REVEAL II Data

DATA COLLECTED DURING REVEAL II

The REVEAL II measurement campaign was conducted during the period April 1994 - June 1995. During this field campaign instruments were deployed at a number of sites which are referred to throughout this document using unique 3,4 or 5 letter identifiers. The specifics of the data collection methods, analysis and site locations are provided here. The site locations are shown here.

REVEAL II DATA
The measurements conducted under REVEAL II may be summarized as follows:

AEROSOL: Measurement of the mass and composition of ambient aerosols.
Ambient aerosols were collected for chemical analysis using IMPROVE samplers at Clearbrook (CLBR) (1 km south of Abbotsford Airport), and Chilliwack (CHIL). Sampling occurred on Saturdays and Wednesdays. The IMPROVE Modular Aerosol Monitoring Sampler consists of four independent filter modules; one PM₁₀ filter sampling system and three PM_2.5 filter systems. The samplers used in REVEAL II were limited to the modules A, B and C which monitor only the fine particle fraction of the total aerosol loading. The filter samples were collected over a period of 24 hours so the sample is an integrated daily average. Description of the filter mediums, quantities measured and analytical techniques used for analysis are shown here.

OPTICAL: Measurement of the components of light extinction.
Optical characteristics of the atmosphere are typically (though not uniformly) assessed via measurement of the total light extinction (b_ext) (or b_sp). During REVEAL II, light scattering (b_scat) was measured using open-chamber nephelometers (Optec NGN-2) at CLBR and CHIL. Relative humidity and ambient dry-bulb temperature were also monitored at the nephelometer sites. Five minute averaged particle light scattering (b_sp) was measured at CHIL and CLBR using open chamber nephelometers and has been averaged to generate hourly values which are presented here. The data signals were processed and averaged to produce hourly average values.

SCENE: Monitoring of scene characteristics.
During REVEAL II photographs were taken from Abbotsford International Airport (AIA) (this site is refered to as ABB and was later moved to Matsqui Municipal Hall (MMH), CHIL, Hope (HOPE) and Mission (MISS). The automated camera systems were programmed to take three photographs each day: 9 am, noon and 3 pm (LT).

Five day enhancement period.
Data were collected during a "five day enhancement episode" in June 1995. The "five day enhancement episode" is an event specific monitoring intensive conducted to collect data more intensively during a period of reduced visibility. The change in instrumentation deployed was that the IMPROVE samplers were run to collect 6 hour average samples and a Davis Rotating-drum Universal-size-cut Monitoring impactors (DRUM) sampler (the DRUM sampler data is not available for analysis because of technical problems).

OTHER DATA CONTAINED IN THE REVEAL II DATABASE
In addition to data collected specifically for REVEAL II outlined above, the database also contains the following meteorological, aerosol and gaseous data collected by both local and federal agencies.

Hourly average PM₁₀ concentrations collected using TEOMs (Tapered Element Oscillating Micro-balance) at sites operated by the GVRD and BCMoELP.

Hourly average routinely collected meteorological observations (including wind speed and direction, surface pressure, relative humidity, temperature, cloud cover) from Vancouver International Airport (VIA) and Abbotsford International Airport (AIA) as operated by the Atmospheric Environment Service.

Hourly estimates of the visual range recorded routinely at Vancouver International and Abbotsford International Airports are also available for the duration of REVEAL II. Surface visibility as reported at airports such as Vancouver International and Abbotsford is a measure of the distance at which an observer can recognize specified objects (at known distances from the observer) with the naked eye, and is qualitative since it depends on the judgement and eyesight of the observer and the available checkpoints.

Hourly average gaseous concentrations (including ozone (O₃), sulphur dioxide (SO₂), oxides of nitrogen (NO_x) (nitrous oxide (NO) and nitrogen dioxide (NO₂)), carbon monoxide (CO)) from sites operated by the GVRD and BCMoELP.

Upper air data from the Quillayute radiosonde release site.