Editorial commentary: Scanning for threats and natural environments giving our reptilian brains a break

Some scholars question these mechanisms, citing research that shows that in urban street canyons under specific geometric conditions trees can contribute to poor air quality by inhibiting pollutant dispersion or fueling ozone formation through emission of volatile organic compounds [10]. Together, these theories point to nature's ability to enhance vigilance, which describes resilience to the scanning for potential threats or dangers – or inversely, searching for safety cues in the environment [18,19]. Because people learn to recognize safety cues in environments where they grew up [15], lack of personal experience in nature may explain why some people do not recover from stressful experiences after nature exposure [20]. [...]greenspace shows a high return-on-investment [27,28] and there is growing evidence linking it to human health [11].