The effects of NO2-aerosol interaction on indices of perceived visibility impairment

Haas, Peter J.; Fabrick, Allan J.

doi:10.1016/0004-6981(81)90248-1

Cited by 3 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Characteristics of clear air scattering are (1) the amount of scattered light varies as that of clear air for the 550-nm wavelength near sea level, results in a 10% reduction in radiance transmitted along a 10-km sight path. b ext usually is divided into the following four additive components: (1) clear air scattering, which depends on air density and thereby on pressure (elevation) and temperature; (2) gaseous absorption by NO 2 , which depends on NO 2 concentration and is typically negligible for regional haze but may be important for urban hazes 251,252 and in coherent plumes; (3) particle scattering from PM 2.5 and coarse (the difference between PM 10 and PM 2.5 ) mass fractions; and (4) particle absorption, which is dominated by soot, often termed black carbon (BC), elemental carbon (EC), or light-absorbing carbon (LAC).…”

Section: Table 2 (Cont) Visibility Metric and Methods Measurement Prmentioning

confidence: 99%

See 1 more Smart Citation

Visibility: Science and Regulation

Watson

2002

Journal of the Air & Waste Management Association

926

544

View full text Add to dashboard Cite

The 1999 Regional Haze Rule provides a context for this review of visibility, the science that describes it, and the use of that science in regulatory guidance. The scientific basis for the 1999 regulation is adequate. The deciview metric that tracks progress is an imperfect but objective measure of what people see near the prevailing visual range. The definition of natural visibility conditions is adequate for current planning, but it will need to be refined as visibility improves. Emissions from other countries will set achievable levels above those produced by natural sources. Some natural events, notably dust storms and wildfires, are episodic and cannot be represented by annual average background values or emission estimates. Sulfur dioxide (SO2) emission reductions correspond with lower sulfate (SO4(2-)) concentrations and visibility improvements in the regions where these have occurred. Non-road emissions have been growing more rapidly than emissions from other sources, which have remained stable or decreased since 1970. Simpler models representing transport, limiting precursor pollutants, and gas-to-particle equilibrium should be used to understand where and when emission reductions will be effective, rather than large complex models that have insufficient input and validation measurements. Examples of model-based source attribution show large differences among estimates from various modeling systems and with ambient measurements.

show abstract

Section: Table 2 (Cont) Visibility Metric and Methods Measurement Prmentioning

confidence: 99%

“…Integrating nephelometer [251][252][253][254][255][256][257][258][259] Targets are selected at known distances from an observer at an airfield. Nighttime targets require lights and may differ from daytime targets.…”

Section: -244mentioning

confidence: 99%

Visibility: Science and Regulation

Watson

2002

Journal of the Air & Waste Management Association

926

544

View full text Add to dashboard Cite

show abstract

“…The absorption efficiency for freshly emitted particles from traffic ba/mass was estimated as ~6 m2/g whereas at rooftop ba/mass was ~2.5 m2/g (13MM). Nitrogen dioxide absorption effects have been calculated for combinations of N02 and sulfate aerosol in power plant plumes (14MM).…”

Section: (6ll) the Chemical Mass Balance Technique Has Been Appliedmentioning

confidence: 99%