# Air Quality Effects on Human Health and Approaches for Its Assessment through Microfluidic Chips
## 6 Summary  
Our body is in direct interaction with the air that surrounds us from birth until death. Throughout our entire evolution, humans have learned to cope with natural pollution sources, such as salt spray from the oceans, dust storms, wildfires, volcano eruptions, etc. Usually, natural pollution sources are temporal and do not last very long (such as wildfire), or are seasonally reoccurring (such as dust storms). Although natural pollution produces rather small particles [79; 99], which can be more deeply  
Figure 4: The Shanghai University (SHU) iSmart Institute cell culture room for the organ-on-chip (OoC) experiments. The area is isolated, with the high efficiency particulate air (HEPA) filtration, temperature and humidity control. The air pressure inside is kept positive to keep away the outside air. The cell culture room has an area of 30 m\({}^{2}\) (5 \(\times\) 6 m) and accommodates the instruments necessary for work: refrigerators, freezers, cell culture incubators, biological safety cabinet, microscope, and chip setup with fluid control. inhaled into lungs, and are therefore more dangerous, the natural pollutants are overall less toxic, regarding their chemical formula, compared to those of anthropogenic origin. Anthropogenic pollution affects the air quality both indoors and outdoors. Here, burning fossil fuels can be regarded as the main source of pollutants. Aside from SO\({}_{2}\), NOx, and other exhaust gases, there are many anthropogenic pollution formulations, such as POPs, that are persistent, and thus will affect our environment in the long-term. Of course, it is of high importance to identify sources of pollutants and to follow their migration patterns. On the global scale, large area sand storms, industrial gases, and other pollutants can be monitored with the help of satellites. Satellites can be equipped with various sensors, capable of detecting and quantifying the size and chemistry of particles. For example, a moderate resolution imaging spectroradiometer (MODIS) is used to gather information on various gases, including formaldehyde (CH\({}_{2}\)O) [8; 10]. On the ground level, the air quality in many cities is monitored with the help of meteorological stations. The data can be accessed in real time online; mobile phone applications are also available. For example, The World Air Quality Index project provides information from more than 70 countries by collecting and summarizing air pollution data from 600 major cities with more than 9000 stations in total (Figure 1) [11]. Indoor air can be monitored for various pollutants, such as CO\({}_{2}\) and VOCs, while conditioning systems can be adjusted to improve air quality. Additionally, the air inside houses or cars can be filtered through various filters (such as a High efficiency particulate air (HEPA) filter). There are many tools to monitor and improve air quality. The best solution is to understand the source of a particular pollutant and minimize its output. There are many examples of new and untested materials being introduced to our environment prematurely, and only in later steps, their hazardous potential is recognized, eventually leading to their complete ban. That happened with asbestos, which was popular until 1975 [61], POPs [91; 92], and others. Now, there are worldwide regulations in place, including a total ban on these substances. We predict the same may happen to the burning of coal and diesel fuel, as these fuels produce cancerogenic particles in the nanoscale size. We observe the constant progress towards a cleaner environment, fueled by the demands of an ever-increasing number of educated and concerned citizens who exert pressure on policy-making authorities. For example, in China, there are currently very few personal vehicles using diesel, with increasing popularity of silent and clean electric-powered cars and scooters. Small detection chips are gaining popularity in sensing various gases, particle size, and chemical composition of the air.