• Map: Plume Labs' World Air Map provides a realtime snapshot of air pollution in major cities around the world.

Air pollution is largely invisible, affects everyone's health, and is mostly out of any single person's control. But tech company Plume Labs wants to empower people to make smarter decisions with its World Air Map, which shows realtime air quality around the world.

The data comes from local monitoring stations in over 150 cities. While these results are already released publicly, the desktop-based World Air Map and companion smartphone app aim to put the information in context and make it more accessible.

The mobile application is especially useful for those in high-pollution spots or for people with chronic health conditions who are particularly sensitive to pollution. It delivers alerts about pollution levels in the user's city, and can even predict the best time to plan outdoor exercise. For the fair-skinned among us (hi!), it also includes a UV index.

Canadian cities tracked include Toronto, Ottawa, Vancouver, Montreal, and Hamilton.

Worldwide, the World Health Organization (WHO) estimates that 3.7 million people die prematurely every year from outdoor air pollution, with the vast majority of deaths (88 per cent) happening in developing countries.

According to WHO, the pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide.

Cars, industrial facilities and forest fires are all common sources of air pollution, which can increase the risk of respiratory and heart disease, especially among children and the elderly.