1. Introduction and Motivation
The presence of particulates, biological molecules, or other harmful materials in the Earth's atmosphere causes air pollution, which leads to diseases, human casualties, and damage to other living organisms such as animals and food crops, or to the natural or built environment. Air pollution may originate from anthropogenic or natural sources [1]. Large-scale industry, which is increasingly positioned outside metropolitan regions and urban areas, is not considered to be the primary source for the inferior air quality. Recent studies indicate that road traffic is the main source of urban air pollution. Road transport is responsible on average for 25% of all harmful emissions in Europe. In many EU countries this value is higher than 30%. The loss of environmental quality, together with the environmental impact of air quality, especially in large cities, both on the health and the welfare of people is one of the greatest threats of this century [2], [3]. According to EU official figures, about 225 000 people die from diseases, caused by car emissions in Europe every year. To combat this threat, the European Union has introduced stricter laws and intends to reduce car emissions by 20% by 2020 [4]. Advances in embedded systems and new gas sensors technologies provide an opportunity for a new generation of low-cost air quality monitoring systems to emerge. Low cost air quality sensors are the force that drives the development of emerging electronic technologies, which are increasingly widely accepted and implemented. The number of those commercially available devices has increased dramatically over the last five years although the quality of the data which they provide is still questionable [4]. The main goal of our study is to develop low-cost, mobile, air quality sensor nodes and to investigate whether such systems can provide reliable results and indications about air quality and can be used in practice. This approach should provide easier access to air quality monitoring data to a wider audience of citizens, scientists and control authorities.