air pollution control

华东理工大学2015—2016学年第二学期《大气污染控制工程》课程论文 2016.4

班级环境133 学号10132228姓名周嘉昊

开课学院资环学院任课教师杨骥成绩

1.Introduction

From July 24 to Aug 8,2015, Shanghai had been suffering from ozone pollution for 11 days in row. Data from the Shanghai Environment Monitoring Center shows ozone pollution has been the primary pollutant in the city from July 24 to August 4. The most polluted day was August 4, when the air quality index (AQI) surged to 181.

As the main photochemically produced atmospheric constituent, surface ozone (O3) is a major pollutant that can cause serious damage to human health and ecological environment. Surface ozone is formed in the air as a result of complex photochemical reactions involving nitrogen oxides (NO + NO = NOx), carbon monoxide (CO), and various volatile organic compounds (VOCs), which mostly result from anthropogenic activities. The temporal variations of surface ozone have been widely studied for several decades. Many studies indicated that the temporal variations of ozone concentration have distinct regional characteristics.

Chief forecaster from the Shanghai Environment Monitoring Center, Duan Yusen, explained that ozone pollution is a result of air pollution from automobile exhaust and industrial emissions; under high temperature and sunny conditions, such as the summer days in Shanghai, nitrogen oxide gases and volatile organic compounds react chemically to form ozone.

Ozone protects people from ultraviolet rays if it is up in the atmosphere. However, people's health is severely threatened by close exposure to ozone. Potential symptoms arising from prolonged exposure to ozone include respiratory diseases, coughing and damage to the immune system.

Breathing masks cannot prevent ozone pollution. Environmental departments advise people to avoid outdoor activities when the pollution is the most severe between 2 to 3 o'clock in the afternoon. Ozone pollution is naturally relieved in September.

Shanghai, situated on the east coast of China, is a metropolis with a total population over 24 million as of 2013. The rapid growing urbanization causes wide-ranging consequences for the environment. One of the most serious environmental problems is the enhanced ozone concentration in Shanghai, so it is vital and urgent to gain a good understanding of ozone production in Shanghai.

2.Ozone basics

Ozone is a gas composed of three atoms of oxygen (O3). Ozone occurs both in the Earth's upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found.

Called stratospheric ozone, good ozone occurs naturally in the upper atmosphere,