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Reducing Smog through Sustainable Groundskeeping

Atlanta's air quality problems are the topic of much debate and discussion in the metro area. Our high ozone levels create acute and chronic respiratory health risks, and our current status as a Severe Ozone Non-Attainment Area (as determined by the U.S. EPA, relating to our compliance with the Clean Air Act of 1990) deters new businesses (and their associated jobs and tax revenues) from moving to our region.

Many ozone reduction initiatives in place relate to reducing automobile Volatile Organic Compound (VOC) and Nitrous Oxides (NOx) emissions, which create ground-level ozone when they react with sunlight. However, one large source of VOCs and NOx that is often overlooked is groundskeeping or landscaping activities. Reducing the use of inefficient gas-powered lawn maintenance equipment is currently a focus of the Georgia Environmental Protection Division’s voluntary Partners for a Smog-Free Georgia (PSG) program. This program encourages the development of plans to reduce ozone-generating emissions at the source, and recognizes that significant opportunities for improving local air quality also exist in groundskeeping or landscaping activities.

As small gas-powered engines begin to age and performance deteriorates, VOCs and NOx emission rates increase. The actual quantity of air pollutants released and the rate at which the emissions increase over time is dependent upon the year in which the engine was manufactured and the type of engine design chosen. The U.S. EPA Office of Mobile Sources developed the Phase I Small Spark Ignition Engine Rule, affecting the market for groundskeeping equipment since 1996. It was estimated that overall VOC and NOx emissions from Post-1996 spark-ignited engines have decreased by 32%. The new Phase II ruling, which takes effect in 2002, will require manufacturers to design small gas-powered engines to meet an additional 78% reduction in both VOC and NOx emissions.

Overhead valve engines produce lower VOC and carbon monoxide (CO) emissions because the combustion process is faster and fuels burn more uniformly. Overhead valve engines are constructed of high-strength materials to withstand an increased friction and heat load and therefore, the overall lawnmower cost is slightly higher. Side-valve engines characteristically experience incomplete combustion (High CO emissions) and higher levels of VOC emissions. However, it should be noted that the differences in emission rates between overhead and side-valve engines designed after 1996 become less significant. The table below illustrates estimated hourly emissions for new and used 4-stroke, overhead valve lawnmowing equipment in comparison to an average emission rate for automobiles.

Comparison of Emission Rates from Lawnmowing Equipment and Automobiles

It is very clear that as pre-1997, gas-powered engines used in lawnmowing equipment approach median life, they become significant mobile-source contributors to ozone formation. When compared to average hourly automobile emission rates, aged pre-1997 lawnmowers show a greater potential to impair air quality in Metro Atlanta in an equivalent time frame. Even new small-engine models, while showing a slightly lower emission rate than the average automobile on the road, play a significant role in smog development, primarily due to the quantity being used by consumers.

Discontinuing the use of gas-powered lawnmowers and trimmers altogether, in favor of electric-powered or manual equipment is the ideal solution. If complete conversion is not feasible, an organization should evaluate the current groundskeeping equipment fleet and specific practices being used to determine where air quality impacts can be reduced.

Opportunities to reduce ozone-forming emissions during groundskeeping activities are provided in the box below.

How to Reduce your Contribution to Ozone Formation

Reduce Lawnmowing Time in One-Hour Increments ÷ Map out the most time efficient mowing route ÷ Minimize turf areas that require mowing by planting low-maintenance and low water demanding groundcovers ÷ Plant turf grasses and grass/flower combinations which exhibit slower grass growth rates ÷ Reduce turf grass mowing acreage by constructing artificial turf putting greens ÷ Plant low-maintenance native flower gardens ÷ Preserve natural areas or reseed natural plant life that requires minimal maintenance ÷ Use Bermuda grass seed and PRIMO growth regulator to reduce grass growth rates (Most applicable to golf courses) These practices can also be used as Sustainable Incentive-Based Services provided by the groundskeeping company Require/Recommend Groundskeepers to Follow Sustainable Guidelines via Written Contracts < First Step: Review Specifications of Lawn and Garden Groundskeeping Equipment Currently Used > ÷ Use alternative equipment when feasible (i.e. electric-powered or manual) ÷ Discontinue use and encourage recycling of pre-1997 models (Use new, high-efficiency equipment) ÷ Switch to gas-powered equipment built with 4-stroke engines (and overhead valve designs where feasible) ÷ Use wide mowing deck equipment to reduce total lawnmowing time ÷ Winter-proof to slow deterioration/aging (Drain oil and fuel, clean the engine, and inspect all major components) ÷ Keep mower blades sharp and underside of mower clean ÷ Change oil, clean/replace air filters, conduct tune ups, and adjust carburetor as specified by the engine manufacturer ÷ Use "non-spill" gasoline containers Homeowners can utilize most of these recommendations as well. Additionally, homeowners should consider planning all gas- powered landscaping activities after 6 PM to reduce ozone-forming potential.

Improving the quality of living for all Metro Atlanta residents through reducing ozone-forming emission sources is the ultimate goal of the PSG Program. All of the measures described within this report can help prevent significant deterioration of local air quality. By implementing these pollution prevention recommendations an organization will be actively assisting the state of Georgia in improving overall sustainability. The PSG Program welcomes participation from any organization.