Featured Research

from universities, journals, and other organizations

Acid pollution in rain decreased with emissions, long-term study shows

Date:
November 17, 2011
Source:
University of Illinois at Urbana-Champaign
Summary:
Emissions regulations do have an environmental impact, according to a long-term study of acidic rainfall. A report detailing trends in acidic rainfall frequency and concentration over 25 years found that as sulfur and nitrogen emissions have dropped in response to the Clean Air Act, acid ions in rainwater have dropped by similar magnitudes.

The mean concentration of sulfuric acid ions in rainwater in 1985 (top) and 2008, as measured by the National Atmospheric Deposition Program's network of collection sites across the United States.
Credit: National Atmospheric Deposition Program, Illinois State Water Survey

Emissions regulations do have an environmental impact, according to a long-term study of acidic rainfall by researchers at the University of Illinois.

The National Atmospheric Deposition Program collects rainfall samples weekly from more than 250 stations across the United States and analyzes them for pollutants. The program recently released a report detailing trends in acidic rainfall frequency and concentration over 25 years, from 1984 to 2009.

"This is the longest-term, widest-scale precipitation pollution study in the U.S. In particular, we wanted to see how the trends in the pollution and the rain correlated back to emissions regulations," said Christopher Lehmann, a researcher in the program, which is part of the Illinois State Water Survey at the U. of I. "We're seeing regulations on emissions sources having direct and positive impact to reduce pollutants in rain."

The phenomenon commonly known as "acid rain" has widespread effects not only on the ecosystem, but also on infrastructure and the economy. Polluted precipitation adversely affects forestry, fishing, agriculture and other industries. Acid also erodes structures, damaging buildings, roads and bridges.

According to the report, acidic precipitation -- rain or snowfall with a pH value of 5.0 or less -- decreased in both frequency and concentration over the 25-year span.

The researchers largely attribute the decrease to the amendments to the Clean Air Act in 1990 regulating emissions of sulfur dioxide and nitrogen oxide, the gases that become sulfuric and nitric acid when mixed with rain water.

"What goes up does come down," Lehmann said. "Rainfall chemistry directly correlates with air pollution. When we looked at the magnitude of the trend, we found it compared very well to the magnitude of the decrease in emissions reported by the EPA (Environmental Protection Agency)."

According to EPA data, sulfate emissions dropped more than 50 percent during the period covered by the study and nitrate emissions dropped more than 30 percent. The National Atmospheric Deposition Program report found that concentrations of corresponding acid ions in rainwater have dropped by similar magnitudes. In addition, frequency of acidic precipitation has decreased across the U.S.

"You want to make sure that the regulations you put in place are effective, that they do what they were designed to do," said David Gay, the coordinator of the deposition program. "That's why we're here. We spend a lot of money to promulgate regulations. There's a lot of concern about their impact on industry. This study shows clear, significant evidence of the direct impact of regulation."

The deposition program continues to monitor sulfur and nitrogen compounds in rain. Although acidic precipitation has decreased, it has not disappeared, particularly remaining prevalent across the eastern U.S. In addition, the program has expanded its screening and monitoring other problematic pollutants such as ammonia and mercury.

"We still have acid rain," Lehmann said. "Yes, the trend is down, and we should celebrate that, but it's still a problem. There is still progress to be made, and there are new regulations coming along to continue to reduce emissions of sulfur and nitrogen compounds."

The Illinois State Water Survey is a unit within the Prairie Research Institute at the U. of I.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Journal Reference:

  1. Christopher M. B. Lehmann, David A. Gay. Monitoring Long-Term Trends of Acidic Wet Deposition in US Precipitation: Results from the National Atmospheric Deposition Program. PowerPlant Chemistry, 2011; 7 [link]

Cite This Page:

University of Illinois at Urbana-Champaign. "Acid pollution in rain decreased with emissions, long-term study shows." ScienceDaily. ScienceDaily, 17 November 2011. <www.sciencedaily.com/releases/2011/11/111116162244.htm>.
University of Illinois at Urbana-Champaign. (2011, November 17). Acid pollution in rain decreased with emissions, long-term study shows. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2011/11/111116162244.htm
University of Illinois at Urbana-Champaign. "Acid pollution in rain decreased with emissions, long-term study shows." ScienceDaily. www.sciencedaily.com/releases/2011/11/111116162244.htm (accessed September 19, 2014).

Share This



More Earth & Climate News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins