1. Environmental ProblemsThe environment is our physical surroundings. This includes both human (man-made), social and physical (natural) features. Natural features include soil, the atmosphere, vegetation and wildlife. Human features include housing, transport and industry. Social features include things such as culture, language and political systems. Geographers are concerned about human action in the environment. Human interference with the environment causes problems such as soil erosion, global warming and acid. You may ask how we as individuals can have an impact on the environment. Our actions can help to increase and decrease the problems highlighted above. For example turning off lights that are not being used helps to reduce global warming.Questions：1What is the environment?2How can we help to decrease the global warming problems?Global WarmingGlobal warming is the worldwide warming of the atmosphere.To understand global warming you first need to know about the greenhouse effect. The greenhouse effect is a natural phenomenon that controls the balance of heat within the earths atmosphere. It is the process whereby the natural layer of gases in our atmosphere trap a small percentage of the suns radiation reflected from the earths surface. Without the greenhouse effect, the average surface temperature would be about -18 degrees Celsius.Global warming is caused by the increases in the amount of carbon dioxide and other gases being released into the atmosphere by the burning of fossil fuels. These gases add to the natural greenhouse effect. Causing global temperatures to rise.Questions：1.What is global warming?2.What causes global warming?Atmospheric particulate matterIn recent years,our country appear much haze weather,which is now often referred to PM2.5.Specifically,PM2.5 is in the atmosphere of diameter less than or equal to 2.5 micron particles,which is also known as enters the lung particle matter.Its diameter is less than the thickness of a human hair 1/20.Atmospheric particulate matter- also known as particulates or particulate matter(PM) - are tiny pieces of solid or liquid matter associated with the Earths atmosphere. They are suspended in the atmosphere asatmosphericaerosol, a term which refers to the particulate/air mixture, as opposed to the particulate matter alone. However, it is common to use the term aerosol to refer to the particulate component alone. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of particulates. Coal combustion in developing countries is the primary method for heating homes and supplying energy. Particulate matter emissions are highly regulated in most industrialized countries. Due to environmental concerns, most industries are required to operate some kind of dust collection system to control particulate emissions. These systems include inertial collectors (cyclone collectors), fabric filter collectors (baghouses), wet scrubbers, and electrostatic precipitators.Questions:1、1.What is Atmospheric particulate matter?2.What causes global warming?The acidity of acid rainAcidity in rain is measured by collecting samples of rain and measuring its pH. To find the distribution of rain acidity, weather conditions are monitored and rain samples are collected at sites all over the country. The areas of greatest acidity (lowest pH values) are located in the Northeastern United States. This pattern of high acidity is caused by the large number of cities, the dense population, and the concentration of power and industrial plants in the Northeast. In addition, the prevailing wind direction brings storms and pollution to the Northeast from the Midwest, and dust from the soil and rocks in the Northeastern United States is less likely to neutralize acidity in the rain. Questions：1.How do we measure the acidity of rain?2.How do the density of power plants affect acidic rain?4. The Greenhouse EffectGreenhouse effect is the effect produced by the accumulation of carbon dioxide crystals and water vapor in the upper atmosphere, which insulates the earth and raises the atmospheric temperature by preventing heat loss. Chlorofluorocarbons also help create the greenhouse effect.A number of gases in the atmosphere are transparent to incoming sunlight but absorb the heat emitted from the Earths surface and reradiate it in all directions, including back toward the surface. As a result, the surface is warmed more than it would have been in the absence of these gases, which serve a purpose similar to that of the glass walls of a greenhouse.Global warming refers to the enhancement of the natural greenhouse effect due to rising atmospheric