The State of the Air 2016
The "State of the Air 2016" found continued improvement in air quality in 2012-2014, showing lower levels of year-round particle pollution and ozone. Still, more than half of all Americans—166 million people—live in counties where they are exposed to unhealthful levels of these pollutants.
The "State of the Air 2016" report shows that cleaning up pollution continues successfully in much of the nation. In the 25 cities with the worst pollution, the majority saw improvements from last year. Many saw their lowest levels ever of year-round particle pollution or ozone pollution.
State of the Air 2016 shows that more than one in two people had unhealthy air quality in their communities.
Yet, even as most cities experienced strong improvement, too many cities suffered worse episodes of unhealthy air. While most of the nation has much cleaner air quality than even a decade ago, a few cities reported their worst number of unhealthy days since the report began, including some that experienced extreme weather events. The "State of the Air 2016" report provides evidence that a changing climate will make it harder to protect human health.
The "State of the Air 2016" report shows that, even with continued improvement, too many people in the United States live where the air is unhealthy for them to breathe. Despite that continued need and the nation's progress, some people seek to weaken the Clean Air Act, the public health law that has driven the cuts in pollution since 1970, and to undermine the ability of the nation to fight for healthy air.
The "State of the Air 2016" report looks at levels of ozone and particle pollution found in official monitoring sites across the United States in 2012, 2013, and 2014. The report uses the most current quality-assured nationwide data available for these analyses.
The report examines particle pollution (PM2.5) in two different ways: averaged year-round (annual average) and over short-term levels (24-hour). For both ozone and short-term particle pollution, the analysis uses a weighted average number of days that allows recognition of places with higher levels of pollution. For the year-round particle pollution rankings, the report uses averages calculated and reported by the U.S. Environmental Protection Agency (EPA). For comparison, the "State of the Air 2015" report covered data from 2011, 2012, and 2013. More details about this process is in Methodology.
Thanks to stronger standards for pollutants and for the sources of pollution, the United States has seen continued reduction in ozone and particle pollution as well as other pollutants for decades. Figure 1 from EPA shows that since 1970, the air has gotten cleaner while the population, the economy, energy use and miles driven increased greatly. As the economy continues to grow, overall air emissions that create the six most-widespread pollutants continue to drop.
Overall, the best progress came in the continued reduction of ozone and year-round particle pollution, thanks to cleaner power plants and increased use of cleaner vehicles and engines. Continued progress to cleaner air remains crucial to reduce the risk of premature death, asthma attacks and lung cancer. However, a changing climate is making it harder to protect human health.
Many cities reduced their ozone pollution in 2012-2014 below that reported in 2011-2013. In 2015, the U.S. Environmental Protection Agency (EPA) updated and strengthened the national ozone standard, officially recognizing that ozone is unhealthy to breathe at lower levels than previously thought. In preparing "State of the Air 2016," the Lung Association reexamined all the ozone data for all prior years, back to 1996-1998 covered by the first report in 2000, using the new standard. Even using that more protective standard, six of the 25 most ozone-polluted cities reported their fewest unhealthy ozone days ever.
Sixteen of the most-polluted cities had their lowest year-round particle pollution levels in the history of this report. Still, some cities had higher year-round levels and one city reported its highest levels.
Unfortunately, many cities suffered more spikes in short-term particle pollution, particularly in the West, where continuing drought and heat may have increased the dust, grass and wild fires, while burning wood as a heat source appears to contribute to the problem in many smaller cities. Seven of the 25 most-polluted cities had their highest number of unhealthy days on average ever reported.
Still missing, however, are particle pollution data from all of Illinois and Florida and most of Tennessee because of problems with data processing in laboratories and other data issues. This means that no one knows if the levels of particle pollution were unhealthy in many cities that have historic problems with particle pollution, including Chicago and St. Louis.
Air pollution emissions have dropped steadily since 1970 thanks to the Clean Air Act. As the economy continues to grow, emissions that contribute to the most widespread pollutants continue to drop. (Source: U.S. EPA, Air Quality Trends, 2016.)
Los Angeles reported its best air quality ever in the history of the State of the Air report.
Los Angeles remains the metropolitan area with the worst ozone pollution, as it has for all but one of the 16 reports. However, Los Angeles reported its best air quality ever in the "State of the Air" report's history, with the lowest average year-round particles and fewest high-ozone and high-particle days. Bakersfield (CA) returned to the top of both lists for most polluted for particle pollution, thanks to worse year-round and short-term exposures.
Steps taken under the Clean Air Act have driven the cleanup of pollution seen in this year's report. Cleaning up power plants has helped drive the reduction in year-round particles and ozone, especially in the middle and eastern states. The retirement of old, dirty diesel engines has also reduced emissions.
At the same time, climate change has increased the challenges to protecting public health. The rise in short-term particle pollution provides current examples of how major changes in drought and rainfall are already affecting public health. Wildfires and drought, along with high use of wood-burning devices for heat, coupled with stagnant weather patterns that concentrated pollution in some areas, contributed to the extraordinarily high numbers of days with unhealthy particulate matter in 2012-2014.