Source: Earth PD http://bit.ly/1ESoBKp
Hi, I'm Jensen Morgan. We're going to talk about some great concepts in environmental science. Today's topic is efforts to address air pollution, so let's get started. We're going to talk about the history of US attempts to address air pollution, US policy surrounding air pollution mitigation, and improvements that have been made as a result of regulation.
Since the beginning of the Industrial Revolution, pollution has been a human and environmental health problem, yet little has been done at the federal level to address it until recent years. In 1948, over a period of five days a warm pocket of air trapped colder air over Donora, Pennsylvania. This led to a thick smog from nearby zinc and steel smelting factories. It caused the deaths of 40 people. Half of the town of to Donora, about 14,000, experienced respiratory and cardiovascular health problems.
As a result of this event and many others that led up to 1970, the US declared the first Earth Day in response to increased public awareness of environmental issues caused from human activities. Until the late 1960s and early 1970s, states had primarily dictated air pollution regulation, but as public concern steadily grew, federal government began to step in. The first significant federal act related to monitoring air pollution is the Motor Vehicle Pollution Control Act of 1965, which began setting emission standards for vehicles.
In 1970, the US government approved the Clean Air Act, which charged the Environmental Protection Agency, also called EPA, with identifying air pollutants from stationary and mobile sources that may reasonably be anticipated to have negative impacts on public health and welfare. The initial list they came up with included sulfur dioxide, nitrogen oxides, total suspended particulates-- which was changed in 1987 to PM10 to represent particulate matter that is 10 micrometers or less-- carbon monoxide, and ozone. By 1987, lead was added to this list as well, and in 2007 the US Supreme Court ruled that greenhouse gases were also to be covered and managed by the Clean Air Act.
The Clean Air Act creates limits to the amount of air pollutants from mobile and stationary sources, as well as regions, that can be emitted. On mobile sources, the Clean Air Act mandated that by 1975 automobile manufacturers had to cut emissions by 90% in all new cars. On stationary sources, it mandated that the EPA set performance standards for all major categories of stationary sources. And it mandated that regional limits be met for ambient air quality in all regions and counties. These limits did not vary by region, which makes it difficult for areas with higher amounts of pollution.
As time has passed, standards have been added for newer sources of pollution which are even stricter than past standards for older sources at the passing of the Clean Air Act. The US EPA sets the national standards for pollutants and their allowable levels based off of the Clean Air Act. The EPA standards are geared at protecting public health and welfare against any known negative effects of listed pollutants.
An important organization to also note is OSHA. Or Occupational Safety and Health Administration, which regulates permissible levels of indoor air pollutants in places of work. There are currently are no regulatory agencies which manage air pollution in residences.
As a result of regulation, improvements air quality have been made. There has been a reduction in certain regulated pollutants despite increases in energy use, vehicle miles traveled, and economic activity. Causes of these improvements resulting from regulation and/or technology advancement are smaller cars, more efficient engines, improved gas mileage, and decreased emissions from energy plants and factories.
Levels of nitrogen oxides, sulfur dioxide, carbon monoxide, lead, and particulate matter of all decreased. Unfortunately, there has not been significant progress in ground-level ozone reduction. Only 15% of the US population, about 50 million, live in areas with air pollution levels above ambient air quality standards.
Now let's have a recap. Today we talked about the recent history of efforts to address air pollution in the US, policy and regulations such as the Clean Air Act of 1970 that have been passed a manage air pollution, and current improvements that have been made as a result of those efforts. Well, that's all for this tutorial. I hope these concepts have been helpful and I look forward to seeing you next time. Bye.