| People generally spend most of their time indoors. Indoor pollutants such as ozone and PM2.5 could adversely affect human health, particularly in relation to impaired lung function. For a realistic assessment of human exposure, both outdoor and indoor measurements of ozone and PM2.5 concentrations are required. The objective of this thesis is to provide reference data for people who want to improve the indoor air quality (IAQ) and reduce the personal exposure to ozone and PM2.5. Applying ultraviolet adsorption method and optical particle counting method, we carried out consecutive measurements on ozone and PM2.5 concentrations inside and outside a couple of student hostel room in Nanjing University. This room is full of natural ventilation and without any indoor pollution source. The research shows, in general, the indoor air pollutant concentration 24 hours a day is closely following that of the outdoor. The indoor ozone and PM2.5 concentrations can be a significant fraction of those outdoors and are highly dependent on the ventilation pattern. Our measurements show that the indoor/outdoor ratios for ozone and PM2.5 are 0.21-1.00, and 0.42-0.79, respectively. Specific as follows, when the door and window are both closed (ventilation rate is 0.66), the I/O ratios for ozone and PM2.5 are 0.26 and 0.49 and when the door is closed and the window is opened (ventilation rate is 1.32), the I/O ratios for ozone and PM2.5are 0.50 and 0.65. Thus this thesis discussed the effective methods to reduce indoor pollutant levels.In another core content, The correlation between near ground level ozone, PM2.5 and local meteorological factors (air temperature, air relative humidity and wind speed etc.) are analyzed based on the data of March 2015 to February 2016 from the nine environmental monitoring stations of Nanjing city. The research result shows that the concentration of outdoor ozone is positively correlated with the air temperature, wind speed while negatively correlated with the relative air humidity, and in particular, the influence of air temperature and relative humidity is more obvious; the negative correlation between outdoor PM2.5 mass concentration and temperature, wind speed and the positive correlation between outdoor PM2.5 mass concentration and air humidity are also found, wherein the influence of wind speed and relative humidity is significant.In addition, this thesis also selects the internal space of public transportin Nanjing city as the object of study, carries out investigation and analysis of the air pollutant concentration levels therein. As the process of transportation is involved, the according instruments are carried up and down the underground spaces, in buses and in subway trains to measure and collect ozone and PM2.5 concentration data. The study finds that the level of ozone concentration on the ground space is higher than those in the underground space, and it’s the opposite with PM2.5. As for the public transport, the ozone concentration in the street was the highest, followed by that in the bus, and in subway trains (precisely when passing through a tunnel) is the lowest. The level of PM2.5 concentrationin the bus is the highest; in subway trains is the lowest.In short, directing at the ozone and PM2.5 concentrations in the air that Nanjing people breathe, the thesis carries out consecutive measurements on indoor and outdoor concentrations of ozone and PM2.5; and analyse the influence of meteorological factor on local ozone and PM2.5 concentrations; launches investigation and analysis of air pollutant concentration levels within the microenvironment of public transport. It’s aimed to strengthen people’s awareness of in- and outdoor ozone and PM2.5 concentrations and improve the ability to predict and control the microenvironment air pollution levels; therefore this thesis has both realistic values in operation and professional meaning for further researches. |
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