Artificial Turf, is it "green"?

Earlier this year I undertook a small research project to determine a position on artificial turf that was being advocated for a local private school. The answers I found were not a clear cut opinion forming as I thought they might be...

The Artificial Turf Sustainability Issues
WATER: No water is required for irrigation, but the field still requires water for cooling surface on extremely hot days.

HEAT ISLAND EFFECT/AIR QUALITY: With surface temperatures can be 20-40 degrees higher than natural grass playing fields, not only is the HIE very high but the effects on the participants is dangerous, raising the risk of heat related injuries (i.e. heat stroke)

STORMWATER/GROUNDWATER POLLUTION: As a constructed system with a sand and gravel base, an artificial turf field provides a high rainwater infiltration while filtering out sediments and providing storage capacity. Artificial turf reduces some pollution in run-off water by trapping larger particles, but still requires cleaning (vacuuming) to retain its permeability. The "mulch" bedding made from recycled tires is again something that sounds very green on the surface but studies are finding issues with toxins in that mulch getting into places we don't want.

NATURAL PROCESS: Seems an obvious CON on a Pro/Con list, but the reason specifically is not obvious. Unlike when you mow a natural turf field there is no opportunity for minor organic matter breakdown (small scale composting) that is the blades of grass breaking down.

EMBODIED ENERGY/CARBON FOOTPRINT: Artificial turf fibers and backing are petroleum-based, so manufacturing is not sustainable in this case. Also the longevity of the field in peak condition is 5-years. Beyond that the condition of the field begins to degrade. Lifetime varies with use-intensity. Industry standard warranty period is 8 years, after which thefield may need replacement. Lifecycle costing needs to be calculated.

GENERAL SAFETY: Artificial turf today does not match natural grass safety statistics despite remarkable decreases in ligament damage from lateral “plant and release” motions in playing conditions from earlier versions of artificial turf. Another couple of recent findings found lack of a natural bacteria processing that natural grasses can provide have been linked to increased exposure to bacterial infections (i.e. staph infections).Articles appear to lean towards the causes for increased staph presence not necessarily linked to the surface itself but rather the surface providing more abrasions than natural grass, thus having more entry points for staph to invade the blood stream. Also evidence of lead have been found in the "mulch" material causing some health concerns.

The Natural Turf Sustainability Issues:
WATER: High water use for irrigation.

HEAT ISLAND EFFECT/AIR QUALITY: Combats Heat Island effect, it is a source of cooling.

NATURAL PROCESS: Natural turf is a great processor of CO2 (photosynthesis). Grass clippings and leaf collection can be used for composting throughout the campus though.

STORMWATER/GROUNDWATER POLLUTION: Reduces pollution in some regards by trapping dust and dirt as well as particulates and bacteria as well as absorbing noise. But its high use of toxic and questionable ingredients in the field fertilizers, herbicides, insecticides, fungicides and field paints, but many sustainable strategies are emerging to reduce toxics. Controlling run-off and stormwater infiltration depends on what is underneath the surface (e.g. drainage system, soil profile).

EMBODIED ENERGY/CARBON FOOTPRINT: High Energy-intensive maintenance with the need for mowing, re-
seeding, and painting of field. The longevity of the field over time depends on the level of use. Practice fields are necessary to maintain condition of “game day” fields.

GENERAL SAFETY: Natural turf fields are still better for prevention of turf related injuries.

Summary
While it is difficult to endorse an artificial surface in lieu of natural grass in the greater context of nature and sustainability, the determination of a school’s needs may very well suggest the use of the artificial surface may be appropriate. Where issues such as lack of parking near the athletic fields, an artificial turf field might eliminate the need for one practice field, which could be converted to permanent parking. However, lifecycle cost and floodplain-related issues need to be assessed in every case.

- Stephen