Pulp (non)fiction: air pollution in the pulp and paper industry

Professor Wayne Gray's research

That piece of paper you're about to throw away not only cost a tree its life, but its manufacture may have polluted the air you breathe. The paper and pulp industry has been notorious in the past for its contribution to air and water pollution. However, thanks in part to more stringent environmental regulations, this pollution has been reduced in recent decades.

For the past few years economist Wayne Gray, assisted by his former graduate student Dr. Ronald Shadbegian (now a professor at the University of Massachusetts at Dartmouth) and undergraduate Melanie Lajoie '01, has been studying the environmental regulation of the pulp and paper industry. Go to an online interview about Melanie's research or continue reading to find out about Gray and Shadbegian's study of factors related to the decline in air pollution in this industry.

Air pollution in the pulp and paper industry
Data sources
Expectations
Conclusions

Air pollution in the paper industry

As part of the manufacturing process, pulp and paper mills generate sulfur dioxide and particulate matter-dust, soot, and ashes--from the burning of fossil fuels like coal and oil for energy. Both pollutants can cause respiratory problems, damage to property, and reduced atmospheric visibility. Sulfur dioxide contributes to acid rain that can devastate forests hundreds of miles from its source.

Fortunately, with the passage of the 1970 Clean Air Act and the 1972 Clean Water Act (and subsequent amendments) federal regulations were put in place to begin the process of water and air cleanup, and to curb the output of pollutants in the future. Newly built paper and pulp mills had to meet strict regulations designed to reduce or eliminate pollution. Regulations for mills already in existence were less strict, in part because of the expense of retrofitting anti-pollution devices. Pollution control strategies could consist of

End-of-pipe remedies (devices connected to smokestacks and designed to remove particulates and sulfur dioxide)
Change-in-process remedies (modifying the manufacturing process in such a way that less pollution is generated)

Data and data sources

Gray and Shadbegian utilized the following information for their study of 68 U.S. pulp and paper mills during the period 1979-1990.

The amount of air pollution (sulfur dioxide and particulates) generated by each mill (from Environmental Protection Agency (EPA) databases)
The methods (end-of-pipe vs. change-in-process) used by each mill to reduce air pollution and the money spent on pollution control (from the Pollution Abatement Costs and Expenditures (PACE) survey conducted by the U.S, Census)
Each mill's annual production level, investment, productivity, age and type of manufacturing technology (from the U.S. Census's Longitudinal Research Database (LRD) and Lockwood's Directory of the Paper and Allied Trades)
Local environmental regulations
- Air quality attainment status-whether or not each county containing a mill met air quality standards (from the Federal Register) - mills in dirtier counties face stricter regulations
- Attitude (strict or lax) toward environmental regulation for the state in which the mill is located (from the League of Conservation Voters' pro-environment voting score for each state's congressional delegation during each congressional session)

Expectations

Gray and Shadbegian hypothesized that higher emissions would be associated with

More capital-intensive production (more machinery and bigger factories)
Pulping as opposed to paper mills (mills producing their own pulp from wood tend to generate more pollutants than mills that manufacture paper from pulp purchased elsewhere).
Older mills (newer mills should generate less pollution because they must comply with stricter anti-pollution regulations).

Gray and Shadbegian also hypothesized that lower levels of emissions would be associated with

Mills that had larger investments in pollution control
Higher operating costs
Stricter local anti-pollution regulation
Greater state-level political support for environmental regulation

Conclusions

The researchers used statistical techniques to examine the data. They concluded that

Total emissions (sulfur dioxide and particulates) were significantly lower in mills with larger amounts of money invested in pollution control.
Investment in end-of-line anti-pollution methods seemed to be more clearly connected with lower emissions than were change-in-process methods
Mills in counties that had not met air quality standards had lower emissions than those in counties that had met standards (an outcome of the stricter regulation they faced)
Higher productivity was associated with lower emissions
Higher emissions were (surprisingly) associated with higher operating expenditures for pollution abatement
Pollution abatement investment had more of an impact on sulfur dioxide emissions than on particulate emissions
Political support for stricter regulation was associated with lower emissions.