Air quality monitoring
Discussion and planning stages only. Suitable sensor devices are being researched and several configurations of DIY devices are being prototyped. The aim is to provide Oberon with near real-time air quality monitoring data of adequate reliability and accuracy which anyone can access or view. More information and project plans will appear here in due course.
Introduction
Air quality monitoring is another project where Oberon Citizen Science Network (OCSN) can have a role to provide quality data to the community.
As a medium-sized population centre, the Oberon township (as opposed to the wider Oberon local government area) is unusual in that it has significant industry very close to town, as well as being surrounded by significant monoculture plantations of pinus radiata pine trees, and extensive pastures.
While scientific grade air quality stations (for example, as deployed by the NSW government Environmental Protection Authority (EPA) at strategic locations) are quite expensive (upwards of AU$50k), Oberon Citizen Science Network believes a network of cheaper monitoring stations, either commercially available devices and/or DIY versions designed by OCSN members, could provide better coverage and information to the community by being able to account differing air quality in different locations around the town, due to changing weather conditions and wind directions, better than than a single expensive station.
At this stage research is still on going as to the most appropriate air quality monitoring devices to use, but the discussion below covers the various air quality measures and criteria OCSN believes are significant to the Oberon Community.
Air quality indicators
Air Quality Index (AQI)
AQI is an umbrella measure. It’s a good summary measure when air quality is good, but when the AQI is not so good, it gives no clue as to why it is not so good. Sometimes it may be obvious why the AQI is not good but not always.
Particulate Matter (PM)
Particulate Matter (or Particulates) are significant for Oberon due to industry and the associated vehicle activity, and the pollens produced by the surrounding forests and pastures. Being a colder climate Oberon also has a lot of wood-fired heaters being used for a greater portion of the year, which also adds to the exposure to particulates in the air. Unsealed roads can also be a significant source of dust (particulates) affecting those living out of town especially. Bushfires are also of course major contributors to atmospheric particulates.
PurpleAir is one manufacturer of low-cost air quality monitoring devices.
The size of airborne particles, as well as their composition, determines their nuisance and health effects. Dust particles and fibres vary in size from coarse (non-inhalable), to fine (inhalable, sometimes call inspirable), to very fine (respirable).
Coarse dust particles generally only reach as far as the inside of the nose, mouth or throat. Smaller or fine particles, however, can get much deeper into the sensitive regions of the respiratory tract and lungs. These smaller dust particles have a greater potential to cause serious harm to your health. Some types of extremely fine particles (see PM1.0 below) are able to cross the alveolar membranes in the lungs and directly enter the bloodstream, where they can cause general inflammation and increase clotting tendancies which are risk factors for myocardial infarctions (heart attacks) and strokes.
PM10
PM10 particulate matter is particles of 10 micrometres (µm) or less in diameter. It is of significance to Oberon as this size particle includes some types of pollens which can be produced in large quantities from the radiata pine plantations and surrounding pastures (other pollen types are 20 to 50 micrometres in size). Fly ash from the factories (if not adequately collected) and from domestic wood heaters is also in this size range as is a significant portion of sander dust (produced and burned at the factories).
PM2.5
PM2.5 particulates are considered one of the most harmful contaminants due to the ability for these particles to make their way deep into the lungs. Sources of PM2.5 particles include mould spores, house dust, bacteria, fly ash and incompletely combusted solid fuels like sander dust. Incomplete combustion of sander dust in the factories results in a brown plume emanating from the stacks. Bushfires are also significant but intermittent sources of these particulates.
PM1.0
PM1.0 are particularly fine particles which are harnful due to their ability to penetrate the lung membranes and enter the blood stream. PM1.0 particles are currently not regulated to the same extent as PM2.5 but some air quality monitors have the capability to report on PM1.0 separately to PM2.5. Smoke from any source is significant in this particle size range.
Volatile Organic Compounds (VOCs)
VOCs are produced from incomplete combustion, evaporation of fuels and solvents, gas leaks, and also are produced by natural processes, being emitted by plants, animals and micro-organisms.
Nitrogen Oxides (NOx)
NOx is the collective name for nitrogen oxides commonly produced during high temperature combustion. At high temperatures atmospheric oxygen and nitrogen can combine to form these compounds, which can then react with VOCs to produce ozone (O3) or be emitted to contribute to acid rain.
Ozone (O3)
Ozone can be produced by reaction of VOCs with NOx at high temperatures or can be catalysed by UV radiation in sunlight. Ozone is an irritant and causes inflammation and may create free radicals leading to harmful oxidation in the body.
Carbon monoxide (CO) and carbon dioxide (CO2)
Carbon dioxide is a byproduct of burning carbon-containing compounds, such as wood or wood waste. The largest wood processing plant in Oberon operates a co-generation facility in which wood waste is burnt to generate electricity (along with a very large array of solar panels on the factory’s roofs). CO2 which results from this combustion is emitted via stacks some distance above the round, allowing the CO2, which is heavier than air, to disperse. However, in some conditions, particularly in still air, the emitted CO2 may sink to ground level before it has dispersed, and thus the concentration may rise in the vicinity of the source. It is very unlikely to reach dangerous levels, but changes in CO2 levels in outdoor air may be interesting to monitor.
Carbon monoxide (CO) is produced by partial combustion of carbon-containing materials in the presence of insufficient oxygen. Usually only low levels should be emitted, but CO is very toxic, and thus monitoring for even small rises is not unreasonable.
Indoor air quality
Indoor air quality is also very important, and there are several sources of air pollutants which may be present in indoor environments. These include unflued gas heaters and gas stoves, which may emit CO2, CO and nitrogen oxides, wood heaters which may emit CO2, CO and particulates, and furniture and fittings made of particle board or other manufactured woods, which may emit low levels of volatile organic compounds (VOCs) used in the manufacture. And of course, humans (and other animals) emit gases, particularly CO2, which can build up in poorly ventilated buildings with many people inside (eg classrooms).
Monitoring indoor air quality is also on the OCSN agenda, to complement monitoring of outdoor air quality.