What impact does the production and use of HMA have on the environment?

In many respects Hot Mix Asphalt (HMA) is the environmentally friendly paving material. First, HMA materials are 100% recyclable. Virtually all of the reclaimed Asphalt Pavement (RAP) that is removed from existing streets and highways is recycled into new HMA. Because this recycling of HMA is economical, it occurs without the need for government mandates or subsidies.

The use of Asphalt pavement can result in environmentally friendly, sustainable development as well. For more information on this subject visit the Asphalt Education Partnership website www.beyondroads.com and http://www.asphaltroads.org/Environment

HMA also has been shown to consume less energy than other materials and systems. A study done by the Asphalt Institute indicated that a comparably designed HMA pavement required only about half the total energy to construct as a comparable portland cement concrete pavement.

Improvements in technology have been steadily reducing the airborne emissions from the production and placement of HMA. Dust from the drying of aggregates is the major emission and is now almost totally captured and recycled. Other emissions are primarily combustion products from the burning of fuel to heat the aggregates and fumes from hot asphalt itself. Fuel burners are now much more efficient, resulting in very complete combustion. Studies to date by the government and industry have shown emissions levels to be very low and have not identified any health hazard associated with exposure to asphalt fumes. Nevertheless , the industry continues to develop improved technology for reducing emissions and minimizing exposure.

To read articles relating to the environmental effects of HMA production, see below.

HMA Plants Removed from Sources Subject to MACT Standards
Clearing the Air - HMAT 2001
Tests Show Low Emissions

For more information on this subject, see the following publications of the Asphalt Institute:
PR-1, Environmental Applications for Hot Mix Asphalt;
RR-75-1A, Asphalt Hot Mix Emission Study;
RR-80-1, Exposure of Paving Workers to Asphalt Emissions;
IS-173, Energy Requirements for Roadway Pavements

and of the National Asphalt Paving Association
SR-166, Evaluation of Stack Emissions from HMA Facility Operations;
IS-123, PS-23, Special Report #134, Study of Paving Asphalt Fumes; and, 
press release ; "Asphalt Pavement is the surprise leader in recycling---"