by Galveston-Houston
Association for Smog Prevention

In May 1996, the Natural Resources Defense Council (NRDC) released an extensive study that calculated the annual number of deaths due to particulate air pollution in 239 U.S. metropolitan areas -- including Houston. The result? In the Houston area, an average of 939 (range 558-1,287) people die each year from breathing the current levels of particulates in our air. This is three times the number of homicides -- 316 -- that occurred in Houston in 1995. And for every death, thousands more flock to area emergency rooms and to their physicians for medical care, and thousands more miss school or work.

What is particulate pollution?

Ever noticed a white haze obscuring Houston's skyline? That is particulate pollution. Particulate pollution consists of tiny solid particles, as well as tiny liquid droplets known as aerosols. The smallest particles, those 2.5 microns or less in diameter (PM2.5) which are formed largely by combustion, are the most dangerous because these are carried deep into the lungs.

Our sky is in effect a sprawling dump ground -- and each of us is dumping. Houston-area industries release millions of pounds of particulates into our air each year. The top contributors? Mobil Mining & Minerals, Simpson Pasadena Paper Company, Houston Lighting & Power, and Exxon Company USA Refinery. These four companies alone report releasing some 6.3 million pounds of particulates each year.

In addition, over one million cars, diesel buses and trucks on our streets and highways emit a continual trail of toxic particulates in their exhaust, and every tire is releasing its own trail of dangerous particles (ever think of where your tires' tread goes?). And street and highway construction generates another toxic plume.

Other sources include cigarette smoke, incinerators, gasoline-powered lawnmowers and leaf-blowers, and wood and charcoal fires. In addition some particulates, such as sulfates, nitrates and various organic aerosol compounds, are manufactured in the atmosphere from gaseous pollutants.

How do particulates affect one's health?

All particulates trigger powerful inflammatory reactions in the lungs which exacerbate asthma, decrease lung capacity and create ideal conditions for infections. In addition, some particulates form powerful acids which damage the lining of the respiratory system; others carry toxic chemicals directly into the blood stream; and still others, such as latex from radial tires, cause powerful allergic reactions. Particulate pollution also stimulates the release of agents into blood vessels which damage the lining of blood vessels. Strokes, heart attacks, pneumonia, flu, asthma and bronchitis are the most common causes of particulate-induced deaths. Particulates have also been linked with cancer, especially lung cancer.

How bad are the particulate levels in Houston?

The current federal standard is based on particulate matter 10 microns in diameter and smaller (PM10), of which generally about 60% is the smaller particulates, PM2.5. Although Houston does not currently exceed the federal standard for PM10 (an annual average of 50 micrograms/m3), scientific evidence has convincingly shown that the current standard fails to protect health. Accordingly, the EPA is in the process of revising the particulate standard, and is expected to propose a significantly lower standard, one which will focus on the smaller PM2.5 faction, in November 1996. Preliminary documents suggest that an annual PM2.5 standard between 12.5 and 20 micrograms/m3 will be chosen. The NRDC and the American Lung Association (ALA) recommend an annual PM2.5 standard of 10 micrograms/m3.

In Houston, the average PM10 level (no PM2.5 data for Houston exists) between 1990 and 1994 was 31.9 micrograms/m3; however the average level along the ship channel was considerably higher: 42.8 micrograms/m3. If PM2.5 levels in the Houston area are 60% of the PM10 levels, then the area's average annual PM2.5 levels are between 19.1 and 25.8 micrograms/m3 -- generally above the EPA's recommended standard, and twice the standard proposed by the NRDC and the ALA.

The particulate levels in the Houston area are particularly troubling not only because of the high levels of ozone smog and toxic chemicals in our air -- both of which exacerbate the adverse effects of particulates, but because area leaders have steadfastly refused to make the hard decisions necessary to reduce area pollution. Consequently, particulate levels in Houston have increased over the last decade (Harris County now leads the state in PM10 levels), and ozone exceedances increased precipitously last year (in 1995 the highest ozone smog level in the nation was recorded in Harris County). Unless we make major changes, the area's future is dim.

What can one do?

• Drive less. Vanpool, carpool, ride the bus, walk, bicycle. Encourage significant parking fees, bus and vanpool subsidies, incentives to leave one's car at home.

• Use only manual or electric lawn care equipment.

• Replace wood-burning fireplaces and charcoal grills with natural gas models.

• Maintain your car properly. Vigorously support emissions' testing.

• Get involved. Report polluters (713-640-4200), support strict regulation of industrial emissions, organize a neighborhood pollution task force, elect officials committed to cleaner air.