Airborne dust absorption by semi-arid forests reduces PM pollution in nearby urban environments

Uni, D. and Katra, I., 2017. Science of the Total Environment

Original research (primary data)
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Dust storms are a major source of global atmospheric particulate matter (PM), having significant impacts on air pollution and human health. During dust storms, daily averages of atmospheric PM concentrations can reach high levels above the World Health Organization (WHO) guideline for air quality. The objective of this study was to explore the impact of forests on PM distribution following dust events in a region that is subjected to frequent dust storms (Northern Negev, Israel). Dust was measured in a forest transect including urban environments that are nearby the forest and at a distal location. During a background period, without dust events, the forest with its surrounding areas were characterized by lower monthly average of PM concentrations (38 ?g/m3) compared with areas that are not affected by the forest (54 ?g/m3). Such difference can be meaningful for long-term human health exposure. A reduction in PM levels in the forest transect was evident at most measured dust events, depending on the storm intensity and the locations of the protected areas. A significant reduction in PM2.5/PM10 during dust events, indicates the high efficiency of the forest trees to absorb airborne PM2.5. Analysis of dust particles absorbed on the foliage revealed a total dust deposits of 8.1–9.2 g/m2, which is equal to a minimum of 418.2 tons removed from the atmosphere per a forest foliage area (30 km2). The findings can support environmental strategies to enhance life quality in regions that are subjected to dust storms, or under potential risk of dust-related PM due to land use and/or climate changes.

Case studies

Basic information

  • Case ID: INT-182-1
  • Intervention type: Created habitats
  • Intervention description:

    Afforestation activities … Lahav forest covers an area of N 30,000 ha …The predominant tree species that was planted 60 years ago in the Negev forests is the Aleppo pine (Pinus halepensis) due to its relatively high resistance to drought and salinity stress

  • Landscape/sea scape ecosystem management: Yes
  • Climate change impacts Effect of Nbs on CCI Effect measures
    Other climate impact  Positive Atmospheric particular matter (PM) concentration ratio (OF ratio), in which the concentration at each measurement point was divided by the concentration measured at the West point [where the dust storm originates]. fine fraction content can be defined by the ratio PM2.5/PM10 outcome measures reported during non-storm days (background rate) as well as during/after storms
  • Approach implemented in the field: Yes
  • Specific location:

    The study was conducted in the northern Negev region, Israel … in the The Lahav forest site

  • Country: Israel
  • Habitat/Biome type: Created forest |
  • Issue specific term: Not applicable


  • Notes on intervention effectivness: Effectiveness determined by comparing the outcome measures in a built environment near the forest and in another built environment that was outside the influence of the forest. Also looked at the measures where the storm originated versus within and the opposite side of the forest. “In background periods without dust storm events, the forest with its surrounding areas are characterized by lower PM concentrations com- pared to areas that are at distal locations and thus are not protected by the forest.” “The results show that in medium and high level storms, PM10 con- centrations in an urban environment that is located at the leeward side of the forest (Lahav) can be reduced by 28% compared with those of a nearby urban environment that is not affected by forest (Lakiya).” “These changes in PM2.5/PM10 indicate that dur- ing dust storms the filtering process by the trees affects both fine and course fractions, however the efficiency to reduce the fine fraction is somewhat higher than that of the coarse fraction”
  • Is the assessment original?: Yes
  • Broadtype of intervention considered: Not applicable
  • Compare effectivness?: No
  • Compared to the non-NBS approach: Not applicable
  • Report greenhouse gas mitigation?: No
  • Impacts on GHG: Not applicable
  • Assess outcomes of the intervention on natural ecosystems: No
  • Impacts for the ecosystem: Not reported
  • Ecosystem measures: N/A
  • Assess outcomes of the intervention on people: No
  • Impacts for people: Not reported
  • People measures: N/A
  • Considers economic costs: No
  • Economic appraisal conducted: No
  • Economic appraisal described:
  • Economic costs of alternative considered: No
  • Compared to an alternative: Not reported

Evaluation methodology

  • Type of data: Quantitative
  • Is it experimental: Yes
  • Experimental evalution done: In-situ/field
  • Non-experimental evalution done: Not applicable
  • Study is systematic: