Comment on "Effect of nitrogen oxide emissions on ozone levels in metropolitan regions", "Effect of nitrogen oxide (NOx) emission rates on smog formation in the California South Coast Air Basin", and "Effect of hydrocarbon and nitrogen oxide (NOx) on photochemical smog formation under simulated transport conditions"

Abstract. This work presents results from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) study. Whole air samples were obtained on board research flights that flew over California during June 2008 and analyzed for selected volatile organic compounds, including several halogenated species. Samples collected over the South Coast Air Basin of California (SoCAB), which includes much of Los Angeles (LA) County, were compared with samples from inflow air masses over the Pacific Ocean. The levels of many halocarbon species were enhanced significantly over the SoCAB, including compounds regulated by the Montreal Protocol and subsequent amendments. Emissions estimates of HFC-152a (1,1-difluoroethane, CH3CHF2; 0.82 ± 0.11 Gg) and HFC-134a (1,1,1,2-tetrafluoroethane, CH2FCF3; 1.16 ± 0.22 Gg) in LA County for 2008 were obtained using the observed HFC:carbon monoxide (CO) enhancement ratio. Emission rates also were calculated for the SoCAB (1.60 ± 0.22 Gg yr−1 for HFC-152a and 2.12 ± 0.28 Gg yr−1 for HFC-134a) and then extrapolated to the United States (32 ± 4 Gg yr−1 for HFC-152a and 43 ± 6 Gg yr−1 for HFC-134a) using population data. In addition, emission rates of the two HFCs in LA County and SoCAB were calculated by a second method that utilizes air quality modeling. Emissions estimates obtained using both methods differ by less than 25% for the LA County and less than 45% for the SoCAB.

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HFC-152a and HFC-134a emission estimates and characterization of CFCs, CFC replacements, and other halogenated solvents measured during the 2008 ARCTAS campaign (CARB phase) over the South Coast Air Basin of California

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-28017-2010 ◽

2010 ◽

Vol 10 (11) ◽

pp. 28017-28056

Author(s):

B. Barletta ◽

P. Nissenson ◽

S. Meinardi ◽

D. Dabdub ◽

F. Rowland ◽

...

Keyword(s):

Los Angeles ◽

Population Data ◽

Montreal Protocol ◽

South Coast ◽

Emission Rates ◽

The South ◽

The Pacific ◽

Hfc 134A ◽

South Coast Air Basin ◽

Hfc 152A

Abstract. This work presents results from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) study. Whole air samples were obtained on board research flights that flew over California during June 2008 and analyzed for selected volatile organic compounds, including several halogenated species. Samples collected over the South Coast Air Basin of California (SoCAB), which includes much of Los Angeles (LA) County, were compared with samples from inflow air masses over the Pacific Ocean. The levels of many halocarbon species were enhanced significantly over the SoCAB, including compounds regulated by the Montreal Protocol and subsequent amendments (e.g., enhancements of 13 pptv and 11 pptv for CFC-11 and CFC-12, respectively). Emissions estimates of HFC-152a (0.98±0.05 Gg) and HFC-134a (1.40±0.11 Gg) in LA County for 2008 were obtained using the observed HFC:CO enhancement ratio. The emission rates were extrapolated to the SoCAB (1.48±0.07 Gg for HFC-152a and 2.12±0.17 Gg for HFC-134a) and US (30.1±1.5 Gg for HFC-152a and 43.0±3.4 Gg for HFC-134a) using population data. In addition, emission rates of the two HFCs in LA County and SoCAB also were calculated by a second method that utilizes air quality modeling. Estimates obtained using both methods agree well.

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Study of Real-road Nitrogen Oxide Emissions of Non-road Vehicles

Journal of Physics Conference Series ◽

10.1088/1742-6596/2160/1/012050 ◽

2022 ◽

Vol 2160 (1) ◽

pp. 012050

Author(s):

Piqiang Tan ◽

Junwen Yao ◽

Chaojie Yao ◽

Zhiyuan Hu ◽

Diming Lou ◽

...

Keyword(s):

Nitrogen Oxide ◽

Nox Emission ◽

Emission Measurement ◽

Nox Emissions ◽

Nitrogen Oxide Emissions ◽

Road Vehicles ◽

The Real ◽

Portable Emission Measurement System ◽

Data Processing Method ◽

Variation Trends

Abstract The exhaust gas pollutants of the non-road vehicles are harmful to the environment. Many non-road vehicles meet the requirements of the regulations in the laboratory. However, the real-road emissions of such vehicles are sometimes higher. Measuring the real-road emissions of non-road vehicles is very important. The real-road emissions are measured by on-Board Diagnostics (OBD), but there are some problems in the data stability of OBD. The NOx emissions of a bulldozer (a type of China IV non-road vehicle) based on both portable emission measurement system (PEMS) and OBD are studied in this article. Experiments contained three working processes: idle, driving, and operating. The nitrogen oxide (NOx) emissions during operating were highest. The NOx emission characteristics of the bulldozer from PEMS and OBD have the similar variation trends. But there are still some differences, including the NOx emission value and response time. The measurement principles and different sampling points between PEMS and OBD are the main factors. An effective data processing method is introduced to reduce the differences of between the data from PEMS and OBD. Briefly, the NOx emissions of the OBD and PEMS were highly consistent. The OBD is reliable and can be widely used in non-road vehicles.

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