Exposure

“Low-cost monitoring devices to vastly expand the amount of data that are publicly available on forms of air pollution such as particulate matter and toxic gases … are easy to deploy and can complement data from official networks. … Work is also under way to develop wearable sensors to monitor personal exposure levels.” (http://www.nature.com/news/environmental-science-pollution-patrol-1.16654)

Always check it’s safe before you expose yourself.