B7 Reducing the health impacts of dust
Many communities experience problems with dust, either caused by unsealed roads and surfaces in the community or blown into the community from surrounding arid, rural or drought affected lands.
Dust causes direct health problems by irritating the skin and parts of the body that secrete mucus, which contributes to eye diseases such as trachoma, respiratory disease and skin infections. This section deals with design strategies for the house and living area that will reduce the direct impact of dust on people’s health. Most wind driven dust occurs within a metre of the ground and causes the majority of problems.
Where roads or the edges of a road are not sealed, motor cars may generate high levels of dust. If the house yard is not fenced, it will be hard to control the movement of vehicles around the house and to establish landscaping, which can reduce dust from surrounding areas entering the house.
Evaporative cooling systems, which are most efficient in hot, dry climates, push large volumes of cool air into the house and the pressure generated in the house reduces the entry of dust.
Dust can also affect the performance of health hardware. For example, solar hot water collection panels will be less effective when covered in dust; appliances such as washing machines have a shorter life due to the build up of dust in moving parts; and the function of sliding doors and windows can be affected by dust build up. In dust prone areas, particular attention needs to be given to the selection of health hardware to ensure it will not fail.
Dust can transmit animal and bird droppings and bacteria to roofs and may contaminate the water supply.It may be necessary to disinfect the community’s water supply, after other treatments, to protect against contamination by dust borne particles.
Survey data shows that 44 per cent of houses had at least one working motor car in the yard at the time of survey. Less than a third (30 per cent) of surveyed houses had a fenced yard and only 22 per cent had windbreak planting to reduce the movement of dust in the yard. However, 96% of surveyed houses had at least one working yard tap available to assist in establishing dust control planting.
Over half of surveyed houses (58 per cent) were located in a climate in which the maximum summer temperature regularly exceeded 40°Celsius, indicating hot, dry and dusty conditions. However, ducted evaporative cooling systems were present in only ten per cent of all houses and a third of houses (33 per cent) had no cooling system installed.
Design and specification
Ensure:
- wall to floor junctions are detailed to exclude dust from the house
- weather strips are specified for all external doors
- windows can be sealed against dust coming into the house
- insect screens are fitted to windows and doors to assist in filtering dust and the screens can easily be removed for cleaning
- in areas prone to dust storms, all openings and vents in the house can be secured against dust entering the house
- concrete, paving or gravel is used near house entrances to reduce dust
- at least one of the verandahs or outside living areas is facing away from prevailing, dust-carrying wind
- yard areas are covered with lawn, ground cover, gravel or mulch, and the yard is shaped to capture and direct rainwater that can be absorbed by plants in the yard
- yard taps are provided and located to allow a hose or drip irrigation line to reach all areas of the yard.
Drip irrigation lines are known to consume large volumes of water because they can be turned on and forgotten; to avoid wasting water fit a timer device between the tap and the irrigation line and check local water restrictions.
Consider:
- raising floor levels to above 1 metre, or a combination of floor and window sill levels to 1 metre above the ground
- not using timber decking in extremely dusty areas as the dust could blow up from below the deck
- having all window sills at approximately 1 metre above the ground but consider whether this will reduce effective cross ventilation in the tropics, and talk with community members about whether this would change what they can see from the house
- providing low walls, screens or landscaped mounds to verandahs and outside living areas
- using fences, rocks or other barriers, to keep vehicles out of landscaped and unsealed areas
- sealing driveways, parking areas and paths
- building landscaped earth mounds, growing vines on low fences, or planting dense shrubs on the yard perimeter and on the edges of any outside living areas that are exposed to dust carrying winds
- installing rainwater tanks to collect water for watering plants and, if the water is also used for drinking, using a first flush device to divert the first load of polluted water from the roof away from the tank (see B4.1 Quality of Drinking Water)
- providing an irrigation system, particularly along the fence line or landscaped mounds, to water trees, fruit and vegetable plants, and create wind breaks with vines inside and outside the yard.
Quality control
During construction and before making the final payment, check that:
- wall to floor junctions are sealed
- weather strips are fitted on external doors
- areas around doorways and windows are sealed as specified
- yard taps and irrigation systems are installed, secured and working
- the yard has been landscaped and planted as specified in the contract, and the plants are alive and established
- fencing, if specified, is installed and secure and all gates work
- rainwater tanks, if specified, are secure and downpipes are connected to the tanks and if the water is to be used for drinking, a first flush device has been fitted
- the yard has been shaped and graded to direct water to garden areas.
Maintenance
As part of cyclical maintenance, check and, where necessary, repair or replace:
- weather strips on doors and seals on windows
- fences and gates
- the condition of lawns and plants
- the function of taps and irrigation systems
- gutters, downpipes and rainwater tanks
- clean insect screens to remove dust.
| Reducing dust in the community | Percentage of houses | Total houses surveyed | Change since 2003* |
|---|---|---|---|
| Yard fences encourage the development of dust reducing landscaping | |||
| No fenced yard | 30% | 3,661 | |
| Fenced yard area at least 900 square metres | 37% | 3,661 | |
| Fenced yard area less than 900 square metres | 33% | 3,661 | |
| Wind break planting in the yard | 22% | 3,662 | |
| No yard taps | 4% | 3,660 | |
| 1 yard tap | 26% | 3,660 | |
| 2 yard taps | 59% | 3,660 | |
| 3 or more yard taps | 11% | 3,660 | |
| Cars can generate dust | |||
| No working motor cars in yard | 56% | 3,660 | |
| One working motor car in yard | 28% | 3,660 | |
| Two working motor cars in yard | 10% | 3,660 | |
| Three or more working motor cars in yard | 6% | 3,660 | |
| Cooling systems—that may reduce dust entering the house | |||
| Maximum summer temperature regularly greater than 40°C | 58% | 3,662 | << |
| Reverse cycle, refrigerated, air ducted cooling system | 4% | 3,662 | |
| Reverse cycle, refrigerated, air non-ducted cooling system | 10% | 3,662 | |
| Evaporative ducted cooling system | 10% | 3,662 | |
| Evaporative non-ducted cooling system | 3% | 3,662 | |
| Ceiling fans | 40% | 3,662 | |
| No cooling system | 33% | 3,662 |
* See ‘Changes in the conditions of houses’ for an explanation of the symbols used in this column.
Standards and references
Lansingh, Dr Van C 2005, Primary health care approach to trachoma control in Aboriginal communities in Central Australia. PhD thesis, Ophthalmology, Centre for Eye Research Australia, University of Melbourne
Seidel, M. 2002, Dust control, Bush Tech #14, Centre for Appropriate Technology, Alice Springs
Godjin, Z 2001, Harvesting of Stormwater in Remote Arid Indigenous Communities using examples from Kalka and Piplayatjara in the Anangu Pitjantjatjara Lands South Australia, Rio Tinto/Centre for Appropriate Technology Inc.
Pholeros, P 1991, AP Design Guide, Building for Health on the Anangu Pitjantjatjara Lands, Nganampa Health Council Inc., Alice Springs, pp. 46-7.