Managing Air Pollution from Natural Sources

Air pollution from natural sources includes mostly dust. Dust is a general name for minute solid particles of diameters less than 500 micrometers and, more generally, for finely divided matter. Soil dust lifted up by wind from vegetation free land. It can also result from volcanic eruptions, or as discharge from industries. Airborne dust is considered an aerosol and can have a strong, local radiative forcing on the atmosphere and significant effects on climate.

Air pollution from dust is difficult to control and to manage. However, there are some general strategies in reducing the dust exposure within an urban setting.

Strategies	Expected improvement of air quality and other advantages	Disadvantages	Comments and city examples
Paving of unpaved roads	Lessen dust in the air	Expensive, needs to be balanced against alternative infrastructure improvements, such as sanitation.	Implemented in many urban areas.
Establishment of speed control devices on unpaved roads	Reduces effectively the dust raised by speeding vehicles; also increases the traffic safety	Requires enforcement and/or physical devices	Implemented in many urban areas.
Establishment of dust control areas with planted vegetation	Planted vegetation helps reduce the generation and dispersion of dust	no known disadvantage	Johannesburg, South Africa: Dust had presented a major problem near sand and sludge dumps composed of mine tailings. However, the establishment of dust control areas has resulted in the extensive plantations of many of these dumps. The dust dispersion could be reduced.
Use of motor oil for dust suppression	Lessen dust in air	Health and environment concerns. During use in engines, oil becomes contaminated with combustion byproducts and metals from engine wear and tear. These contaminants can include carcinogenic (cancer causing) polycyclic aromatic hydrocarbons (PAHs) and metals such as aluminium, cadmium, chromium, lead and copper. On the roads, these contaminants bind to dust particles, and can then be washed off roads by rainfall or blown into the air. Some of the used oil may also simply evaporate into the air. Humans may ingest these harmful materials through drinking contaminated water or breathing in contaminated air or dust.	This practice is banned in many developed countries. Alternatives (such as paving, chemical dust suppresants and water) exist.
Regular street sweeping (manual or with sweeping equipment)	Reduces the amount of lose dust in the paved streets	no known disadvantage	Pusan, Korea: Increasing use of street sweeping equipment, including vacuum sweeping systems (only for paved streets of course). This was part of a whole package of response options to address the SPM problem. The main contributors to the SPM concentrations are industries burning fossil fuels.