentrations of ozone can be harmful to health, so it makes sense to do everything we can to lower concentrations in the air we breathe.

There will be a joint hearing today of two Senate subcommittees on the subject of Air Quality and Children’s Health. The body of knowledge that’s been built on ozone is extremely relevant to today’s hearings, since the EPA is in the process of finalizing its reconsideration of the national ozone standards, whose goal under the Clean Air Act is to protect human health.

If children are our future, then we put that future in peril by turning a blind eye to the dangers that air pollution poses to children’s health.

This article originally appeared on the NRDC blog, Switchboard.