March 1, 2013By: Alberto Bielsa, LibeliumSensor

Wireless sensor networks help to create Smart Cities, using a distributed network of intelligent sensor nodes to measure a variety of parameters, such as noise, temperature, ambient light levels, carbon monoxide concentration, and the availability and location of parking spaces, for efficient city management. The Smart Santander project—a collaboration between companies and institutions designed as a life-size laboratory for technology—is an example of a unified vision for technology to benefit the lives of city dwellers and all citizens.

Introduction
Approximately 75% of the population of the European Union lives in urban areas. The Smart City concept as the next stage in urbanization has gained ground with policy makers, leading to investment in human and social capital, resource management, and new developments in environmental sustainability. A Smart City can be considered as an ecosystem, albeit one with highly technical components. This type of urban metabolism is an open and dynamic system that consumes, transforms, and releases materials and energy; develops and adapts to changes; and interacts with humans and other ecosystems.

Air pollution harms human health and the environment. Despite the fact that automobile and industrial emissions have decreased in recent years, air pollutant concentrations remain high and air quality problems persist. A significant proportion of Europe's population lives in areas, notably cities, where the air quality exceeds emission limits for several air pollutants that pose serious health risks: ozone, nitrogen dioxide, and particulate matter (PM). The danger is local, regional, and international because the atmospheric air currents may carry air pollution emitted in one country long distances to other locations, resulting in poor air quality there.

Environmental noise affects a large number of Europeans and the public perceives it as a major environmental problem. It can have physiological and psychological effects on people, interfering with basic activities such as sleep, rest, study, and communication.

In response to citizen demand and driven by the rising importance of three main aspects of governance, this new concept for cities is taking hold to a) offer a better quality of life, b) minimize environmental impacts, and c) reduce costs. The parking scenario involves all three factors. Throughout the world, atmospheric pollution and congested roads degrade the quality of life, resulting in lost time for drivers and wasted fuel. The European Commission estimates that economic losses due to traffic delays total €150 billion per year in Europe. The need to search for available parking spaces is a significant contributor to widespread congestion and a major cause of stress for motorists. Based on calculations in Barcelona, Spain, a million drivers spend an average of 20 minutes every day looking for a parking spot, producing 2,400 tons of carbon dioxide emissions while doing so.