USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics

Air Quality: Smoke Effects

Smoke emissions, ozone, and regional haze

Wildfire smoke, Idaho. Photo credit: NFIC
Photo credit: NFIC

Evaluation of landscape level spatial distribution of air pollutant concentrations and deposition to forests, other natural ecosystems and agricultural systems is important for risk evaluation and proper planning of management practices such as prescribed fires. Fire emissions may combine with urban pollution to impact regional haze and visibility in Class I areas distant from fires. The Grand Canyon Visibility Transport Commission (GCVTC) concluded in its analysis that for the Colorado Plateau "emissions from fire, both wildfire and prescribed fire, are likely to have the single greatest impact on visibility in Class I areas through 2040". Wildfire emissions also promote the formation of ozone (O3 ), a criteria pollutant affecting human health and agricultural and natural vegetation. Current monitoring systems for air pollutants are expensive. Robust low-cost sampler systems are needed to increase spatial and chemical resolution of air quality data, especially for Class I areas.

 NOAA Satelite photo of McNally fire smoke over the Sierra Nevada in California

Smoke plume from the McNally fire in the Southern Sierra Nevada,
July, 2002. Photo credit: NOAA
Full size image (opens new window)

Recent research indicates that various filter pack, denuder and passive monitoring systems can be used in monitoring a wide spectrum of air pollutants in remote locations. We are working on the adaptation and evaluation of robust low-cost sampler systems to measure gaseous and particulate pollutants, that are the major contributors to large-scale air pollution problems, including regional haze.

 Ozone and Nitric Acid passive samplers deployed on a poleOzone, nitrogen oxides, ammonia, and nitric acid vapor passive samplers deployed on a pole.

 Ion exchange resin throughfall collectorIon exchange resin column throughfall collector for measuring nitrogen and sulfur deposition.

Smoke emissions, nitric acid vapor, and N deposition

Concentrations of nitric acid vapor, similar to those of ozone, increase downwind from forest fires. Nitric acid vapor is an important component of dry deposition of nitrogen (N) to forests. Because of the widespread and largely detrimental effects of elevated atmospheric N deposition, quantification of ecosystem N inputs from air pollution are needed. Throughfall collection and analysis has a great potential for widespread monitoring, however, conventional throughfall methods are expensive and time consuming. We have developed throughfall collectors based on ion exchange resin columns that function under field conditions for as long as one year.

Reports and Publications

Improving Model Estimates of Smoke Contributions to Regional Haze Using Low-cost Sampler Systems
Funding: Joint Fire Science Program
Duration of the Project: September 19, 2001- April 30, 2004

In this study, state-of-the-science active and passive systems for monitoring gaseous pollutants were evaluated, as well as an alternative method of measuring N deposition in throughfall. GIS methods were used to produce mapped distributions of summer 2002 ambient ozone in selected areas of the Sierra Nevada Mountains using a combination of passive ozone samplers and active monitor data.

Research conducted by:
Last Modified: Mar 28, 2013 03:39:02 PM