Christopher M B Lehmann

• University of Illinois Urbana-Champaign

Ammonia (NH3) emissions from fertilizer application is a highly uncertain input to chemical transport models (CTMs). Reducing such uncertainty is important for improving predictions of ambient NH3 and PM2.5 concentrations, for regulatory and policy purposes and for exploring linkages of air pollution to human health and ecosystem services. Here, we...

The objective of this research is to quantify NH 3 flux above an intensively managed cornfield in the Mid-western United States to improve understanding of NH 3 emissions and evaluations of new and existing emission models. A relaxed eddy accumulation (REA) system was deployed above a corn canopy in central Illinois, USA (40 • 3 46.209 N, 88 • 11 4...

This study evaluated ammonia concentration variability at a street with heavy traffic in a São Paulo summer season from November 9 to December 17, 2013. Ammonia concentrations were measured by a Picarro G2103 continuous monitor (3s time resolution). The hourly NH3 concentrations showed a relationship with traffic, presenting maximum values between...

Background/Question/Methods Since 1978, the National Atmospheric Deposition Program (NADP) has tracked the status and changes in the many different chemical compounds within precipitation across the continent. The NADP monitors the removal of pollutants from the atmosphere; but more importantly, it monitors the addition of chemical compounds into...

Air quality and precipitation chemistry (wet deposition) of Metropolitan Area of Sao Paulo (MASP) and Cubatão, one characterized by a large vehicle fleet (Sao Paulo), and the other for the large industrial complexes (Cubatão). Concentrations of sodium, chloride, nitrate, calcium, and sulfate ions were higher in Cubatão than at MASP. In Cubatão, top...

Measuring wet deposition of organic carbon (OC) and black carbon (BC) is crucial for the complete understanding of the global circulation, lifetime, and radiative forcing of these aerosols. There is currently no accepted standard analytical method for measuring OC and BC concentration in precipitation. Different analytical methods have been employe...

Mercury (Hg) is a toxic metal that is found in aquatic food webs and is hazardous to human and wildlife health. We examined the relationship between Hg deposition, land coverage by coniferous and deciduous forests and average Hg concentrations in largemouth bass (Micropterus salmoides) equivalent fish (LMBE) in 14 ecoregions located within all or p...

Using the infrastructure of the National Atmospheric Deposition Program (NADP), numerous measurements of radionuclide wet deposition over North America were made for 167 NADP sites before and after the Fukushima Dai-ichi Nuclear Power Station incident of March 12, 2011. For the period from March 8 through April 5, 2011, wet-only precipitation sampl...

The need for ambient gaseous ammonia (NH(3)) measurements has increased in the last decade as reactive NH(3) concentrations and deposition fluxes show little change even with tightening standards on nitrogen oxides (NO(x)) emissions. Currently, there are several networks developing methods for adding NH(3) measurements in the U.S. Gaseous NH(3) mea...

Precipitation chemistry and depth measurements obtained by the Canadian Air and Precipitation Monitoring Network (CAPMoN) and the US National Atmospheric Deposition Program/National Trends Network (NADP/NTN) were compared for the 10-year period 1995-2004. Colocated sets of CAPMoN and NADP instrumentation, consisting of precipitation collectors and...

Approximately 80 different crop species are grown in the United States in widely differing geographic areas, climatic and edaphic conditions, and management practices. Although the majority of cultivated acreage in the United States is planted with only about 10 primary crops, uncertainties associated with trace gas emissions arise from: (1) limite...

Background/Question/Methods Since 1978, the National Atmospheric Deposition Program (NADP) has tracked the status and changes in the many different chemical compounds within precipitation across the continent. The NADP monitors the removal of pollutants from the atmosphere; but more importantly, it monitors the addition of chemical compounds into...

The use of post-consumer carpet as a potential fuel substitute in cement kilns and other high-temperature processes is being considered to address the problem of huge volumes of carpet waste and the opportunity of waste-to-energy recovery. Carpet represents a high volume waste stream, provides high energy value, and contains other recoverable mater...

Data from the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) indicate significant changes have occurred in precipitation chemistry and the chemical climate in the United States (US). A Seasonal Kendall Trend (SKT) analysis shows statistically significant increases in precipitation ammonium concentrations at 64% of 159 co...

A Seasonal Kendall Trend (SKT) test was applied to precipitation-weighted concentration data from 164 National Atmospheric Deposition Program National Trends Network (NADP/NTN) sites operational from 1985 to 2002. Analyses were performed on concentrations of ammonium, sulfate, nitrate, dissolved inorganic nitrogen (DIN, sum of nitrogen from nitrate...

An electrothermal-swing adsorption system was demonstrated on the bench scale for capture and recovery of organic vapors from air streams. Methyl propyl ketone (MPK), methyl ethyl ketone, n-hexane, acetone, and methylene chloride were removed and recovered at 200-1,020 ppm(v) in a 40.0 slpm air stream while using activated carbon fiber cloth (ACFC)...

There is a potential for using waste tire rubber to make activated-carbon adsorbents for air-quality control applications. Such an approach provides a recycling path for waste tires and the production of new adsorbents from a low-cost waste material. Tire-derived activated carbons (TDACs) were prepared from waste tires. The resulting products are g...

Activated carbons for natural gas storage were produced from Illinois bituminous coals (IBC-102 and IBC-106) and scrap tires by physical activation with steam or CO2 and by chemical activation with KOH, H3PO4, or ZnCl2. The products were characterized for N2-BET area, micropore volume, bulk density, pore size distribution, and volumetric methane st...

For more than a quarter century, the National Atmospheric Deposition Program - National Trends Network (NADP-NTN) has measured the acids, nutrients, and base cations in U.S. precipitation. NADP-NTN data are used to evaluate regional and seasonal variations and long-term trends in precipitation chemistry. Trends result from the combined effects of c...