If air quality is extremely important to you, the Atmotube pollution sensor is the portable gadget you're going to want to add to your arsenal. Currently in the midst of a crowdfunding campaign on Indiegogo, the air pollution monitor is a personal device that helps you to breath in cleaner air.
This is perfect for people who live in cities where air pollution is a bigger problem, as well as those suffering from asthma or allergies. The sleek design of the pollution sensor makes it less obtrusive to carry around as it easily clips onto your personal effects, like a purse or backpack.
The 'holistic parameter' measures air quality, which you can read more into using the accompanying app. It also works indoors.