Anyone traveling to a national park in the hope of enjoying some fresh air may be disappointed. A study published in Science Advances looked at air pollution levels in Yellowstone, Grand Canyon, Yosemite, Glacier and 29 other parks, and it found that they differed little from those in the country's 20 largest metropolitan areas. The study focused on ozone levels, which are used in national parks to notify visitors of air quality conditions. They also counted the number of days in a year when ozone concentrations reached 70 parts per billion, a level the Environmental Protection Agency considers unhealthy for children and older people, and for anyone with lung disease.

Texting done right can improve your health

Texting gets blamed for everything from fostering social isolation to increasing teens' risk of ADHD to driving down adolescent self-esteem to damaging the spine. But some technological and medical experts say the negativity is unfair. Texting can and should be a positive force in people's lives so long as it's used correctly. If done well, MIT psychologist Sherry Turkle and other experts said, texting can improve interpersonal relationships, help people deal with traumatic events and bridge intergenerational gaps. There are also medical applications: Texting eases communication with doctors, advances research as an easy and accurate way of gathering patient information in scientific studies, and can offer support to at-risk or suicidal individuals.

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