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Our series Healthy Planet, Healthy You explores just how tightly human health and environmental health are intertwined—for better and for worse. Each month, we’ll share the latest news on how nature can rejuvenate us on one hand and damage our health when it’s not cared for on the other. We’ll end with timely tips and tools to help you care for your environment so it can care for you.

Air pollution clearly threatens cardiorespiratory health, but its impact on hormones is less clear-cut. This study out of Anhui, China monitored how certain pollutants (particulate matter and sulfur dioxide) impacted reproductive hormones in women receiving fertility treatments. Researchers found that those who lived in an area with more air pollution had lower levels of estradiol and progesterone—hormones that are critical for supporting pregnancy. Interestingly, though, access to green space seemed to mitigate some of the negative effects. (Read the study here1.)

In most research on nature’s health benefits, data collection happens within a short time window. This unique longer-term study collected data on 2,699 adults in the Netherlands multiple times between 2010 and 2016. It found that over the course of six years, those who spent more time in “blue spaces” (by the coast, on a lake, etc.) reported significant mental health improvements—even more than those who paid more visits to green spaces like parks. (Read the study here2.)

While blue and green space seems to improve mood and brain health, grey space—built surfaces such as concrete, streets, or rooftops—might harm it. New research on children (average age of 10) found that kids who were surrounded by more grey space had increased connectivity of the left amygdala. This is not a positive thing, as researchers note that increased connectivity in this region may enhance the risk for emotion dysregulation. This underscores the importance of letting children explore nature whenever possible. (Read the study here3.)

A massive study on nearly 2 million Danish adults over 50 found that those exposed to three factors—pollution, traffic noise, and the built environment/ lack of green space—were more likely to have a heart attack over a 5-year study period. Air pollution was the most tightly correlated with heart attack risk, but all three factors seemed to be risky on their own, too. (Read the research here.)

Monthly focus: Tone down your “auditory diet”

As shown in the studies above, many parts of the built environment can increase our stress, dampen our mood, and ultimately put us at risk for certain chronic diseases. Some of these exposures are out of our immediate control. However, noise pollution is one thing we can avoid to an extent—even in busy cities.

This month, think about the sounds that you engage with on a daily basis. Do you constantly listen to music or podcasts, or do you carve out some time for quiet? Are you surrounded by traffic noise all day, or do you take the occasional trip to a quiet local park or coastline? Consider how the noises in your life affect your temperament, and consider adding some more silence and nature sounds to your auditory diet (even if they’re virtual).