Many people take the air they breathe for granted. Fumes and pollutants from industrial sites, diesel engines, and the burning of coal combine to form a thick, dusty haze that hangs over many of the world’s major urban centers, and the residents of rapidly-growing low-income cities pay the heaviest price.
On a short-term basis, poor air quality can dry out and irritate the eyes, nose and throat; cause headaches, congestion, and coughing; and trigger allergies and asthma attacks. Longer-term exposure is linked to lung diseases such as asthma and emphysema, certain types of cancer, nerve and organ damage, and even birth defects. Air pollution is one of the world’s most serious public health threats. One study found that annual deaths from air pollution in Africa increased by 36 percent from 1990 to 2013.
In addition to toxic fumes such as nitrogen dioxide, which is a by product of burning fuel, air pollution contains particulate matter such as dust and soot. WHO air quality guidelines measure concentrations of both coarse particulate (PM10, or particles between 2.5 and 10 micrometers in size) and fine particles (PM2.5, with particle sizes of less than 2.5 micrometers). Coarse particulate comes from sources such as road dust and construction, while fine particulate is primarily from combustion. The latter is particularly dangerous, since it can be inhaled deeply into the lungs.
Cities may have entirely different rationales in mind when they deploy some of the energy-saving and mobility applications explored in this report, but they could wind up improving air quality as a secondary benefit. It is estimated that these applications could lower average annual PM2.5 concentrations by some 3 to 6 per cent.
Cities that want to make a conscious effort to improve air quality can opt for another type of application: real-time information about air quality based on connected sensors throughout the city that capture real-time readings about the extent, sources, and daily fluctuations of pollution levels. Cities can act on this evidence in multiple ways to reduce pollution, and although these choices are informed by data, the solutions themselves do not always involve technology. Local officials can temporarily shut down plants and facilities that are heavy polluters, for example. When Santiago took these types of steps, the city was able to bring down PM10 concentrations by some 20 per cent. Beijing has similarly achieved a roughly 20 percent reduction in deadly airborne pollutants less than a year after it began closely tracking the sources of pollution and regulating traffic and construction accordingly.
Governments might also undertake more ambitious and longer-term interventions. Some involve heavy capital investment, such as expanding public transit to take more private vehicles off the road. Others involve new types of regulation, such as fuel and filtering standards. The ports of Los Angeles and Long Beach, for example, are southern California’s largest source of both air pollution and emissions. They achieved dramatic reductions after the 2006 introduction of a clean air plan that required cargo ships to shut down diesel engines and phased out the oldest and most polluting diesel trucks. Now they are seeking to go further with a new plan to gradually phase out all diesel trucks and shift to zero-emissions cargo handling equipment by 2020—moves that will require an estimated $14 billion in public and private funding.
In addition to facilitating measures to decrease pollution levels, real-time air quality information can be used in another important way: to mitigate negative health effects. People who are aware of air pollution levels can take their own protective measures. They may decide to wear masks, move their exercise indoors, or change their route to work. Those with asthma may decide not to go out at all.
In addition to public information about air quality, private apps such as Plume (which pairs devices with smart phones) offer users hyper-local information and behavioral advice. Especially in cities where solid fuels are often burned indoors for heat and energy, the health burden from indoor pollution may be just as significant as that from outdoor air pollution. Real-time information about air quality can help individuals respond both in and outside of the home, whether they change outdoor running paths, install range hoods in their kitchens, or dissuade family members from smoking.
MGI Smart Cities report estimate that this information can help reduce the negative health effects from air pollution by 3 to 15 per cent in the three cities analyzed, which could contribute to lowering the total disease burden by up to 1 per cent. In some Asian and Middle Eastern cities where air pollution accounts for more than 10 per cent of the city’s disease burden, real-time information could deliver even higher impact. Just as energy-saving and mobility applications could have spill over effects on air quality, air quality applications would have spill over effects on both GHG emissions and health outcomes. These types of multifaceted effects show the importance of thinking holistically about what it means to be a smart city and measuring outcomes in a broader and more dynamic way.